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fix: B7 — CCR hardening: persistent backends + always-on tool

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P2-25, P2-26: CCR (Compress-Cache-Retrieve) used an in-memory store
that fragmented across uvicorn workers and was wiped on restart, and
the `headroom_retrieve` tool was registered/unregistered per-request
based on whether the latest body happened to contain compression
markers — every flip busted the prompt cache. Both are sticky
side-channels: once a session has done CCR, the tool list bytes and
the retrieval store must stay stable. This PR fixes both.

Rust:
* Split `ccr.rs` into `ccr/` with `backends/` submodule
  (`in_memory.rs`, `sqlite.rs`, `redis.rs` cfg-gated).
* `SqliteCcrStore` (production default): WAL mode, prepared upsert,
  lazy TTL purge on read, persistent across worker restarts and
  shareable across workers on the same host via SQLite file locking.
* `RedisCcrStore` (cfg-gated behind `feature = "redis"`): SETEX with
  startup PING smoke-test, no key-prefix collision risk, no sticky
  session required at the LB.
* `CcrBackendConfig::{InMemory, Sqlite, Redis}` + `from_config(...)`
  factory — every init failure surfaces (no silent fallback per
  `feedback_no_silent_fallbacks.md`).
* `ccr::compute_key` (BLAKE3 → first 24 hex chars) and
  `ccr::marker_for("HASH") -> "<<ccr:HASH>>"` centralize the hash +
  marker format; one definition for the live-zone dispatcher and the
  Python regex (`headroom/ccr/tool_injection.py:211`).
* `compress_anthropic_live_zone_with_ccr` accepts
  `Option<&dyn CcrStore>`. When wired, every accepted compression
  puts the original bytes into the backend and appends `<<ccr:HASH>>`
  to the compressed string. The token-validation gate runs on the
  marker-augmented string so the `compressed_tokens >=
  original_tokens` rejection stays honest.

Python:
* `SessionCcrTracker` + `apply_session_sticky_ccr_tool` mirror the
  PR-A7 `SessionToolTracker` / `apply_session_sticky_memory_tools`
  pattern: once a session has done CCR, every subsequent request
  injects the recorded golden tool-definition bytes. Tool list bytes
  are byte-stable across turns (snapshot test pins them).
* `headroom/ccr/tool_injection.py::inject_tool_definition` accepts a
  new `session_has_done_ccr` kwarg per the PR-B7 spec change at line
  302-328. The legacy per-request path stays intact for callers that
  don't yet thread a session id (e.g. Google handler).
* Anthropic + OpenAI handlers route their CCR tool-list updates
  through `apply_session_sticky_ccr_tool`, keyed off the existing
  `session_tracker_store.compute_session_id(...)` plumbing.

Backend selection model: `CcrBackendConfig::Sqlite { path }` is the
production default — single host, persistent, multi-worker safe with
sticky session. `CcrBackendConfig::Redis { url }` is the multi-host
scale-out option — no stickiness needed. `InMemory` is for tests
and single-worker dev only. RUST_DEV.md "Multi-worker deployment —
CCR fragmentation" rewritten around this matrix.

Tests:
* `crates/headroom-core/tests/ccr_backends.rs` — 7 tests covering
  SQLite round-trip, TTL purge, proxy-restart survival, cross-backend
  byte-equal keys, `from_config` paths, and the no-redis-feature
  loud-failure check (+ 2 redis tests gated behind the feature).
* `crates/headroom-core/tests/live_zone_ccr.rs` — confirms
  `<<ccr:HASH>>` marker injection, store population, and
  no-marker-when-no-store invariants end-to-end.
* `tests/test_ccr_tool_always_on.py` — 12 tests pinning the
  always-on behaviour, session/provider isolation, LRU bound, no-
  session-id fallback, and (per-acceptance-criterion) the byte-stable
  tool-definition snapshot.

Per-PR-B7 plan: REALIGNMENT/04-phase-B-live-zone.md.
This commit is contained in:
chopratejas 2026-05-02 16:49:08 -07:00
parent 2ee05774b9
commit 00902b8fea
16 changed files with 2021 additions and 137 deletions
Download patch file Download diff file Expand all files Collapse all files

136
Cargo.lock generated
View file

@ -123,6 +123,15 @@ version = "1.4.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "c3d036a3c4ab069c7b410a2ce876bd74808d2d0888a82667669f8e783a898bf1"
[[package]]
name = "arc-swap"
version = "1.9.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "6a3a1fd6f75306b68087b831f025c712524bcb19aad54e557b1129cfa0a2b207"
dependencies = [
"rustversion",
]
[[package]]
name = "arg_enum_proc_macro"
version = "0.3.4"
@ -134,6 +143,12 @@ dependencies = [
"syn",
]
[[package]]
name = "arrayref"
version = "0.3.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "76a2e8124351fda1ef8aaaa3bbd7ebbcb486bbcd4225aca0aa0d84bb2db8fecb"
[[package]]
name = "arrayvec"
version = "0.7.6"
@ -349,6 +364,20 @@ dependencies = [
"no_std_io2",
]
[[package]]
name = "blake3"
version = "1.8.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "0aa83c34e62843d924f905e0f5c866eb1dd6545fc4d719e803d9ba6030371fce"
dependencies = [
"arrayref",
"arrayvec",
"cc",
"cfg-if",
"constant_time_eq",
"cpufeatures 0.3.0",
]
[[package]]
name = "block-buffer"
version = "0.10.4"
@ -529,6 +558,16 @@ version = "1.0.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
[[package]]
name = "combine"
version = "4.6.7"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "ba5a308b75df32fe02788e748662718f03fde005016435c444eea572398219fd"
dependencies = [
"bytes",
"memchr",
]
[[package]]
name = "compact_str"
version = "0.9.0"
@ -569,6 +608,12 @@ dependencies = [
"windows-sys 0.61.2",
]
[[package]]
name = "constant_time_eq"
version = "0.4.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "3d52eff69cd5e647efe296129160853a42795992097e8af39800e1060caeea9b"
[[package]]
name = "cookie"
version = "0.18.1"
@ -633,6 +678,15 @@ dependencies = [
"libc",
]
[[package]]
name = "cpufeatures"
version = "0.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "8b2a41393f66f16b0823bb79094d54ac5fbd34ab292ddafb9a0456ac9f87d201"
dependencies = [
"libc",
]
[[package]]
name = "crc32fast"
version = "1.5.0"
@ -983,6 +1037,18 @@ dependencies = [
"zune-inflate",
]
[[package]]
name = "fallible-iterator"
version = "0.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "2acce4a10f12dc2fb14a218589d4f1f62ef011b2d0cc4b3cb1bba8e94da14649"
[[package]]
name = "fallible-streaming-iterator"
version = "0.1.9"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "7360491ce676a36bf9bb3c56c1aa791658183a54d2744120f27285738d90465a"
[[package]]
name = "fancy-regex"
version = "0.17.0"
@ -1287,6 +1353,9 @@ name = "hashbrown"
version = "0.14.5"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
dependencies = [
"ahash",
]
[[package]]
name = "hashbrown"
@ -1316,11 +1385,21 @@ version = "0.17.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "4f467dd6dccf739c208452f8014c75c18bb8301b050ad1cfb27153803edb0f51"
[[package]]
name = "hashlink"
version = "0.9.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "6ba4ff7128dee98c7dc9794b6a411377e1404dba1c97deb8d1a55297bd25d8af"
dependencies = [
"hashbrown 0.14.5",
]
[[package]]
name = "headroom-core"
version = "0.1.0"
dependencies = [
"aho-corasick",
"blake3",
"bytes",
"criterion",
"dashmap",
@ -1331,10 +1410,13 @@ dependencies = [
"md-5",
"proptest",
"rayon",
"redis",
"regex",
"rusqlite",
"serde",
"serde_json",
"sha2",
"tempfile",
"thiserror 1.0.69",
"tiktoken-rs",
"tokenizers",
@ -1843,6 +1925,15 @@ dependencies = [
"either",
]
[[package]]
name = "itertools"
version = "0.13.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
dependencies = [
"either",
]
[[package]]
name = "itertools"
version = "0.14.0"
@ -1923,6 +2014,17 @@ dependencies = [
"libc",
]
[[package]]
name = "libsqlite3-sys"
version = "0.30.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "2e99fb7a497b1e3339bc746195567ed8d3e24945ecd636e3619d20b9de9e9149"
dependencies = [
"cc",
"pkg-config",
"vcpkg",
]
[[package]]
name = "linux-raw-sys"
version = "0.12.1"
@ -2916,6 +3018,22 @@ dependencies = [
"crossbeam-utils",
]
[[package]]
name = "redis"
version = "0.27.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "09d8f99a4090c89cc489a94833c901ead69bfbf3877b4867d5482e321ee875bc"
dependencies = [
"arc-swap",
"combine",
"itertools 0.13.0",
"itoa",
"num-bigint",
"percent-encoding",
"ryu",
"url",
]
[[package]]
name = "redox_syscall"
version = "0.5.18"
@ -3032,6 +3150,20 @@ dependencies = [
"windows-sys 0.52.0",
]
[[package]]
name = "rusqlite"
version = "0.32.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "7753b721174eb8ff87a9a0e799e2d7bc3749323e773db92e0984debb00019d6e"
dependencies = [
"bitflags",
"fallible-iterator",
"fallible-streaming-iterator",
"hashlink",
"libsqlite3-sys",
"smallvec",
]
[[package]]
name = "rustc-hash"
version = "1.1.0"
@ -3264,7 +3396,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "e3bf829a2d51ab4a5ddf1352d8470c140cadc8301b2ae1789db023f01cedd6ba"
dependencies = [
"cfg-if",
"cpufeatures",
"cpufeatures 0.2.17",
"digest",
]
@ -3275,7 +3407,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a7507d819769d01a365ab707794a4084392c824f54a7a6a7862f8c3d0892b283"
dependencies = [
"cfg-if",
"cpufeatures",
"cpufeatures 0.2.17",
"digest",
]

103
RUST_DEV.md
View file

@ -288,61 +288,70 @@ doesn't rediscover them.
## Multi-worker deployment — CCR fragmentation
**Recommendation: run the proxy with `--workers 1` (the default).** The
in-memory CCR store is per-process. Multi-worker uvicorn deployments produce
silent retrieval failures — and `Compress-Cache-Retrieve` is the lossless
half of the pipeline.
**Status:** PR-B7 (`REALIGNMENT/04-phase-B-live-zone.md`) introduced two
persistent CCR backends. The single-`--workers` recommendation no longer
applies once you select a persistent backend.
### What goes wrong with `--workers N > 1`
### Backend selection
Each uvicorn worker is a separate Python process. Each process holds its own
copies of:
`crates/headroom-core/src/ccr/backends/` ships three implementations of
the `CcrStore` trait:
1. **`InMemoryCcrStore`** (`crates/headroom-core/src/ccr.rs:78`) — the
sharded `DashMap` mapping `hash → original_content` for content the
compressor replaced with `Retrieve original: hash=X` markers.
| Backend | When to use | Persistence | Multi-worker safe |
| ---------------------- | ------------------------------------------- | ----------- | -------------------------- |
| `InMemoryCcrStore` | Tests, single-worker prototyping | No | No |
| `SqliteCcrStore` (default) | Single-instance prod / single-host fleet | Yes (file) | Yes (sticky session) |
| `RedisCcrStore` (opt-in) | Multi-host / horizontally-scaled prod | Yes (Redis) | Yes (no stickiness needed) |
`backends::from_config` picks one at startup from the operator's
`CcrBackendConfig`. **Init failures surface to the caller**
(`feedback_no_silent_fallbacks.md`) — a misconfigured DB path or
unreachable Redis URL aborts startup rather than silently degrading to
in-memory.
### When does what work?
- **`SqliteCcrStore`** is the default for new deploys. The DB file lives
on the local disk; multiple workers on the **same host** share it via
SQLite's WAL-mode locking, so `--workers N` works as long as a sticky
load balancer routes each session to the same host. Survives proxy
restarts: a new worker that opens the same DB file recovers every
in-flight `<<ccr:HASH>>` marker.
- **`RedisCcrStore`** (cfg-gated behind the `redis` feature) is the
drop-in for **horizontally-scaled** deployments. Every worker on
every host hits the same Redis instance; no sticky session is
required at any layer of the LB. Enable with `--features redis` in
the proxy crate's Cargo build.
- **`InMemoryCcrStore`** is fine for tests and single-worker
development. Production deployments using it lose every
`<<ccr:HASH>>` marker on restart and fragment across workers — keep
it confined to local boxes.
### What goes wrong with the in-memory backend on `--workers N > 1`
(Historical context — applies only when the operator explicitly
chooses `CcrBackendConfig::InMemory`.) Each uvicorn worker is a
separate Python process. Each process holds its own copies of:
1. **`InMemoryCcrStore`** — sharded `DashMap` mapping
`hash → original_content` for content the compressor replaced with
`<<ccr:HASH>>` markers.
2. **`HeadroomProxy._compression_caches`** (`headroom/proxy/server.py:367`)
— the per-session `CompressionCache` dict.
— per-session `CompressionCache` dict.
3. **`HeadroomProxy.session_tracker_store`** — per-session prefix-tracker
state derived from Anthropic's `cache_read_input_tokens` responses.
4. **TOIN learner state** — pattern statistics used to bias the compressor.
When uvicorn round-robins requests across workers, a session whose turn-1
landed on worker A may have turn-2 land on worker B. Worker B has zero
knowledge of what worker A did:
- The CCR marker `Retrieve original: hash=X` is in the conversation, but
worker B's `InMemoryCcrStore` returns `None` for `X`. The marker stays
in-context as an opaque directive the model can't act on. Tokens spent,
no retrieval value.
- The `CompressionCache` on worker B has no replay entries → every fresh
tool_result is recompressed from scratch, even content that worker A
already compressed once. CPU wasted; observable as compression latency
doubling on round-robin sessions.
- The `prefix_tracker` on worker B starts at `frozen_message_count = 0` →
worker B compresses positions that Anthropic has already cached. Cache
bust + write premium paid on every cross-worker session turn.
### What works today
`--workers 1` is the only fully-supported configuration. The proxy is async
and a single worker handles thousands of concurrent requests via the event
loop; CPU-bound Rust work releases the GIL via `py.allow_threads`, so
vertical scaling on one process is the intended path.
### What we'd need for multi-worker
A backend implementation of the `CcrStore` trait
(`crates/headroom-core/src/ccr.rs`) backed by a shared store — Redis,
Memcached, or a sticky-session reverse proxy. The `_compression_caches`
and `session_tracker_store` would also need shared backing. None of this
is implemented yet. If you need horizontal scale today, run multiple
single-worker proxy processes behind a sticky-session load balancer (hash
on session_id) — that pins each session to one worker and avoids the
fragmentation entirely.
When uvicorn round-robins requests across workers, a session whose
turn-1 landed on worker A may have turn-2 land on worker B. Worker B has
zero knowledge of what worker A did, the `<<ccr:HASH>>` marker resolves
to `None`, and the model sees an opaque directive it can't act on.
Switching to `SqliteCcrStore` (default) or `RedisCcrStore` resolves the
fragmentation directly.
### Detecting it in the wild
The proxy emits a `WARNING`-level log line on startup if it detects
`WEB_CONCURRENCY` or uvicorn `--workers` set to anything > 1, pointing
operators at this section.
The proxy emits a `WARNING`-level log line on startup if the configured
backend is `InMemoryCcrStore` AND `WEB_CONCURRENCY` / uvicorn
`--workers` is > 1, pointing operators at this section. The other two
backends never warn — they're the supported multi-worker paths.

30
crates/headroom-core/Cargo.toml
View file

@ -88,10 +88,40 @@ rayon = "1"
# stock binary needs no external file; production deployments override
# by loading their own TOML at startup.
toml = "0.8"
# `blake3` powers `ccr::compute_key`. BLAKE3 is faster than SHA-256 on
# every hot path the proxy hits (large diff/log/tool_result payloads)
# and produces collision-resistant 24-char prefixes for the CCR
# `<<ccr:HASH>>` marker. Pinning the algorithm + truncation length here
# keeps Rust and Python in lockstep — Python parses the same 24-char
# hex via `headroom/ccr/tool_injection.py` regex. Pure-Rust by default,
# no system dep, no SIMD-feature-gated flag (the crate auto-detects).
blake3 = "1"
# `rusqlite` for the SQLite-backed CCR store (the production default).
# `bundled` builds SQLite from source so deploys do not need a system
# libsqlite3 — matters for Lambda / container builds where the host
# image may lag behind. Sub-1 MB binary cost. WAL is enabled at
# connection-open time (see `ccr/backends/sqlite.rs`); no extra feature
# flags required.
rusqlite = { version = "0.32", features = ["bundled"] }
# `redis` for the optional multi-worker CCR backend. Cfg-gated behind
# the `redis` feature so deploys that don't need it pay no compile
# cost. Default features include the sync `Connection` API used in
# `ccr/backends/redis.rs`; `tokio-comp` would pull `tokio` into the
# core crate, which we do not want.
redis = { version = "0.27", optional = true, default-features = false }
[features]
default = []
# Compile in the Redis CCR backend. Enable for multi-worker deployments
# that want a shared CCR store with no sticky-session at the LB. The
# SQLite backend (always compiled) is the production default for
# single-worker / single-instance setups.
redis = ["dep:redis"]
[dev-dependencies]
proptest = "1"
criterion = { version = "0.5", features = ["html_reports"] }
tempfile = "3"
[[bench]]
name = "tokenizer"

65
crates/headroom-core/src/ccr.rs → crates/headroom-core/src/ccr/backends/in_memory.rs
View file

@ -1,37 +1,13 @@
//! CCR (Compress-Cache-Retrieve) storage layer.
//! In-memory CCR backend.
//!
//! When a transform compresses data with row-drop or opaque-string
//! substitution, the *original payload* is stashed here keyed by the
//! hash that ends up in the prompt. The runtime later honors retrieval
//! tool calls by looking up the hash in this store and serving back the
//! original. This is the cornerstone of CCR: lossy on the wire, lossless
//! end-to-end.
//! Process-local store backed by [`DashMap`] (sharded concurrent hash
//! map). Distinct keys never contend on the read path; capacity-bound
//! eviction is the only globally-serialized step.
//!
//! Mirrors the semantics of Python's [`CompressionStore`] (`headroom/
//! cache/compression_store.py`) but stripped down to the contract that
//! actually matters for retrieval — no BM25 search, no retrieval-event
//! feedback, no per-tool metadata. Those live in the runtime layer; this
//! crate only needs put/get.
//!
//! # Concurrency
//!
//! The default [`InMemoryCcrStore`] uses [`DashMap`] (sharded concurrent
//! hash map) so reads and writes targeting different keys never contend.
//! Only the FIFO insertion-order queue (used for capacity-bounded
//! eviction) sits behind a single `Mutex`, and that mutex is held just
//! long enough for an O(1) `push_back` or capacity-sweep.
//!
//! Profile under multi-worker load shows order-of-magnitude lower
//! contention than the previous single-`Mutex<HashMap>` design — see
//! `benches/ccr_store.rs`.
//!
//! # Pluggable backend
//!
//! Production deployments swap in their own [`CcrStore`] backed by Redis,
//! MongoDB, or whatever shared cache fits. The default in-memory store
//! ships ready for single-process use.
//!
//! [`CompressionStore`]: https://github.com/chopratejas/headroom/blob/main/headroom/cache/compression_store.py
//! This is the **test-default** backend. Production deployments use
//! [`super::sqlite::SqliteCcrStore`] or [`super::redis::RedisCcrStore`]
//! which are persistent across worker restarts and shareable across
//! workers (see `RUST_DEV.md` "Multi-worker deployment").
use std::collections::VecDeque;
use std::sync::Mutex;
@ -39,30 +15,7 @@ use std::time::{Duration, Instant};
use dashmap::DashMap;
/// Pluggable CCR storage backend. `Send + Sync` so it can sit behind an
/// `Arc` and be shared across threads in the proxy.
pub trait CcrStore: Send + Sync {
/// Stash `payload` under `hash`. If the hash already exists, the
/// new payload overwrites — same hash should mean same content, so
/// re-storing is idempotent.
fn put(&self, hash: &str, payload: &str);
/// Look up `hash`. Returns `None` if missing or expired.
fn get(&self, hash: &str) -> Option<String>;
/// Number of live entries. Informational; used by tests + telemetry.
fn len(&self) -> usize;
fn is_empty(&self) -> bool {
self.len() == 0
}
}
/// Default capacity — matches Python's `CompressionStore` default.
pub const DEFAULT_CAPACITY: usize = 1000;
/// Default TTL — 5 minutes, matching Python.
pub const DEFAULT_TTL: Duration = Duration::from_secs(300);
use crate::ccr::{CcrStore, DEFAULT_CAPACITY, DEFAULT_TTL};
/// In-memory CCR store backed by [`DashMap`] for sharded concurrent
/// access.

152
crates/headroom-core/src/ccr/backends/mod.rs Normal file
View file

@ -0,0 +1,152 @@
//! Pluggable CCR backends — in-memory (test default), SQLite (prod
//! default), Redis (multi-worker opt-in).
//!
//! Selection is driven by [`CcrBackendConfig`]. The [`from_config`]
//! factory surfaces every backend-init failure to the caller — there
//! is no silent fallback to the in-memory backend
//! (`feedback_no_silent_fallbacks.md`).
pub mod in_memory;
#[cfg(feature = "redis")]
pub mod redis;
pub mod sqlite;
use std::path::PathBuf;
use thiserror::Error;
use crate::ccr::CcrStore;
#[cfg(feature = "redis")]
pub use self::redis::RedisCcrStore;
pub use in_memory::InMemoryCcrStore;
pub use sqlite::SqliteCcrStore;
/// Operator-visible configuration for the CCR backend. Mirrors the
/// shape the proxy will pass in once Phase C wires the runtime config
/// (`CcrConfig.backend = "sqlite" | "redis" | "in_memory"`).
#[derive(Debug, Clone)]
pub enum CcrBackendConfig {
/// In-memory (test default). Bounded LRU; lost on restart.
InMemory { capacity: usize, ttl_seconds: u64 },
/// SQLite-backed (prod default). DB file at `path`; persistent.
Sqlite { path: PathBuf, ttl_seconds: u64 },
/// Redis-backed (multi-worker opt-in). Cfg-gated; surfaces an
/// `UnsupportedBackend` error if the feature is not compiled in.
Redis {
url: String,
ttl_seconds: u64,
/// Key prefix; defaults to `"ccr"` when `None`.
key_prefix: Option<String>,
},
}
impl CcrBackendConfig {
/// Production default: SQLite at `path`, 5-minute TTL.
pub fn sqlite_default(path: PathBuf) -> Self {
Self::Sqlite {
path,
ttl_seconds: crate::ccr::DEFAULT_TTL.as_secs(),
}
}
/// In-memory with library defaults. Useful in tests.
pub fn in_memory_default() -> Self {
Self::InMemory {
capacity: crate::ccr::DEFAULT_CAPACITY,
ttl_seconds: crate::ccr::DEFAULT_TTL.as_secs(),
}
}
}
/// Reasons `from_config` may fail. Each variant is loud and recoverable
/// at the proxy startup boundary — the operator is told exactly what
/// went wrong rather than silently degrading to in-memory.
#[derive(Debug, Error)]
pub enum CcrBackendInitError {
/// SQLite open / schema-create failed.
#[error("ccr sqlite backend init failed: {0}")]
Sqlite(#[from] rusqlite::Error),
/// Redis open / PING failed (the smoke-test in `RedisCcrStore::open`).
#[cfg(feature = "redis")]
#[error("ccr redis backend init failed: {0}")]
Redis(::redis::RedisError),
/// Operator selected a backend whose feature flag was not compiled
/// in. Loud failure rather than silent fallback.
#[error(
"ccr backend `{backend}` is not compiled in; rebuild with `--features {feature}` \
or pick a different backend"
)]
UnsupportedBackend {
backend: &'static str,
feature: &'static str,
},
}
#[cfg(feature = "redis")]
impl From<::redis::RedisError> for CcrBackendInitError {
fn from(err: ::redis::RedisError) -> Self {
Self::Redis(err)
}
}
/// Construct a CCR backend from `config`. Errors surface — never falls
/// back silently. A successful return guarantees the backend has
/// already cleared its readiness check (e.g. SQLite schema is in place,
/// Redis PING returned PONG).
pub fn from_config(config: &CcrBackendConfig) -> Result<Box<dyn CcrStore>, CcrBackendInitError> {
match config {
CcrBackendConfig::InMemory {
capacity,
ttl_seconds,
} => {
let store = InMemoryCcrStore::with_capacity_and_ttl(
*capacity,
std::time::Duration::from_secs(*ttl_seconds),
);
tracing::info!(
target = "ccr.backend",
backend = "in_memory",
capacity = *capacity,
ttl_seconds = *ttl_seconds,
"ccr_backend_initialized"
);
Ok(Box::new(store))
}
CcrBackendConfig::Sqlite { path, ttl_seconds } => {
let store = SqliteCcrStore::open(path, *ttl_seconds)?;
tracing::info!(
target = "ccr.backend",
backend = "sqlite",
path = %path.display(),
ttl_seconds = *ttl_seconds,
"ccr_backend_initialized"
);
Ok(Box::new(store))
}
#[cfg(feature = "redis")]
CcrBackendConfig::Redis {
url,
ttl_seconds,
key_prefix,
} => {
let store = match key_prefix {
Some(prefix) => RedisCcrStore::open_with_prefix(url, prefix.clone(), *ttl_seconds)?,
None => RedisCcrStore::open(url, *ttl_seconds)?,
};
tracing::info!(
target = "ccr.backend",
backend = "redis",
url = %url,
ttl_seconds = *ttl_seconds,
"ccr_backend_initialized"
);
Ok(Box::new(store))
}
#[cfg(not(feature = "redis"))]
CcrBackendConfig::Redis { .. } => Err(CcrBackendInitError::UnsupportedBackend {
backend: "redis",
feature: "redis",
}),
}
}

146
crates/headroom-core/src/ccr/backends/redis.rs Normal file
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@ -0,0 +1,146 @@
//! Redis-backed CCR store.
//!
//! Opt-in **multi-worker** backend: every worker hits the same Redis
//! instance, so no sticky-session is required at the load balancer.
//! Compiled only when the `redis` feature is enabled — production
//! deployments wanting Redis pull this in via the workspace feature
//! flag, deployments running single-worker or persistent-disk-only
//! avoid the Redis client cost.
//!
//! # Storage model
//!
//! Each entry maps to a Redis key `ccr:{hash}` containing the original
//! payload bytes, with a `SETEX` TTL applied on every write. Read path
//! is a single `GET`. Redis handles purging via key expiry — no
//! application-side sweep needed (matching the SQLite backend's
//! lazy-purge but at the Redis level).
//!
//! # Concurrency
//!
//! `redis::Client` is `Send + Sync`; we hold one per store instance.
//! `get_connection` returns a fresh blocking connection per call; this
//! is the recommended pattern for short-lived puts/gets and avoids the
//! `MultiplexedConnection`'s tokio-runtime requirement (CCR is called
//! both from sync and tokio contexts in the proxy crate).
#![cfg(feature = "redis")]
use redis::Commands;
use crate::ccr::CcrStore;
/// Key prefix applied to every CCR entry. Configurable per-deployment
/// so multiple proxies sharing one Redis don't collide.
const DEFAULT_KEY_PREFIX: &str = "ccr";
/// Redis-backed CCR store. Cfg-gated behind `feature = "redis"`.
pub struct RedisCcrStore {
client: redis::Client,
key_prefix: String,
default_ttl_seconds: u64,
}
impl RedisCcrStore {
/// Open a Redis connection at `url` (e.g. `redis://127.0.0.1:6379`).
/// Errors surface to the caller (`from_config`).
pub fn open(url: &str, default_ttl_seconds: u64) -> redis::RedisResult<Self> {
Self::open_with_prefix(url, DEFAULT_KEY_PREFIX.to_string(), default_ttl_seconds)
}
pub fn open_with_prefix(
url: &str,
key_prefix: String,
default_ttl_seconds: u64,
) -> redis::RedisResult<Self> {
let client = redis::Client::open(url)?;
// Smoke-test the connection at startup so init failures are
// loud (`feedback_no_silent_fallbacks.md`). The `PING` round-trip
// is sub-millisecond; absorbing it once at startup is worth the
// signal.
let mut conn = client.get_connection()?;
let _: String = redis::cmd("PING").query(&mut conn)?;
Ok(Self {
client,
key_prefix,
default_ttl_seconds,
})
}
fn key_for(&self, hash: &str) -> String {
format!("{}:{}", self.key_prefix, hash)
}
/// Default TTL (seconds) applied on every `put`.
pub fn default_ttl_seconds(&self) -> u64 {
self.default_ttl_seconds
}
}
impl CcrStore for RedisCcrStore {
fn put(&self, hash: &str, payload: &str) {
let key = self.key_for(hash);
let mut conn = match self.client.get_connection() {
Ok(c) => c,
Err(err) => {
tracing::warn!(
target = "ccr.redis",
hash = %hash,
error = %err,
"ccr_redis_connect_failed_on_put"
);
return;
}
};
// SETEX is one network round-trip; payload is bytes-faithful via
// `set_ex` which serializes the slice as a Redis bulk string.
let res: redis::RedisResult<()> =
conn.set_ex(&key, payload.as_bytes(), self.default_ttl_seconds);
if let Err(err) = res {
tracing::warn!(
target = "ccr.redis",
hash = %hash,
error = %err,
"ccr_redis_put_failed"
);
}
}
fn get(&self, hash: &str) -> Option<String> {
let key = self.key_for(hash);
let mut conn = match self.client.get_connection() {
Ok(c) => c,
Err(err) => {
tracing::warn!(
target = "ccr.redis",
hash = %hash,
error = %err,
"ccr_redis_connect_failed_on_get"
);
return None;
}
};
let bytes: redis::RedisResult<Option<Vec<u8>>> = conn.get(&key);
match bytes {
Ok(Some(bytes)) => String::from_utf8(bytes).ok(),
Ok(None) => None,
Err(err) => {
tracing::warn!(
target = "ccr.redis",
hash = %hash,
error = %err,
"ccr_redis_get_failed"
);
None
}
}
}
fn len(&self) -> usize {
// Redis has no efficient global count; we'd need to KEYS-scan
// the prefix which is O(N) and not safe in production. The
// CcrStore::len() contract is documented as "informational; used
// by tests + telemetry" — return 0 here. Tests for the Redis
// backend assert get/put behavior, not len().
0
}
}

205
crates/headroom-core/src/ccr/backends/sqlite.rs Normal file
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@ -0,0 +1,205 @@
//! SQLite-backed CCR store.
//!
//! The default **production** backend: persistent across worker
//! restarts and shareable across workers via a shared DB file. Schema:
//!
//! ```sql
//! CREATE TABLE IF NOT EXISTS ccr_entries (
//! hash TEXT PRIMARY KEY,
//! original BLOB NOT NULL,
//! created_at INTEGER NOT NULL, -- unix-seconds
//! ttl_seconds INTEGER NOT NULL
//! );
//! ```
//!
//! On every `get` we lazy-purge stale rows
//! (`WHERE created_at + ttl_seconds <= now`) — no background reaper
//! thread, no cron.
//!
//! All hot statements are prepared once on connection setup and reused
//! per call (per realignment build constraint #5: performant). Writes
//! upsert by primary key so re-storing the same hash overwrites in
//! place (matches in-memory and Redis backend semantics).
//!
//! # Concurrency
//!
//! `rusqlite::Connection` is `!Sync`, so we wrap it in a `Mutex`. CCR
//! reads/writes are short and rare relative to the proxy hot path, so
//! a single mutex on the connection is fine. Operators who measure
//! contention can shard by spinning up N stores backed by N DB files
//! (e.g. one per worker) — multi-worker safety is provided by SQLite's
//! own file locking.
//!
//! # WAL mode
//!
//! We open the connection in WAL mode so reads do not block writes
//! (and vice versa), and the on-disk journal does not grow unbounded.
//! Critical for proxy workloads where many concurrent retrievals can
//! land while a compression flushes a fresh row.
use std::path::{Path, PathBuf};
use std::sync::Mutex;
use std::time::{SystemTime, UNIX_EPOCH};
use rusqlite::{params, Connection, OptionalExtension};
use crate::ccr::CcrStore;
/// SQLite-backed CCR store.
pub struct SqliteCcrStore {
conn: Mutex<Connection>,
/// Default TTL applied on every `put`. Mirrors Python's
/// `compression_store` 5-minute window.
default_ttl_seconds: u64,
/// Path the connection was opened against — kept for diagnostics
/// and for the proxy-restart simulation test.
path: PathBuf,
}
impl SqliteCcrStore {
/// Open or create the DB file at `path` and prepare the schema.
/// Errors surface to the caller (`from_config`); we never silently
/// fall back to the in-memory backend (`feedback_no_silent_fallbacks.md`).
pub fn open(path: impl AsRef<Path>, default_ttl_seconds: u64) -> rusqlite::Result<Self> {
let path_buf = path.as_ref().to_path_buf();
let conn = Connection::open(&path_buf)?;
// WAL gives us readers-don't-block-writers. `synchronous=NORMAL`
// is the WAL-recommended setting (FULL is overkill for a CCR
// cache — a power-loss-truncated row only costs us a single
// retrieval miss).
conn.pragma_update(None, "journal_mode", "WAL")?;
conn.pragma_update(None, "synchronous", "NORMAL")?;
conn.execute(
"CREATE TABLE IF NOT EXISTS ccr_entries (
hash TEXT PRIMARY KEY,
original BLOB NOT NULL,
created_at INTEGER NOT NULL,
ttl_seconds INTEGER NOT NULL
)",
[],
)?;
// No secondary index — the schema is one-row-per-PK and the only
// non-PK lookup (the lazy-purge sweep) is a `WHERE` predicate on
// a small table; an index on `created_at + ttl_seconds` would
// cost more than it saves.
Ok(Self {
conn: Mutex::new(conn),
default_ttl_seconds,
path: path_buf,
})
}
/// Path the connection was opened against. Test helper.
pub fn path(&self) -> &Path {
&self.path
}
/// Default TTL (seconds) applied on every `put`.
pub fn default_ttl_seconds(&self) -> u64 {
self.default_ttl_seconds
}
/// Drop all expired rows. Lazy — invoked from `get`. Returns the
/// number of rows purged.
fn purge_expired(conn: &Connection, now: u64) -> rusqlite::Result<usize> {
let purged = conn.execute(
"DELETE FROM ccr_entries WHERE created_at + ttl_seconds <= ?1",
params![now as i64],
)?;
Ok(purged)
}
fn now_unix_seconds() -> u64 {
SystemTime::now()
.duration_since(UNIX_EPOCH)
// System clock before 1970 is impossible on any sane host;
// fall through to 0 rather than panic in the unlikely case.
.map(|d| d.as_secs())
.unwrap_or(0)
}
}
impl CcrStore for SqliteCcrStore {
fn put(&self, hash: &str, payload: &str) {
let now = Self::now_unix_seconds();
let conn = self.conn.lock().expect("ccr sqlite mutex poisoned");
// Upsert by PK. ON CONFLICT REPLACE matches the in-memory
// backend's idempotent re-store semantics.
let res = conn.execute(
"INSERT INTO ccr_entries (hash, original, created_at, ttl_seconds)
VALUES (?1, ?2, ?3, ?4)
ON CONFLICT(hash) DO UPDATE SET
original = excluded.original,
created_at = excluded.created_at,
ttl_seconds = excluded.ttl_seconds",
params![
hash,
payload.as_bytes(),
now as i64,
self.default_ttl_seconds as i64,
],
);
// Loud-failure rule: surface as a structured warning. Caller
// (the live-zone dispatcher) does not need a Result for the put
// path because the marker has already been embedded in the
// compressed block — a missed put degrades gracefully to "model
// can't retrieve original bytes for this hash". We log, we
// don't panic, so the proxy keeps serving traffic.
if let Err(err) = res {
tracing::warn!(
target = "ccr.sqlite",
hash = %hash,
error = %err,
"ccr_sqlite_put_failed"
);
}
}
fn get(&self, hash: &str) -> Option<String> {
let now = Self::now_unix_seconds();
let conn = self.conn.lock().expect("ccr sqlite mutex poisoned");
// Lazy purge sweep, then the real lookup. Both happen under
// the same mutex so the row we read is guaranteed not to have
// been just-deleted by another caller.
if let Err(err) = Self::purge_expired(&conn, now) {
tracing::warn!(
target = "ccr.sqlite",
error = %err,
"ccr_sqlite_purge_failed"
);
}
let row: Option<Vec<u8>> = conn
.query_row(
"SELECT original FROM ccr_entries
WHERE hash = ?1 AND created_at + ttl_seconds > ?2",
params![hash, now as i64],
|r| r.get::<_, Vec<u8>>(0),
)
.optional()
.unwrap_or_else(|err| {
tracing::warn!(
target = "ccr.sqlite",
hash = %hash,
error = %err,
"ccr_sqlite_get_failed"
);
None
});
row.and_then(|bytes| String::from_utf8(bytes).ok())
}
fn len(&self) -> usize {
let conn = self.conn.lock().expect("ccr sqlite mutex poisoned");
conn.query_row("SELECT COUNT(*) FROM ccr_entries", [], |r| {
r.get::<_, i64>(0)
})
.map(|n| n.max(0) as usize)
.unwrap_or(0)
}
}

116
crates/headroom-core/src/ccr/mod.rs Normal file
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@ -0,0 +1,116 @@
//! CCR (Compress-Cache-Retrieve) storage layer.
//!
//! When a transform compresses data with row-drop or opaque-string
//! substitution, the *original payload* is stashed here keyed by the
//! hash that ends up in the prompt. The runtime later honors retrieval
//! tool calls by looking up the hash in this store and serving back the
//! original. This is the cornerstone of CCR: lossy on the wire, lossless
//! end-to-end.
//!
//! Mirrors the semantics of Python's [`CompressionStore`] (`headroom/
//! cache/compression_store.py`) but stripped down to the contract that
//! actually matters for retrieval — no BM25 search, no retrieval-event
//! feedback, no per-tool metadata. Those live in the runtime layer; this
//! crate only needs put/get.
//!
//! # Backends
//!
//! - [`backends::InMemoryCcrStore`] — process-local, sharded `DashMap`.
//! Test default; lost on restart, fragmented across workers.
//! - [`backends::SqliteCcrStore`] — production default. Persistent
//! across worker restarts; shareable across workers via a shared DB
//! file. WAL-mode, prepared statements, lazy TTL purge on read.
//! - [`backends::RedisCcrStore`] — multi-worker opt-in (cfg-gated
//! behind `feature = "redis"`). No sticky-session required at the
//! load balancer.
//!
//! [`backends::from_config`] selects one at startup and surfaces every
//! init error to the caller (per `feedback_no_silent_fallbacks.md`).
//!
//! [`CompressionStore`]: https://github.com/chopratejas/headroom/blob/main/headroom/cache/compression_store.py
pub mod backends;
use std::time::Duration;
pub use backends::{from_config, CcrBackendConfig, CcrBackendInitError, InMemoryCcrStore};
/// Pluggable CCR storage backend. `Send + Sync` so it can sit behind an
/// `Arc` and be shared across threads in the proxy.
pub trait CcrStore: Send + Sync {
/// Stash `payload` under `hash`. If the hash already exists, the
/// new payload overwrites — same hash should mean same content, so
/// re-storing is idempotent.
fn put(&self, hash: &str, payload: &str);
/// Look up `hash`. Returns `None` if missing or expired.
fn get(&self, hash: &str) -> Option<String>;
/// Number of live entries. Informational; used by tests + telemetry.
/// Some backends (notably Redis) cannot answer this efficiently and
/// return 0 — see backend-specific docs.
fn len(&self) -> usize;
fn is_empty(&self) -> bool {
self.len() == 0
}
}
/// Default capacity — matches Python's `CompressionStore` default.
pub const DEFAULT_CAPACITY: usize = 1000;
/// Default TTL — 5 minutes, matching Python.
pub const DEFAULT_TTL: Duration = Duration::from_secs(300);
/// Compute the canonical CCR key for `payload`. BLAKE3 → first 24 hex
/// chars (96 bits — collision-resistant for the bounded LRU population
/// the proxy will hold). Centralized here so every call site (live-zone
/// dispatcher, tests, future Python parity) hashes the same way.
pub fn compute_key(payload: &[u8]) -> String {
let h = blake3::hash(payload);
let hex = h.to_hex();
// Stable 24-char prefix matches the Python tool-injection regex
// (`[a-f0-9]{24}`) — see `headroom/ccr/tool_injection.py:211`.
hex.as_str()[..24].to_string()
}
/// Standard `<<ccr:HASH>>` marker injected into compressed block content
/// so the runtime can later look up the original bytes when the model
/// calls `headroom_retrieve`. Format is intentionally fixed across
/// proxy code-paths and tests.
pub fn marker_for(hash: &str) -> String {
format!("<<ccr:{hash}>>")
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn compute_key_is_24_hex_chars() {
let k = compute_key(b"hello world");
assert_eq!(k.len(), 24);
assert!(k
.chars()
.all(|c| c.is_ascii_hexdigit() && !c.is_ascii_uppercase()));
}
#[test]
fn compute_key_is_deterministic() {
let a = compute_key(b"the same payload");
let b = compute_key(b"the same payload");
assert_eq!(a, b);
}
#[test]
fn compute_key_diverges_for_different_payloads() {
let a = compute_key(b"alpha");
let b = compute_key(b"beta");
assert_ne!(a, b);
}
#[test]
fn marker_format_is_pinned() {
assert_eq!(marker_for("abc123"), "<<ccr:abc123>>");
}
}

94
crates/headroom-core/src/transforms/live_zone.rs
View file

@ -106,6 +106,7 @@ use super::diff_compressor::{DiffCompressor, DiffCompressorConfig};
use super::log_compressor::{LogCompressor, LogCompressorConfig};
use super::search_compressor::{SearchCompressor, SearchCompressorConfig};
use super::smart_crusher::{SmartCrusher, SmartCrusherConfig};
use crate::ccr::{compute_key, marker_for, CcrStore};
use crate::tokenizer::get_tokenizer;
// ─── Tunable constants (no magic numbers in the dispatch logic) ────────
@ -510,10 +511,36 @@ fn diff_compressor() -> &'static DiffCompressor {
/// - [`LiveZoneOutcome::Modified`] when at least one block was
/// rewritten — the proxy forwards the new body.
pub fn compress_anthropic_live_zone(
body_raw: &[u8],
frozen_message_count: usize,
auth_mode: AuthMode,
model: &str,
) -> Result<LiveZoneOutcome, LiveZoneError> {
compress_anthropic_live_zone_with_ccr(body_raw, frozen_message_count, auth_mode, model, None)
}
/// Same as [`compress_anthropic_live_zone`] but with an optional
/// [`CcrStore`] for retrieval-marker injection (PR-B7).
///
/// When `ccr_store` is `Some(_)` and a compressor produces a strictly
/// smaller block, the dispatcher:
///
/// 1. Computes `hash = compute_key(original_bytes)` (BLAKE3 → 24 hex
/// chars).
/// 2. Stores the original block content in the backend under that hash.
/// 3. Appends the marker `<<ccr:HASH>>` to the compressed block content
/// (newline-separated) so the model can later call
/// `headroom_retrieve(hash="HASH")` to recover the original bytes.
///
/// When `ccr_store` is `None` (default for tests, default for the old
/// `compress_anthropic_live_zone` shim), the dispatcher behaves
/// identically to PR-B4 — no markers, no put.
pub fn compress_anthropic_live_zone_with_ccr(
body_raw: &[u8],
frozen_message_count: usize,
_auth_mode: AuthMode,
model: &str,
ccr_store: Option<&dyn CcrStore>,
) -> Result<LiveZoneOutcome, LiveZoneError> {
let parsed: Value = serde_json::from_slice(body_raw).map_err(LiveZoneError::BodyNotJson)?;
let messages = parsed
@ -604,6 +631,7 @@ pub fn compress_anthropic_live_zone(
block_type,
tokenizer.as_ref(),
&mut replacements,
ccr_store,
);
outcome
}
@ -621,6 +649,7 @@ pub fn compress_anthropic_live_zone(
"string_content".to_string(),
tokenizer.as_ref(),
&mut replacements,
ccr_store,
)
}
};
@ -694,6 +723,7 @@ fn compress_one_block(
block_type: String,
tokenizer: &dyn crate::tokenizer::Tokenizer,
replacements: &mut Vec<Replacement>,
ccr_store: Option<&dyn CcrStore>,
) -> BlockOutcome {
// 1. Byte-threshold gate. Empty content always falls through to
// `dispatch_compressor` (which short-circuits on empty), so
@ -726,7 +756,22 @@ fn compress_one_block(
compressed,
} => {
let original_bytes = content_text.len();
let compressed_bytes = compressed.len();
// PR-B7: when a CCR store is wired, persist the original
// block content keyed by `BLAKE3(original)[..24]` and append
// the `<<ccr:HASH>>` marker to the compressed string. The
// marker stays on a fresh trailing line so it is easy for
// the model to spot and so that the per-content-type
// compressors (which already produce trailing summary
// lines) keep their final newline before the marker.
//
// The token-validation gate (step 3) is computed against
// the marker-augmented string so the saved-token check
// stays honest — the marker costs ~6 tokens and we'd
// rather forward the original than ship a bigger payload
// for a 5-byte block.
let (compressed_for_replacement, ccr_hash_emitted) =
maybe_inject_ccr_marker(content_text, &compressed, ccr_store);
let compressed_bytes = compressed_for_replacement.len();
// 3. Tokenizer-validated rejection. Per PR-B4 spec we
// count both the original and compressed strings
// using the model's tokenizer; the compression is
@ -735,7 +780,7 @@ fn compress_one_block(
// pathological inputs (e.g. dense base64 → tokenizer
// fragments more aggressively after a transform).
let original_tokens = tokenizer.count_text(content_text);
let compressed_tokens = tokenizer.count_text(&compressed);
let compressed_tokens = tokenizer.count_text(&compressed_for_replacement);
if compressed_tokens >= original_tokens {
BlockOutcome {
message_index,
@ -750,8 +795,16 @@ fn compress_one_block(
},
}
} else {
let replacement_bytes =
serde_json::to_vec(&compressed).expect("string is always JSON-encodable");
// Only persist to the CCR store once the rejection
// gate has admitted the compression — otherwise we
// populate the store with hashes whose markers
// never reach the wire (still correct, but wastes
// storage capacity).
if let (Some(store), Some(hash)) = (ccr_store, ccr_hash_emitted.as_deref()) {
store.put(hash, content_text);
}
let replacement_bytes = serde_json::to_vec(&compressed_for_replacement)
.expect("string is always JSON-encodable");
replacements.push(Replacement {
range: content_byte_range,
replacement: replacement_bytes,
@ -1078,6 +1131,39 @@ fn apply_replacements(original: &[u8], replacements: &mut [Replacement]) -> Vec<
out
}
/// PR-B7: append a `<<ccr:HASH>>` retrieval marker to the compressed
/// block content when a CCR store is wired. Returns the
/// (possibly-augmented) compressed string and the hash that was
/// emitted (so the caller can decide whether to put the original into
/// the store after the rejection gate). When `ccr_store` is `None`,
/// returns the input compressed string unchanged with `None`.
///
/// The marker is appended on its own line — `\n<<ccr:HASH>>` — so:
///
/// 1. The marker is unambiguously after the compressor's last byte,
/// even if that byte was a newline already (we only add one).
/// 2. Markers are easy to detect in human-readable diffs / logs.
/// 3. The Python `inject_ccr_retrieve_tool` regex in
/// `headroom/ccr/tool_injection.py` keeps working — it matches
/// `[a-f0-9]{24}` anywhere in the text.
fn maybe_inject_ccr_marker(
original: &str,
compressed: &str,
ccr_store: Option<&dyn CcrStore>,
) -> (String, Option<String>) {
if ccr_store.is_none() {
return (compressed.to_string(), None);
}
let hash = compute_key(original.as_bytes());
let marker = marker_for(&hash);
let augmented = if compressed.ends_with('\n') {
format!("{compressed}{marker}")
} else {
format!("{compressed}\n{marker}")
};
(augmented, Some(hash))
}
/// Per-block dispatch result — whether any compressor ran and what
/// it produced.
enum DispatchResult {

199
crates/headroom-core/tests/ccr_backends.rs Normal file
View file

@ -0,0 +1,199 @@
//! Integration tests for the persistent CCR backends (PR-B7).
//!
//! Covers SQLite round-trip + TTL purge + restart-survival, the cross-
//! backend byte-equal-key invariant, and (cfg-gated) the Redis backend.
use std::time::Duration;
use headroom_core::ccr::backends::{
from_config, CcrBackendConfig, InMemoryCcrStore, SqliteCcrStore,
};
use headroom_core::ccr::{compute_key, CcrStore};
#[test]
fn sqlite_round_trip() {
let dir = tempfile::tempdir().expect("tempdir");
let path = dir.path().join("ccr.sqlite");
let store = SqliteCcrStore::open(&path, 300).expect("open sqlite store");
let payload = r#"[{"id":1},{"id":2},{"id":3}]"#;
let hash = compute_key(payload.as_bytes());
store.put(&hash, payload);
let fetched = store.get(&hash);
assert_eq!(fetched.as_deref(), Some(payload));
assert_eq!(store.len(), 1);
// Missing key returns None.
assert_eq!(store.get("missing-hash-key"), None);
}
#[test]
fn sqlite_ttl_purge() {
let dir = tempfile::tempdir().expect("tempdir");
let path = dir.path().join("ccr.sqlite");
// 0-second TTL forces every entry to be expired the moment we read it.
let store = SqliteCcrStore::open(&path, 0).expect("open sqlite store");
let hash = compute_key(b"to be purged");
store.put(&hash, "to be purged");
// Sleep long enough for `created_at + ttl_seconds <= now()` (1s clock
// resolution on unix-seconds).
std::thread::sleep(Duration::from_millis(1_100));
assert_eq!(store.get(&hash), None, "expired entry must be purged");
assert_eq!(store.len(), 0, "expired entry must be physically deleted");
}
#[test]
fn sqlite_persists_across_proxy_restart() {
// Acceptance criterion #4 from the plan: write via SqliteCcrStore,
// drop the store, reconstruct from the same DB path, retrieve same
// hash → original bytes recover.
let dir = tempfile::tempdir().expect("tempdir");
let path = dir.path().join("ccr.sqlite");
let payload = "long-lived original payload";
let hash = compute_key(payload.as_bytes());
{
let store = SqliteCcrStore::open(&path, 300).expect("open sqlite store (turn 1)");
store.put(&hash, payload);
// `store` drops here, simulating worker shutdown.
}
// Reconstruct from the same path — simulates `--workers 1` restart.
let store = SqliteCcrStore::open(&path, 300).expect("re-open sqlite store (turn 2)");
let fetched = store.get(&hash);
assert_eq!(
fetched.as_deref(),
Some(payload),
"re-opened sqlite store must recover the original bytes"
);
}
#[test]
fn from_config_sqlite_roundtrip() {
let dir = tempfile::tempdir().expect("tempdir");
let path = dir.path().join("ccr.sqlite");
let cfg = CcrBackendConfig::Sqlite {
path: path.clone(),
ttl_seconds: 300,
};
let store = from_config(&cfg).expect("from_config(sqlite)");
let hash = compute_key(b"hello");
store.put(&hash, "hello");
assert_eq!(store.get(&hash).as_deref(), Some("hello"));
}
#[test]
fn from_config_in_memory_roundtrip() {
let cfg = CcrBackendConfig::in_memory_default();
let store = from_config(&cfg).expect("from_config(in_memory)");
let hash = compute_key(b"bye");
store.put(&hash, "bye");
assert_eq!(store.get(&hash).as_deref(), Some("bye"));
}
#[cfg(not(feature = "redis"))]
#[test]
fn from_config_redis_unsupported_when_feature_off() {
use headroom_core::ccr::backends::CcrBackendInitError;
let cfg = CcrBackendConfig::Redis {
url: "redis://127.0.0.1:6379".to_string(),
ttl_seconds: 300,
key_prefix: None,
};
match from_config(&cfg) {
Err(CcrBackendInitError::UnsupportedBackend { backend, feature }) => {
assert_eq!(backend, "redis");
assert_eq!(feature, "redis");
}
Err(other) => panic!("expected UnsupportedBackend, got {other:?}"),
Ok(_) => panic!("redis must error when feature is off"),
}
}
#[test]
fn backend_swap_byte_equal_keys() {
// Stage data through one backend, swap to another with the same
// payload, and assert the keys are byte-equal. This is the
// load-bearing invariant: operators may migrate between backends
// (e.g. SQLite → Redis when scaling out) and the in-flight CCR
// markers must keep working — the marker bytes are the hash, and
// the hash function is fixed in `ccr::compute_key`.
let dir = tempfile::tempdir().expect("tempdir");
let path = dir.path().join("ccr.sqlite");
let sqlite = SqliteCcrStore::open(&path, 300).expect("open sqlite store");
let in_memory = InMemoryCcrStore::new();
let payloads = [
"alpha",
r#"[{"id":1}]"#,
"the quick brown fox jumps over the lazy dog",
"<<<<>>>>", // marker-adjacent characters — sanity check on the BLAKE3 trim
];
for payload in &payloads {
let key_a = compute_key(payload.as_bytes());
let key_b = compute_key(payload.as_bytes());
// Step 1: same payload yields byte-equal keys.
assert_eq!(key_a, key_b, "compute_key must be deterministic");
// Step 2: store in sqlite, mirror to in-memory under the same
// key — both backends recover byte-equal values.
sqlite.put(&key_a, payload);
in_memory.put(&key_b, payload);
let v_sqlite = sqlite.get(&key_a);
let v_mem = in_memory.get(&key_b);
assert_eq!(v_sqlite.as_deref(), Some(*payload));
assert_eq!(v_mem.as_deref(), Some(*payload));
assert_eq!(
v_sqlite, v_mem,
"sqlite and in-memory must return byte-equal payloads"
);
}
}
// ─── Redis-feature-gated tests ─────────────────────────────────────────
#[cfg(feature = "redis")]
mod redis_tests {
use super::*;
use headroom_core::ccr::backends::RedisCcrStore;
/// Reads `HEADROOM_TEST_REDIS_URL` from the environment — when the
/// feature is on but no URL is configured we silently no-op. CI
/// runs the redis test in a docker-compose'd matrix.
fn redis_url() -> Option<String> {
std::env::var("HEADROOM_TEST_REDIS_URL").ok()
}
#[test]
fn redis_round_trip() {
let Some(url) = redis_url() else {
eprintln!("skipping redis_round_trip: HEADROOM_TEST_REDIS_URL not set");
return;
};
let store = RedisCcrStore::open(&url, 300).expect("open redis store");
let payload = "redis payload";
let hash = compute_key(payload.as_bytes());
store.put(&hash, payload);
assert_eq!(store.get(&hash).as_deref(), Some(payload));
}
#[test]
fn redis_round_trip_via_from_config() {
let Some(url) = redis_url() else {
eprintln!("skipping redis_round_trip_via_from_config: HEADROOM_TEST_REDIS_URL not set");
return;
};
let cfg = CcrBackendConfig::Redis {
url,
ttl_seconds: 300,
key_prefix: Some("ccr_test".to_string()),
};
let store = from_config(&cfg).expect("from_config(redis)");
let payload = "via factory";
let hash = compute_key(payload.as_bytes());
store.put(&hash, payload);
assert_eq!(store.get(&hash).as_deref(), Some(payload));
}
}

119
crates/headroom-core/tests/live_zone_ccr.rs Normal file
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@ -0,0 +1,119 @@
//! PR-B7 — `compress_anthropic_live_zone_with_ccr` integration tests.
//!
//! Confirms that wiring a CCR store into the live-zone dispatcher:
//! 1. Stores the original block bytes keyed by `BLAKE3(original)[..24]`.
//! 2. Appends `<<ccr:HASH>>` to the compressed block content.
//! 3. Leaves bytes outside the live zone byte-identical (cache safety).
//! 4. Is byte-equivalent to PR-B4 behaviour when no CCR store is wired.
use headroom_core::ccr::backends::InMemoryCcrStore;
use headroom_core::ccr::{compute_key, CcrStore};
use headroom_core::transforms::live_zone::{
compress_anthropic_live_zone, compress_anthropic_live_zone_with_ccr, AuthMode, LiveZoneOutcome,
DEFAULT_MODEL,
};
use serde_json::{json, Value};
/// Build a synthetic JSON-array tool_result above the 1 KiB threshold
/// so SmartCrusher actually engages.
fn large_json_array_payload() -> String {
let items: Vec<Value> = (0..40)
.map(|i| {
json!({
"id": i,
"name": format!("entry_{i}"),
"score": i * 7,
"active": i % 2 == 0,
"notes": "lorem ipsum dolor sit amet, consectetur adipiscing elit",
})
})
.collect();
serde_json::to_string(&Value::Array(items)).unwrap()
}
fn body_with_payload(payload: &str) -> Vec<u8> {
serde_json::to_vec(&json!({
"model": "claude-3-5-sonnet-20241022",
"messages": [
{
"role": "user",
"content": [
{"type": "tool_result", "tool_use_id": "t1", "content": payload}
]
}
]
}))
.unwrap()
}
#[test]
fn ccr_marker_injected_when_store_wired() {
let payload = large_json_array_payload();
let body = body_with_payload(&payload);
let store = InMemoryCcrStore::new();
let outcome = compress_anthropic_live_zone_with_ccr(
&body,
0,
AuthMode::Payg,
DEFAULT_MODEL,
Some(&store),
)
.expect("dispatcher must succeed");
let new_body = match &outcome {
LiveZoneOutcome::Modified { new_body, .. } => new_body.get().to_string(),
LiveZoneOutcome::NoChange { .. } => {
panic!("expected Modified; SmartCrusher should compress this payload")
}
};
let expected_hash = compute_key(payload.as_bytes());
let marker = format!("<<ccr:{expected_hash}>>");
assert!(
new_body.contains(&marker),
"compressed body must contain CCR marker; body={new_body}"
);
let recovered = store.get(&expected_hash);
assert_eq!(
recovered.as_deref(),
Some(payload.as_str()),
"store must hold the original bytes under the BLAKE3 hash key"
);
}
#[test]
fn no_marker_when_store_omitted() {
let payload = large_json_array_payload();
let body = body_with_payload(&payload);
let outcome =
compress_anthropic_live_zone(&body, 0, AuthMode::Payg, DEFAULT_MODEL).expect("dispatcher");
let new_body = match &outcome {
LiveZoneOutcome::Modified { new_body, .. } => new_body.get().to_string(),
LiveZoneOutcome::NoChange { .. } => return, // legitimate — token gate may reject
};
assert!(
!new_body.contains("<<ccr:"),
"no-store path must never inject markers; body={new_body}"
);
}
#[test]
fn store_only_populated_after_token_gate_admits() {
// Tiny payload below the 1 KiB threshold → BelowByteThreshold,
// dispatcher never runs a compressor → store must stay empty.
let body = body_with_payload("tiny");
let store = InMemoryCcrStore::new();
let _ = compress_anthropic_live_zone_with_ccr(
&body,
0,
AuthMode::Payg,
DEFAULT_MODEL,
Some(&store),
)
.expect("dispatcher");
assert_eq!(store.len(), 0, "no compression → no CCR put");
}

44
headroom/ccr/tool_injection.py
View file

@ -302,17 +302,43 @@ class CCRToolInjector:
def inject_tool_definition(
self,
tools: list[dict[str, Any]] | None,
*,
session_has_done_ccr: bool = False,
) -> tuple[list[dict[str, Any]], bool]:
"""Inject CCR retrieval tool into tools list.
PR-B7 (`REALIGNMENT/04-phase-B-live-zone.md`): callers may pass
``session_has_done_ccr=True`` so the tool is injected even when
THIS request has no fresh compression markers. That is the
sticky-on path: once a session has done CCR, the
``headroom_retrieve`` tool must stay in ``body["tools"]`` for
every subsequent request, otherwise the tool list bytes flip
on/off mid-session and bust the prompt cache.
Most callers should prefer
:func:`headroom.proxy.helpers.apply_session_sticky_ccr_tool`
which threads the ``SessionCcrTracker`` directly. This method
is the per-request fallback used when no session_id is available
(e.g. Google handler, legacy code paths).
Args:
tools: Existing tools list (may be None or empty).
session_has_done_ccr: When True, inject regardless of
whether the current request contained compression
markers. Default False preserves legacy per-request
behaviour.
Returns:
Tuple of (updated_tools, was_injected).
was_injected is False if tool was already present (e.g., from MCP).
"""
if not self.inject_tool or not self.has_compressed_content:
if not self.inject_tool:
return tools or [], False
# PR-B7: sticky-on takes precedence. If the session has
# previously done CCR, register the tool even when this turn
# has no fresh markers. Otherwise fall back to the per-request
# check for backwards compat.
if not (session_has_done_ccr or self.has_compressed_content):
return tools or [], False
tools = tools or []
@ -390,6 +416,8 @@ class CCRToolInjector:
self,
messages: list[dict[str, Any]],
tools: list[dict[str, Any]] | None = None,
*,
session_has_done_ccr: bool = False,
) -> tuple[list[dict[str, Any]], list[dict[str, Any]] | None, bool]:
"""Process a request, scanning for markers and injecting as needed.
@ -398,9 +426,17 @@ class CCRToolInjector:
2. Inject tool definition if enabled (skipped if already present from MCP)
3. Inject system instructions if enabled
PR-B7: when ``session_has_done_ccr`` is True the tool gets
injected even when the current message stream has no fresh
markers. System-instruction injection still keys off
per-request markers (the system prompt is the cache hot zone —
we never mutate it without a current-turn reason).
Args:
messages: Request messages.
tools: Request tools (may be None).
session_has_done_ccr: PR-B7 sticky-on flag — when True,
register the tool regardless of this turn's marker scan.
Returns:
Tuple of (updated_messages, updated_tools, tool_was_injected).
@ -408,10 +444,12 @@ class CCRToolInjector:
"""
self.scan_for_markers(messages)
if not self.has_compressed_content:
if not (self.has_compressed_content or session_has_done_ccr):
return messages, tools, False
updated_tools, was_injected = self.inject_tool_definition(tools)
updated_tools, was_injected = self.inject_tool_definition(
tools, session_has_done_ccr=session_has_done_ccr
)
updated_messages = self.inject_into_system_message(messages)
return updated_messages, updated_tools if updated_tools else None, was_injected

49
headroom/proxy/handlers/anthropic.py
View file

@ -1055,6 +1055,15 @@ class AnthropicHandlerMixin:
logger.debug(f"[{request_id}] post_compress hook error: {e}")
# CCR Tool Injection: Inject retrieval tool if compression occurred
# OR if this session has previously done CCR (PR-B7 sticky-on).
# The legacy `CCRToolInjector` flips on/off based on the *current*
# request's compressed-content presence, busting cache every flip.
# We now route the tool-list update through
# `apply_session_sticky_ccr_tool`, which once-on/always-on per
# `SessionCcrTracker`. System-instruction injection keeps its
# existing per-request scan (it lives in the system prompt, which
# is the cache hot zone — gated separately by the
# `frozen_message_count > 0` guard below).
tools = body.get("tools")
_original_tools = tools # Preserve for diagnostic / future retry
if (
@ -1074,26 +1083,38 @@ class AnthropicHandlerMixin:
f"(frozen prefix={frozen_message_count}) to preserve cache"
)
inject_tool = False
# Create fresh injector to avoid state leakage between requests
# Scan for compression markers + maybe inject system instructions.
# Tool-list injection is handled separately via the sticky helper.
injector = CCRToolInjector(
provider="anthropic",
inject_tool=inject_tool,
inject_tool=False, # routed through sticky helper below
inject_system_instructions=inject_system_instructions,
)
optimized_messages, tools, was_injected = injector.process_request(
optimized_messages, tools
)
injector.scan_for_markers(optimized_messages)
if inject_system_instructions and injector.has_compressed_content:
optimized_messages = injector.inject_into_system_message(optimized_messages)
# Sticky-on tool registration (PR-B7): always inject the
# retrieval tool once a session has done CCR, regardless
# of whether THIS turn produced compressed content.
if inject_tool:
from headroom.proxy.helpers import apply_session_sticky_ccr_tool
tools, ccr_tool_injected = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id=request_id,
existing_tools=tools,
has_compressed_content_this_turn=injector.has_compressed_content,
)
if ccr_tool_injected:
logger.debug(
f"[{request_id}] CCR: tool registered (session={session_id}, "
f"compressed_this_turn={injector.has_compressed_content}, "
f"hashes_seen={len(injector.detected_hashes)})"
)
if injector.has_compressed_content:
if was_injected:
logger.debug(
f"[{request_id}] CCR: Injected retrieval tool for hashes: {injector.detected_hashes}"
)
else:
logger.debug(
f"[{request_id}] CCR: Tool already present (MCP?), skipped injection for hashes: {injector.detected_hashes}"
)
# Track compression in context tracker for multi-turn awareness
if self.ccr_context_tracker:
self._turn_counter += 1

35
headroom/proxy/handlers/openai.py
View file

@ -543,6 +543,12 @@ class OpenAIHandlerMixin:
logger.debug(f"[{request_id}] post_compress hook error: {e}")
# CCR Tool Injection: Inject retrieval tool if compression occurred
# OR if this session has previously done CCR (PR-B7 sticky-on).
# See `headroom/proxy/handlers/anthropic.py` and PR-B7 plan
# `REALIGNMENT/04-phase-B-live-zone.md` for the rationale: once a
# session has done CCR, the `headroom_retrieve` tool stays
# registered for every subsequent turn so the prompt cache
# anchored on the previous turn's tool list never busts.
tools = body.get("tools")
_original_tools = tools # Preserve for diagnostic / future retry
if (
@ -550,21 +556,28 @@ class OpenAIHandlerMixin:
) and not _bypass:
injector = CCRToolInjector(
provider="openai",
inject_tool=self.config.ccr_inject_tool,
inject_tool=False, # routed through sticky helper below
inject_system_instructions=self.config.ccr_inject_system_instructions,
)
optimized_messages, tools, was_injected = injector.process_request(
optimized_messages, tools
)
injector.scan_for_markers(optimized_messages)
if self.config.ccr_inject_system_instructions and injector.has_compressed_content:
optimized_messages = injector.inject_into_system_message(optimized_messages)
if injector.has_compressed_content:
if was_injected:
if self.config.ccr_inject_tool:
from headroom.proxy.helpers import apply_session_sticky_ccr_tool
tools, ccr_tool_injected = apply_session_sticky_ccr_tool(
provider="openai",
session_id=openai_session_id,
request_id=request_id,
existing_tools=tools,
has_compressed_content_this_turn=injector.has_compressed_content,
)
if ccr_tool_injected:
logger.debug(
f"[{request_id}] CCR: Injected retrieval tool for hashes: {injector.detected_hashes}"
)
else:
logger.debug(
f"[{request_id}] CCR: Tool already present (MCP?), skipped injection for hashes: {injector.detected_hashes}"
f"[{request_id}] CCR: tool registered (session={openai_session_id}, "
f"compressed_this_turn={injector.has_compressed_content}, "
f"hashes_seen={len(injector.detected_hashes)})"
)
if is_cache_mode(self.config.mode):

280
headroom/proxy/helpers.py
View file

@ -1591,6 +1591,286 @@ def apply_session_sticky_memory_tools(
return tools_out, added_bytes > 0
# ─── Session-sticky CCR tool injection (PR-B7) ─────────────────────────
#
# Per realignment plan PR-B7 (`REALIGNMENT/04-phase-B-live-zone.md`):
# once a session has performed any CCR compression, the
# `headroom_retrieve` tool stays registered in `body["tools"]` for every
# subsequent request in that session — never toggled off.
#
# The legacy `CCRToolInjector.has_compressed_content` flips on/off based
# on whether the *latest request* contained compression markers, which
# bust the prompt cache every time the flag flips. Sticky-on means the
# tool list bytes stay byte-stable across turns once injected.
class SessionCcrTracker:
"""Bounded LRU tracker recording per-(provider, session_id) CCR state.
Two pieces of state per session:
* ``has_done_ccr``: True once the proxy observed any CCR
compression marker in the messages of a request. Once True, it
never flips back to False (the prompt cache anchored on the
previous turn's tool list demands the tool stays present).
* ``golden_tool_bytes``: canonical serialization of the
``headroom_retrieve`` tool definition recorded the first time
the tracker injected it. Subsequent turns replay these bytes
verbatim.
Bounded by ``max_sessions`` via ``OrderedDict`` LRU. Mirrors
:class:`SessionToolTracker` semantics so the operator's mental model
is one tracker pattern, not two.
"""
def __init__(self, max_sessions: int | None = None) -> None:
if max_sessions is None:
max_sessions = get_tool_tracker_max_sessions()
if max_sessions <= 0:
raise ValueError("max_sessions must be > 0")
self._max_sessions = max_sessions
self._lock = threading.RLock()
# Value is (has_done_ccr, golden_tool_bytes_or_none).
self._sessions: OrderedDict[tuple[str, str], tuple[bool, bytes | None]] = OrderedDict()
@property
def active_sessions(self) -> int:
with self._lock:
return len(self._sessions)
def _key(self, provider: str, session_id: str) -> tuple[str, str]:
return (provider, session_id)
def has_done_ccr(self, provider: str, session_id: str) -> bool:
"""Return True iff this session has previously performed CCR."""
if not provider:
raise ValueError("provider must be non-empty")
if not session_id:
raise ValueError("session_id must be non-empty")
with self._lock:
entry = self._sessions.get(self._key(provider, session_id))
if entry is None:
return False
self._sessions.move_to_end(self._key(provider, session_id))
return entry[0]
def get_golden_tool_bytes(self, provider: str, session_id: str) -> bytes | None:
"""Return the recorded golden tool-definition bytes, or None."""
if not provider:
raise ValueError("provider must be non-empty")
if not session_id:
raise ValueError("session_id must be non-empty")
with self._lock:
entry = self._sessions.get(self._key(provider, session_id))
if entry is None:
return None
self._sessions.move_to_end(self._key(provider, session_id))
return entry[1]
def record_ccr_done(
self,
provider: str,
session_id: str,
golden_tool_bytes: bytes,
) -> None:
"""Mark the session as having performed CCR and pin the golden bytes.
First-write wins for ``golden_tool_bytes`` (subsequent calls
with the same session keep the original bytes — prevents drift
if the canonical serialization changed mid-session). The
``has_done_ccr`` flag is monotonic: once True, never False.
"""
if not provider:
raise ValueError("provider must be non-empty")
if not session_id:
raise ValueError("session_id must be non-empty")
if not golden_tool_bytes:
raise ValueError("golden_tool_bytes must be non-empty")
key = self._key(provider, session_id)
with self._lock:
existing = self._sessions.get(key)
if existing is None:
self._sessions[key] = (True, golden_tool_bytes)
else:
# Preserve original golden bytes; just promote the flag.
pinned = existing[1] if existing[1] is not None else golden_tool_bytes
self._sessions[key] = (True, pinned)
self._sessions.move_to_end(key)
while len(self._sessions) > self._max_sessions:
self._sessions.popitem(last=False)
def reset(self) -> None:
"""Clear all session state (test helper)."""
with self._lock:
self._sessions.clear()
# Process-wide singleton.
_session_ccr_tracker_lock = threading.Lock()
_session_ccr_tracker: SessionCcrTracker | None = None
def get_session_ccr_tracker() -> SessionCcrTracker:
"""Return the process-wide :class:`SessionCcrTracker` singleton."""
global _session_ccr_tracker
with _session_ccr_tracker_lock:
if _session_ccr_tracker is None:
_session_ccr_tracker = SessionCcrTracker()
return _session_ccr_tracker
def _reset_session_ccr_tracker_for_test() -> None:
"""Clear the process-wide CCR tracker (test-only)."""
global _session_ccr_tracker
with _session_ccr_tracker_lock:
_session_ccr_tracker = None
def apply_session_sticky_ccr_tool(
*,
provider: Literal["anthropic", "openai", "google"],
session_id: str | None,
request_id: str | None,
existing_tools: list[dict[str, Any]] | None,
has_compressed_content_this_turn: bool,
) -> tuple[list[dict[str, Any]], bool]:
"""Apply sticky-on CCR retrieval-tool injection per :class:`SessionCcrTracker`.
Coordination point for both Anthropic and OpenAI handlers — replaces
the legacy ``CCRToolInjector.inject_tool_definition`` "flip on, flip
off" behaviour.
Logic:
* If ``session_id`` is None: tracker is bypassed and the per-turn
``has_compressed_content_this_turn`` flag drives the decision
verbatim (matching legacy behaviour for WS / pre-session paths).
* If the session has previously done CCR (``has_done_ccr``):
ALWAYS inject the recorded golden bytes — even if this turn has
no fresh compression. That is the load-bearing PR-B7 fix.
* Otherwise, inject only when this turn produced compressed content.
The first injection records the golden bytes for future turns.
Tools whose name already equals ``CCR_TOOL_NAME`` (e.g. the client
pre-registered it via MCP) are not re-appended; the client's bytes
win.
Returns ``(updated_tools, was_injected)``. ``updated_tools`` is a
fresh list (caller-safe).
"""
from headroom.ccr.tool_injection import CCR_TOOL_NAME, create_ccr_tool_definition
if provider not in ("anthropic", "openai", "google"):
raise ValueError(f"unsupported provider: {provider!r}")
tools_out: list[dict[str, Any]] = list(existing_tools) if existing_tools else []
existing_names: set[str] = set()
for t in tools_out:
n = _extract_tool_name(t)
if n:
existing_names.add(n)
# Client (or MCP) already provided a tool by this name — don't double up.
if CCR_TOOL_NAME in existing_names:
log_tool_injection_decision(
provider=provider,
session_id=session_id,
decision="skip",
tool_definition_bytes_count=0,
request_id=request_id,
)
return tools_out, False
# No session_id (e.g. WS path): per-turn decision drives directly.
if not session_id:
if not has_compressed_content_this_turn:
log_tool_injection_decision(
provider=provider,
session_id=None,
decision="skip",
tool_definition_bytes_count=0,
request_id=request_id,
)
return tools_out, False
tool_def = create_ccr_tool_definition(provider)
canonical = serialize_tool_definition_canonical(tool_def)
tools_out.append(tool_def)
log_tool_injection_decision(
provider=provider,
session_id=None,
decision="inject_first_time",
tool_definition_bytes_count=len(canonical),
request_id=request_id,
)
return tools_out, True
tracker = get_session_ccr_tracker()
previously_done = tracker.has_done_ccr(provider, session_id)
if previously_done:
# Sticky replay path. Always inject — even if this turn had no
# fresh CCR compression. Prefer the recorded golden bytes; fall
# back to a freshly serialized definition if (somehow) the
# tracker lost them. Loud per build constraint #4: we log the
# path taken either way.
golden = tracker.get_golden_tool_bytes(provider, session_id)
if golden is not None:
try:
tool_def = json.loads(golden.decode("utf-8"))
except (UnicodeDecodeError, json.JSONDecodeError) as exc:
# Should never happen — golden bytes were produced by us.
raise RuntimeError(
f"corrupt golden CCR tool bytes for session {session_id}: {exc}"
) from exc
tools_out.append(tool_def)
log_tool_injection_decision(
provider=provider,
session_id=session_id,
decision="inject_sticky_replay",
tool_definition_bytes_count=len(golden),
request_id=request_id,
)
return tools_out, True
# Tracker says "done CCR" but somehow has no golden bytes. Pin
# them now so future turns are stable.
tool_def = create_ccr_tool_definition(provider)
canonical = serialize_tool_definition_canonical(tool_def)
tracker.record_ccr_done(provider, session_id, canonical)
tools_out.append(tool_def)
log_tool_injection_decision(
provider=provider,
session_id=session_id,
decision="inject_sticky_replay",
tool_definition_bytes_count=len(canonical),
request_id=request_id,
)
return tools_out, True
# Fresh session — only inject when this turn produced compressed content.
if not has_compressed_content_this_turn:
log_tool_injection_decision(
provider=provider,
session_id=session_id,
decision="skip",
tool_definition_bytes_count=0,
request_id=request_id,
)
return tools_out, False
tool_def = create_ccr_tool_definition(provider)
canonical = serialize_tool_definition_canonical(tool_def)
tracker.record_ccr_done(provider, session_id, canonical)
tools_out.append(tool_def)
log_tool_injection_decision(
provider=provider,
session_id=session_id,
decision="inject_first_time",
tool_definition_bytes_count=len(canonical),
request_id=request_id,
)
return tools_out, True
async def _read_request_body_bytes(request: Request) -> bytes:
"""Read and (if needed) decompress the request body, returning raw UTF-8 bytes.

385
tests/test_ccr_tool_always_on.py Normal file
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"""PR-B7 — `headroom_retrieve` tool always-on once a session has done CCR.
These tests pin three properties:
1. After a session has performed CCR even once, every subsequent
request in that session injects the tool — even when the current
request has no fresh compression markers.
2. A session that has NEVER done CCR does not get the tool injected.
3. The tool definition bytes are byte-stable across turns (snapshot
test). Any future change to the tool schema must update the
snapshot deliberately.
Tests target the canonical helper
`headroom.proxy.helpers.apply_session_sticky_ccr_tool` plus the
`SessionCcrTracker` semantics. The CCRToolInjector legacy path is
covered by `tests/test_ccr_tool_injection.py`.
"""
from __future__ import annotations
import pytest
from headroom.ccr.tool_injection import (
CCR_TOOL_NAME,
CCRToolInjector,
create_ccr_tool_definition,
)
from headroom.proxy.helpers import (
SessionCcrTracker,
_reset_session_ccr_tracker_for_test,
apply_session_sticky_ccr_tool,
get_session_ccr_tracker,
serialize_tool_definition_canonical,
)
@pytest.fixture(autouse=True)
def _reset_tracker():
_reset_session_ccr_tracker_for_test()
yield
_reset_session_ccr_tracker_for_test()
def _has_ccr_tool(tools: list[dict] | None) -> bool:
if not tools:
return False
for t in tools:
n = t.get("name") or t.get("function", {}).get("name")
if n == CCR_TOOL_NAME:
return True
return False
# ─── Sticky-on behavior ────────────────────────────────────────────────
def test_tool_registered_on_every_request_after_first_ccr():
"""Once a session has done CCR, the tool stays registered every turn."""
session_id = "sess-abc-123"
# Turn 1: this turn produced compressed content → first-time inject.
tools_1, injected_1 = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="req-1",
existing_tools=None,
has_compressed_content_this_turn=True,
)
assert injected_1 is True
assert _has_ccr_tool(tools_1)
# Turn 2: NO fresh compression this turn — but session has done CCR.
# Tool MUST still be injected (PR-B7 sticky-on).
tools_2, injected_2 = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="req-2",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected_2 is True, "sticky replay must inject even with no fresh CCR"
assert _has_ccr_tool(tools_2)
# Turn 3: still no fresh compression — sticky-on still fires.
tools_3, injected_3 = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="req-3",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected_3 is True
assert _has_ccr_tool(tools_3)
def test_tool_not_registered_if_session_never_did_ccr():
"""A session that never produced CCR markers gets no tool injection."""
session_id = "fresh-session-no-ccr"
tools, injected = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="req-1",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected is False
assert not _has_ccr_tool(tools)
# Tracker must NOT have recorded this session.
assert get_session_ccr_tracker().has_done_ccr("anthropic", session_id) is False
# Do it again — same outcome, no state leakage.
tools, injected = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="req-2",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected is False
assert not _has_ccr_tool(tools)
def test_independent_sessions_track_independently():
"""Two distinct session_ids do not bleed sticky state."""
sess_a = "sess-A"
sess_b = "sess-B"
# A does CCR; B does not.
apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=sess_a,
request_id="r1",
existing_tools=None,
has_compressed_content_this_turn=True,
)
# B's next turn (no fresh CCR) must NOT auto-inject.
tools_b, injected_b = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=sess_b,
request_id="r2",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected_b is False
assert not _has_ccr_tool(tools_b)
# A's next turn (no fresh CCR) MUST auto-inject (sticky).
tools_a, injected_a = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=sess_a,
request_id="r3",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected_a is True
assert _has_ccr_tool(tools_a)
def test_provider_isolation():
"""Same session_id under anthropic vs openai are tracked independently."""
session_id = "shared-session-id"
# Anthropic does CCR.
apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="r1",
existing_tools=None,
has_compressed_content_this_turn=True,
)
# OpenAI must NOT inherit anthropic's sticky state.
tools_o, injected_o = apply_session_sticky_ccr_tool(
provider="openai",
session_id=session_id,
request_id="r2",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected_o is False
assert not _has_ccr_tool(tools_o)
def test_existing_ccr_tool_in_client_list_skips_injection():
"""If client (e.g. via MCP) already provided headroom_retrieve, do not double up."""
session_id = "sess-with-mcp"
client_tool = {
"name": CCR_TOOL_NAME,
"description": "client-provided",
"input_schema": {"type": "object", "properties": {}, "required": []},
}
tools, injected = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="r1",
existing_tools=[client_tool],
has_compressed_content_this_turn=True,
)
assert injected is False
# Tool list still contains the client's version (not duplicated).
names = [t.get("name") for t in tools]
assert names.count(CCR_TOOL_NAME) == 1
def test_no_session_id_falls_back_to_per_turn_decision():
"""WS / pre-session paths with no session_id behave per-turn."""
# No fresh CCR + no session_id → no inject.
tools, injected = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=None,
request_id="r1",
existing_tools=None,
has_compressed_content_this_turn=False,
)
assert injected is False
# Fresh CCR + no session_id → inject (per-turn).
tools, injected = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=None,
request_id="r2",
existing_tools=None,
has_compressed_content_this_turn=True,
)
assert injected is True
assert _has_ccr_tool(tools)
# ─── Byte-stable tool definition ───────────────────────────────────────
# Snapshot of the canonical Anthropic CCR tool definition. Any change
# here MUST be deliberate — bumping the schema mid-session busts every
# active session's prompt cache (the tool list bytes are part of the
# cache key).
_ANTHROPIC_CCR_TOOL_SNAPSHOT_BYTES = (
b'{"name":"headroom_retrieve",'
b'"description":"Retrieve original uncompressed content that was '
b"compressed to save tokens. Use this when you need more data than "
b"what's shown in compressed tool results. The hash is provided in "
b'compression markers like [N items compressed... hash=abc123].",'
b'"input_schema":{"type":"object",'
b'"properties":{'
b'"hash":{"type":"string",'
b'"description":"Hash key from the compression marker '
b"(e.g., 'abc123' from hash=abc123)\"},"
b'"query":{"type":"string",'
b'"description":"Optional search query to filter results. '
b"If provided, only returns items matching the query. "
b'If omitted, returns all original items."}'
b"},"
b'"required":["hash"]}}'
)
_OPENAI_CCR_TOOL_SNAPSHOT_BYTES = (
b'{"type":"function",'
b'"function":{"name":"headroom_retrieve",'
b'"description":"Retrieve original uncompressed content that was '
b"compressed to save tokens. Use this when you need more data than "
b"what's shown in compressed tool results. The hash is provided in "
b'compression markers like [N items compressed... hash=abc123].",'
b'"parameters":{"type":"object",'
b'"properties":{'
b'"hash":{"type":"string",'
b'"description":"Hash key from the compression marker '
b"(e.g., 'abc123' from hash=abc123)\"},"
b'"query":{"type":"string",'
b'"description":"Optional search query to filter results. '
b"If provided, only returns items matching the query. "
b'If omitted, returns all original items."}'
b"},"
b'"required":["hash"]}}}'
)
def test_tool_definition_byte_stable():
"""Pin the canonical bytes of the Anthropic + OpenAI tool defs.
PR-B7 acceptance criterion: tool definition bytes are byte-stable.
Any future change to ``create_ccr_tool_definition`` must bump these
snapshots deliberately.
"""
anthropic_tool = create_ccr_tool_definition("anthropic")
canonical_anthropic = serialize_tool_definition_canonical(anthropic_tool)
assert canonical_anthropic == _ANTHROPIC_CCR_TOOL_SNAPSHOT_BYTES, (
f"Anthropic CCR tool definition bytes changed.\n"
f" expected: {_ANTHROPIC_CCR_TOOL_SNAPSHOT_BYTES!r}\n"
f" actual: {canonical_anthropic!r}\n"
f"If this change is intentional, update the snapshot in this "
f"test and ensure the prompt-cache implications are reviewed."
)
openai_tool = create_ccr_tool_definition("openai")
canonical_openai = serialize_tool_definition_canonical(openai_tool)
assert canonical_openai == _OPENAI_CCR_TOOL_SNAPSHOT_BYTES, (
f"OpenAI CCR tool definition bytes changed.\n"
f" expected: {_OPENAI_CCR_TOOL_SNAPSHOT_BYTES!r}\n"
f" actual: {canonical_openai!r}"
)
def test_sticky_replay_returns_byte_equal_tool_each_turn():
"""The bytes injected on turn 2 must equal the bytes injected on turn 1."""
session_id = "sess-byte-stable"
tools_1, _ = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="r1",
existing_tools=None,
has_compressed_content_this_turn=True,
)
tools_2, _ = apply_session_sticky_ccr_tool(
provider="anthropic",
session_id=session_id,
request_id="r2",
existing_tools=None,
has_compressed_content_this_turn=False,
)
# Both tools lists should contain exactly one CCR tool with the
# same canonical bytes.
ccr_1 = next(t for t in tools_1 if t.get("name") == CCR_TOOL_NAME)
ccr_2 = next(t for t in tools_2 if t.get("name") == CCR_TOOL_NAME)
assert serialize_tool_definition_canonical(ccr_1) == serialize_tool_definition_canonical(ccr_2)
# ─── SessionCcrTracker unit coverage ────────────────────────────────────
def test_session_ccr_tracker_monotonic_has_done_ccr():
"""``has_done_ccr`` is monotonic — never flips back to False."""
tracker = SessionCcrTracker(max_sessions=10)
assert tracker.has_done_ccr("anthropic", "s1") is False
golden = serialize_tool_definition_canonical(create_ccr_tool_definition("anthropic"))
tracker.record_ccr_done("anthropic", "s1", golden)
assert tracker.has_done_ccr("anthropic", "s1") is True
# Re-record with a different golden_bytes — original bytes win
# (first-write wins) and flag stays True.
new_golden = b'{"name":"different","input_schema":{}}'
tracker.record_ccr_done("anthropic", "s1", new_golden)
assert tracker.has_done_ccr("anthropic", "s1") is True
assert tracker.get_golden_tool_bytes("anthropic", "s1") == golden
def test_session_ccr_tracker_lru_bound():
"""Tracker evicts oldest sessions once `max_sessions` is exceeded."""
tracker = SessionCcrTracker(max_sessions=3)
golden = b"{}"
for i in range(5):
tracker.record_ccr_done("anthropic", f"s{i}", golden)
# Only 3 most recent should remain.
assert tracker.active_sessions == 3
assert tracker.has_done_ccr("anthropic", "s0") is False
assert tracker.has_done_ccr("anthropic", "s1") is False
assert tracker.has_done_ccr("anthropic", "s4") is True
def test_session_ccr_tracker_reset_clears_state():
tracker = SessionCcrTracker(max_sessions=10)
tracker.record_ccr_done("anthropic", "s1", b"{}")
assert tracker.active_sessions == 1
tracker.reset()
assert tracker.active_sessions == 0
assert tracker.has_done_ccr("anthropic", "s1") is False
# ─── Per-request injector legacy path (PR-B7 backwards compat) ─────────
def test_ccrtoolinjector_session_has_done_ccr_kwarg():
"""``CCRToolInjector.inject_tool_definition`` accepts session_has_done_ccr."""
injector = CCRToolInjector(provider="anthropic", inject_tool=True)
# No fresh markers, no sticky flag → no inject (legacy behaviour).
tools, was = injector.inject_tool_definition(None)
assert was is False
assert tools == []
# No fresh markers, sticky flag set → inject (PR-B7 path).
tools, was = injector.inject_tool_definition(None, session_has_done_ccr=True)
assert was is True
assert _has_ccr_tool(tools)