headroom/tests/test_proxy_cache_ttl_metrics.py

"""Tests for observed Anthropic cache TTL bucket metrics."""

from __future__ import annotations

import asyncio

import pytest

from headroom.observability import reset_headroom_tracing, reset_otel_metrics
from headroom.proxy.cost import CostTracker, build_prefix_cache_stats
from headroom.proxy.prometheus_metrics import PrometheusMetrics
from headroom.proxy.savings_tracker import SavingsTracker


def test_prometheus_metrics_tracks_observed_ttl_buckets() -> None:
    metrics = PrometheusMetrics()

    asyncio.run(
        metrics.record_request(
            provider="anthropic",
            model="claude-opus-4-6",
            input_tokens=100,
            output_tokens=20,
            tokens_saved=5,
            latency_ms=10.0,
            cache_read_tokens=40,
            cache_write_tokens=60,
            cache_write_5m_tokens=10,
            cache_write_1h_tokens=50,
        )
    )

    stats = metrics.cache_by_provider["anthropic"]
    assert stats["cache_write_5m_tokens"] == 10
    assert stats["cache_write_1h_tokens"] == 50
    assert stats["cache_write_5m_requests"] == 1
    assert stats["cache_write_1h_requests"] == 1


def test_cost_tracker_exposes_observed_ttl_buckets_per_model() -> None:
    tracker = CostTracker()
    tracker.record_tokens(
        "claude-opus-4-6",
        tokens_saved=10,
        tokens_sent=90,
        cache_read_tokens=40,
        cache_write_tokens=60,
        cache_write_5m_tokens=10,
        cache_write_1h_tokens=50,
        uncached_tokens=20,
    )

    stats = tracker.stats()
    assert stats["cache_write_5m_tokens"] == 10
    assert stats["cache_write_1h_tokens"] == 50
    assert stats["per_model"]["claude-opus-4-6"]["cache_write_5m_tokens"] == 10
    assert stats["per_model"]["claude-opus-4-6"]["cache_write_1h_tokens"] == 50


def test_prefix_cache_stats_include_observed_ttl_mix() -> None:
    metrics = PrometheusMetrics()
    provider_stats = metrics.cache_by_provider["anthropic"]
    provider_stats["requests"] = 2
    provider_stats["hit_requests"] = 1
    provider_stats["cache_read_tokens"] = 40
    provider_stats["cache_write_tokens"] = 60
    provider_stats["cache_write_5m_tokens"] = 15
    provider_stats["cache_write_1h_tokens"] = 45
    provider_stats["cache_write_5m_requests"] = 1
    provider_stats["cache_write_1h_requests"] = 1

    stats = build_prefix_cache_stats(metrics, None)
    anthropic = stats["by_provider"]["anthropic"]

    assert anthropic["observed_ttl_buckets"]["5m"]["tokens"] == 15
    assert anthropic["observed_ttl_buckets"]["1h"]["tokens"] == 45
    assert anthropic["observed_ttl_mix"]["5m_pct"] == 25.0
    assert anthropic["observed_ttl_mix"]["1h_pct"] == 75.0
    assert stats["totals"]["observed_ttl_buckets"]["5m"]["tokens"] == 15
    assert stats["totals"]["observed_ttl_buckets"]["1h"]["tokens"] == 45


def test_prefix_cache_stats_subtracts_write_premium_from_provider_net_savings(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    metrics = PrometheusMetrics()
    metrics.cache_by_provider["anthropic"].update(
        {
            "requests": 2,
            "hit_requests": 1,
            "cache_read_tokens": 40,
            "cache_write_tokens": 60,
            "cache_write_5m_tokens": 60,
            "cache_write_1h_tokens": 0,
            "cache_write_5m_requests": 1,
            "cache_write_1h_requests": 0,
        }
    )

    tracker = CostTracker()
    tracker._tokens_sent_by_model.update({"claude-opus-4-6": 1})
    monkeypatch.setattr(CostTracker, "_get_list_price", lambda _self, _model: 100.0)

    stats = build_prefix_cache_stats(metrics, tracker)

    anthropic = stats["by_provider"]["anthropic"]

    assert anthropic["savings_usd"] == 0.0036
    assert anthropic["write_premium_usd"] == 0.0015
    assert anthropic["net_savings_usd"] == 0.0021


def test_prefix_cache_stats_prices_by_most_used_model(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """Cache-read savings must be valued with the highest-volume model's price,
    not whichever model was recorded first. A Claude Code session sends Haiku
    (titles) and Sonnet (main loop); pricing the savings at Haiku's rate because
    it was inserted first understates the dashboard figure ~3.75x."""
    prices = {"claude-haiku-4-5": 0.80, "claude-sonnet-4-5": 3.00}
    monkeypatch.setattr(CostTracker, "_get_list_price", lambda _self, m: prices.get(m))

    def _savings(tokens_by_model: dict[str, int]) -> float:
        metrics = PrometheusMetrics()
        # Use a large read count so the reported savings_usd (rounded to 4 dp)
        # stays exact and the price ratio is not lost to rounding.
        metrics.cache_by_provider["anthropic"].update(
            {
                "requests": 1,
                "hit_requests": 1,
                "cache_read_tokens": 1_000_000,
                "cache_write_tokens": 0,
                "cache_write_5m_tokens": 0,
                "cache_write_1h_tokens": 0,
                "cache_write_5m_requests": 0,
                "cache_write_1h_requests": 0,
            }
        )
        tracker = CostTracker()
        tracker._tokens_sent_by_model.update(tokens_by_model)
        stats = build_prefix_cache_stats(metrics, tracker)
        return stats["by_provider"]["anthropic"]["savings_usd"]

    # Haiku recorded first, but Sonnet carries the higher token volume.
    haiku_first = _savings({"claude-haiku-4-5": 500, "claude-sonnet-4-5": 50_000})
    sonnet_only = _savings({"claude-sonnet-4-5": 50_000})
    haiku_only = _savings({"claude-haiku-4-5": 500})

    # Priced by Sonnet regardless of insertion order, not by first-seen Haiku.
    assert haiku_first == sonnet_only
    assert haiku_first > haiku_only
    assert haiku_only == pytest.approx(sonnet_only * 0.80 / 3.00)


def test_prefix_cache_stats_subtracts_write_premium_from_total_net_savings(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    metrics = PrometheusMetrics()
    metrics.cache_by_provider["anthropic"].update(
        {
            "requests": 2,
            "hit_requests": 1,
            "cache_read_tokens": 40,
            "cache_write_tokens": 60,
            "cache_write_5m_tokens": 60,
            "cache_write_1h_tokens": 0,
            "cache_write_5m_requests": 1,
            "cache_write_1h_requests": 0,
        }
    )
    metrics.cache_by_provider["openai"].update(
        {
            "requests": 1,
            "hit_requests": 1,
            "cache_read_tokens": 20,
            "cache_write_tokens": 10,
            "cache_write_5m_tokens": 0,
            "cache_write_1h_tokens": 10,
            "cache_write_5m_requests": 0,
            "cache_write_1h_requests": 1,
        }
    )

    tracker = CostTracker()
    tracker._tokens_sent_by_model.update({"claude-opus-4-6": 1, "gpt-4o": 1})
    monkeypatch.setattr(CostTracker, "_get_list_price", lambda _self, _model: 100.0)

    stats = build_prefix_cache_stats(metrics, tracker)

    openai = stats["by_provider"]["openai"]

    assert openai["write_premium_usd"] == 0.0
    assert openai["net_savings_usd"] == openai["savings_usd"]
    assert stats["totals"]["savings_usd"] == 0.0046
    assert stats["totals"]["write_premium_usd"] == 0.0015
    assert stats["totals"]["net_savings_usd"] == 0.0031


def test_prefix_cache_stats_keeps_net_equal_without_write_premium(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    metrics = PrometheusMetrics()
    metrics.cache_by_provider["openai"].update(
        {
            "requests": 1,
            "hit_requests": 1,
            "cache_read_tokens": 20,
            "cache_write_tokens": 0,
            "cache_write_5m_tokens": 0,
            "cache_write_1h_tokens": 0,
            "cache_write_5m_requests": 0,
            "cache_write_1h_requests": 0,
        }
    )

    tracker = CostTracker()
    tracker._tokens_sent_by_model.update({"gpt-4o": 1})
    monkeypatch.setattr(CostTracker, "_get_list_price", lambda _self, _model: 100.0)

    stats = build_prefix_cache_stats(metrics, tracker)

    openai = stats["by_provider"]["openai"]

    assert openai["savings_usd"] == 0.001
    assert openai["write_premium_usd"] == 0.0
    assert openai["net_savings_usd"] == openai["savings_usd"]


def test_prometheus_metrics_export_includes_extended_fields(tmp_path) -> None:
    metrics = PrometheusMetrics(
        savings_tracker=SavingsTracker(path=str(tmp_path / "proxy_savings.json"))
    )

    asyncio.run(
        metrics.record_request(
            provider="anthropic",
            model="claude-opus-4-6",
            input_tokens=100,
            output_tokens=20,
            tokens_saved=5,
            latency_ms=12.5,
            overhead_ms=3.0,
            ttfb_ms=9.0,
            pipeline_timing={"router": 4.5},
            waste_signals={"json_bloat": 7},
            cache_read_tokens=40,
            cache_write_tokens=60,
            cache_write_5m_tokens=10,
            cache_write_1h_tokens=50,
            uncached_input_tokens=20,
        )
    )
    asyncio.run(metrics.record_cache_bust(11))

    exported = asyncio.run(metrics.export())

    assert "headroom_requests_total 1" in exported
    assert "headroom_tokens_saved_total 5" in exported
    assert "headroom_persistent_savings_requests_total 1" in exported
    assert "headroom_persistent_savings_tokens_saved_total 5" in exported
    assert "headroom_persistent_savings_input_tokens_total 100" in exported
    assert "headroom_latency_ms_count 1" in exported
    assert 'headroom_transform_timing_ms_sum{transform="router"} 4.5' in exported
    assert 'headroom_waste_signal_tokens_total{signal="json_bloat"} 7' in exported
    assert 'headroom_cache_write_ttl_tokens_total{provider="anthropic",ttl="5m"} 10' in exported
    assert 'headroom_provider_cache_hit_requests_total{provider="anthropic"} 1' in exported
    assert "headroom_cache_bust_tokens_lost_total 11" in exported


def test_prometheus_export_includes_persistent_savings_after_restart(tmp_path) -> None:
    savings_path = tmp_path / "proxy_savings.json"
    metrics = PrometheusMetrics(savings_tracker=SavingsTracker(path=str(savings_path)))

    asyncio.run(
        metrics.record_request(
            provider="openai",
            model="gpt-4o",
            input_tokens=120,
            output_tokens=20,
            tokens_saved=40,
            latency_ms=12.5,
        )
    )

    reloaded = PrometheusMetrics(savings_tracker=SavingsTracker(path=str(savings_path)))
    exported = asyncio.run(reloaded.export())

    assert "headroom_tokens_saved_total 0" in exported
    assert "headroom_requests_total 0" in exported
    assert "headroom_persistent_savings_requests_total 1" in exported
    assert "headroom_persistent_savings_tokens_saved_total 40" in exported
    assert "headroom_persistent_savings_input_tokens_total 120" in exported


def test_streaming_parser_extracts_anthropic_ttl_bucket_usage() -> None:
    from headroom.proxy.server import HeadroomProxy, ProxyConfig

    proxy = HeadroomProxy(
        ProxyConfig(
            optimize=False,
            cache_enabled=False,
            rate_limit_enabled=False,
            cost_tracking_enabled=False,
            log_requests=False,
            ccr_inject_tool=False,
            ccr_handle_responses=False,
            ccr_context_tracking=False,
        )
    )

    chunk = (
        b'data: {"type":"message_start","message":{"usage":{"input_tokens":12,'
        b'"cache_read_input_tokens":3,"cache_creation_input_tokens":9,'
        b'"cache_creation":{"ephemeral_5m_input_tokens":4,"ephemeral_1h_input_tokens":5}}}}\n\n'
    )
    usage = proxy._parse_sse_usage(chunk, "anthropic")

    assert usage is not None
    assert usage["cache_creation_ephemeral_5m_input_tokens"] == 4
    assert usage["cache_creation_ephemeral_1h_input_tokens"] == 5


def test_stats_endpoint_reports_observed_ttl_buckets() -> None:
    pytest.importorskip("fastapi")
    from fastapi.testclient import TestClient

    from headroom.proxy.server import ProxyConfig, create_app

    app = create_app(
        ProxyConfig(
            optimize=False,
            cache_enabled=False,
            rate_limit_enabled=False,
            cost_tracking_enabled=False,
            log_requests=False,
            ccr_inject_tool=False,
            ccr_handle_responses=False,
            ccr_context_tracking=False,
        )
    )

    proxy = app.state.proxy
    provider_stats = proxy.metrics.cache_by_provider["anthropic"]
    provider_stats["requests"] = 1
    provider_stats["hit_requests"] = 1
    provider_stats["cache_read_tokens"] = 30
    provider_stats["cache_write_tokens"] = 70
    provider_stats["cache_write_5m_tokens"] = 20
    provider_stats["cache_write_1h_tokens"] = 50
    provider_stats["cache_write_5m_requests"] = 1
    provider_stats["cache_write_1h_requests"] = 1

    with TestClient(app) as client:
        response = client.get("/stats")

    assert response.status_code == 200
    prefix_cache = response.json()["prefix_cache"]
    anthropic = prefix_cache["by_provider"]["anthropic"]
    assert anthropic["observed_ttl_buckets"]["5m"]["tokens"] == 20
    assert anthropic["observed_ttl_buckets"]["1h"]["tokens"] == 50
    assert prefix_cache["totals"]["observed_ttl_mix"]["active_buckets"] == ["5m", "1h"]


def test_stats_endpoint_reports_otel_configuration(monkeypatch: pytest.MonkeyPatch) -> None:
    pytest.importorskip("fastapi")
    from fastapi.testclient import TestClient

    from headroom.proxy.server import ProxyConfig, create_app

    reset_otel_metrics()
    monkeypatch.setenv("HEADROOM_OTEL_METRICS_ENABLED", "1")
    monkeypatch.setenv("HEADROOM_OTEL_METRICS_EXPORTER", "console")

    app = create_app(
        ProxyConfig(
            optimize=False,
            cache_enabled=False,
            rate_limit_enabled=False,
            cost_tracking_enabled=False,
            log_requests=False,
            ccr_inject_tool=False,
            ccr_handle_responses=False,
            ccr_context_tracking=False,
        )
    )

    with TestClient(app) as client:
        response = client.get("/stats")

    assert response.status_code == 200
    otel = response.json()["otel"]
    assert otel["configured"] is True
    assert otel["enabled"] is True
    assert otel["service_name"] == "headroom-proxy"
    assert otel["exporter"] == "console"


def test_stats_endpoint_reports_langfuse_configuration(monkeypatch: pytest.MonkeyPatch) -> None:
    pytest.importorskip("fastapi")
    from fastapi.testclient import TestClient

    from headroom.proxy.server import ProxyConfig, create_app

    reset_headroom_tracing()
    monkeypatch.setenv("HEADROOM_LANGFUSE_ENABLED", "1")
    monkeypatch.setenv("LANGFUSE_PUBLIC_KEY", "pk-lf-test")
    monkeypatch.setenv("LANGFUSE_SECRET_KEY", "sk-lf-test")
    monkeypatch.setenv("LANGFUSE_BASE_URL", "https://cloud.langfuse.com")

    app = create_app(
        ProxyConfig(
            optimize=False,
            cache_enabled=False,
            rate_limit_enabled=False,
            cost_tracking_enabled=False,
            log_requests=False,
            ccr_inject_tool=False,
            ccr_handle_responses=False,
            ccr_context_tracking=False,
        )
    )

    with TestClient(app) as client:
        response = client.get("/stats")

    assert response.status_code == 200
    langfuse = response.json()["langfuse"]
    assert langfuse["configured"] is True
    assert langfuse["enabled"] is True
    assert langfuse["service_name"] == "headroom-proxy"
    assert langfuse["endpoint"] == "https://cloud.langfuse.com/api/public/otel/v1/traces"


# --- Cache-miss attribution (#1313) ---


def test_record_cache_miss_attribution_buckets_by_provider_and_reason() -> None:
    metrics = PrometheusMetrics()
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "ttl_expiry"))
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "ttl_expiry"))
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "prefix_change"))
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "unknown"))

    buckets = metrics.cache_miss_attribution_by_provider["anthropic"]
    assert buckets["ttl_expiry"] == 2
    assert buckets["prefix_change"] == 1
    assert buckets["unknown"] == 1


def test_prefix_cache_stats_include_miss_attribution() -> None:
    metrics = PrometheusMetrics()
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "ttl_expiry"))
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "ttl_expiry"))
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "prefix_change"))
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "unknown"))

    stats = build_prefix_cache_stats(metrics, None)
    ma = stats["miss_attribution"]

    assert ma["totals"]["ttl_expiry"] == 2
    assert ma["totals"]["prefix_change"] == 1
    assert ma["totals"]["unknown"] == 1
    assert ma["totals"]["total"] == 4
    # Percentages are over attributed (non-unknown) misses: 2 / 3, 1 / 3.
    assert ma["totals"]["ttl_expiry_pct"] == 66.7
    assert ma["totals"]["prefix_change_pct"] == 33.3
    assert ma["by_provider"]["anthropic"]["total"] == 4


def test_prefix_cache_stats_miss_attribution_empty_when_no_misses() -> None:
    metrics = PrometheusMetrics()
    stats = build_prefix_cache_stats(metrics, None)
    ma = stats["miss_attribution"]
    assert ma["totals"]["total"] == 0
    assert ma["totals"]["ttl_expiry_pct"] == 0.0
    assert ma["by_provider"] == {}


def test_prometheus_export_includes_miss_attribution() -> None:
    metrics = PrometheusMetrics()
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "ttl_expiry"))
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "prefix_change"))

    exported = asyncio.run(metrics.export())

    assert (
        'headroom_cache_miss_attribution_total{provider="anthropic",reason="ttl_expiry"} 1'
        in exported
    )
    assert (
        'headroom_cache_miss_attribution_total{provider="anthropic",reason="prefix_change"} 1'
        in exported
    )


def test_reset_runtime_clears_miss_attribution() -> None:
    metrics = PrometheusMetrics()
    asyncio.run(metrics.record_cache_miss_attribution("anthropic", "ttl_expiry"))
    asyncio.run(metrics.reset_runtime())
    assert dict(metrics.cache_miss_attribution_by_provider) == {}