rob thijssen
67b9b044d3
Emit cortex_requests_total, cortex_request_duration_seconds, cortex_request_errors_total, and cortex_cold_starts_total with model and node labels on every proxied request. Add install_test_recorder() for testing metrics without HTTP listener. Integration test verifies counters and histograms appear after proxy. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
59 lines
2.0 KiB
Rust
59 lines
2.0 KiB
Rust
//! Prometheus metrics exporter.
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//!
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//! Runs on a separate port from the main API, exposing `/metrics`
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//! in Prometheus text format.
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use anyhow::Result;
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use metrics_exporter_prometheus::PrometheusBuilder;
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use std::net::SocketAddr;
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/// Install the Prometheus metrics recorder and return a handle.
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/// The `/metrics` endpoint is served by the exporter's built-in HTTP server.
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pub fn install(listen: &str) -> Result<()> {
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let addr: SocketAddr = listen.parse()?;
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PrometheusBuilder::new()
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.with_http_listener(addr)
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.install()
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.map_err(|e| anyhow::anyhow!("failed to install Prometheus exporter: {e}"))?;
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tracing::info!("prometheus metrics exporter on {addr}");
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describe_metrics();
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Ok(())
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}
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/// Install a recorder for testing (no HTTP listener). Returns a handle
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/// that can render the current metrics as Prometheus text.
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pub fn install_test_recorder() -> Result<metrics_exporter_prometheus::PrometheusHandle> {
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let handle = PrometheusBuilder::new()
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.install_recorder()
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.map_err(|e| anyhow::anyhow!("failed to install test recorder: {e}"))?;
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describe_metrics();
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Ok(handle)
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}
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fn describe_metrics() {
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metrics::describe_histogram!(
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"cortex_request_duration_seconds",
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"Total request latency in seconds"
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);
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metrics::describe_histogram!(
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"cortex_time_to_first_token_seconds",
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"Time to first token in seconds"
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);
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metrics::describe_histogram!(
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"cortex_tokens_per_second",
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"Generation throughput in tokens per second"
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);
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metrics::describe_counter!("cortex_requests_total", "Total number of proxied requests");
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metrics::describe_counter!(
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"cortex_request_errors_total",
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"Total number of failed proxy requests"
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);
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metrics::describe_counter!("cortex_evictions_total", "Total number of model evictions");
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metrics::describe_counter!(
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"cortex_cold_starts_total",
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"Total number of cold-start model loads"
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);
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}
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