prometheus-rs

# Configuration This server can be configured via environment variables and a few CLI flags. CLI flags take precedence over environment variables for the same setting. ::: tip Precedence CLI flag > environment variable > built-in default ::: ## Quick reference | Name | Type | Default | CLI flag | Description | |-------------------------------|-------------------|-------------------------|-------------------------|-------------------------------------------------------------------------------| | `PROMETHEUS_URL` | string (URL) | `http://localhost:9090` | `--prometheus-url` | Base URL of your Prometheus server | | `PROMETHEUS_TIMEOUT` | integer (seconds) | `10` | — | HTTP request timeout | | `PROMETHEUS_RETRIES` | integer | `3` | — | Number of retries for Prometheus API calls | | `PROMETHEUS_RETRY_BACKOFF_MS` | integer (ms) | `500` | — | Time to wait between retries | | `PROMETHEUS_MIN_INTERVAL_MS` | integer (ms) | none | — | If set, enforces a minimum interval between query requests (basic rate limit) | | `PROMETHEUS_CACHE_TTL_SECS` | integer (seconds) | none | — | TTL for simple in-process caches (list metrics and label values) | | `PROMETHEUS_USERNAME` | string | none | `--prometheus-username` | Basic auth username | | `PROMETHEUS_PASSWORD` | string | none | `--prometheus-password` | Basic auth password | | — | boolean | `false` | `--mcp` | Start MCP server over stdio | | — | boolean | `false` | `--metrics-exporter` | Enable internal Prometheus metrics at `/metrics` | | — | integer (port) | `9091` | `--metrics-port` | Port to expose the internal `/metrics` endpoint when enabled | ::: note Advanced HTTP behavior (timeout, retries, backoff, rate limiting) is environment-only. Caches are per-process and reset on restart. ::: ## Basic Authentication You can configure Basic Auth using either environment variables or CLI flags. ::: code-group ```bash [env vars] export PROMETHEUS_URL=https://prom.example.com export PROMETHEUS_USERNAME=api export PROMETHEUS_PASSWORD=secret prometheus-mcp --mcp ``` ```bash [CLI flags] prometheus-mcp --mcp \ --prometheus-url https://prom.example.com \ --prometheus-username api \ --prometheus-password secret ``` ```bash [Docker] docker run --rm -it \ -e PROMETHEUS_URL=https://prom.example.com \ -e PROMETHEUS_USERNAME=api \ -e PROMETHEUS_PASSWORD=secret \ prometheus-mcp:latest --mcp ``` ::: ::: warning Security Avoid committing secrets. Prefer environment variables, Docker secrets, or a host secret manager. ::: ## Metrics Exporter If enabled with `--metrics-exporter`, the binary exposes its own Prometheus metrics at `/metrics` on `--metrics-port` ( default 9091). ```bash prometheus-mcp --mcp --metrics-exporter --metrics-port 9091 curl -s http://localhost:9091/metrics | head ```