passenger-datadog-monitor

Polls passenger-status --show=xml every 10 seconds and emits Passenger health metrics to Datadog via StatsD.

Forked from Sjeanpierre/passenger-datadog-monitor.

Metrics

Aggregated (passenger.*): request queue depth, pool usage, process uptime (min/avg/max gauges), total memory (gauge), memory distribution (histogram), total processed requests (count delta).

Per-process (passenger.process.*, tagged by pid): memory (histogram), thread count (gauge), idle time (gauge), requests processed (count delta).

Usage in Dockerfile

COPY --from=ghcr.io/ibotta/passenger-datadog-monitor:v<version> \
  /usr/local/bin/passenger-datadog-monitor /usr/local/bin/passenger-datadog-monitor

The binary runs as a daemon and sends metrics to the local StatsD agent:

passenger-datadog-monitor -host=$STATSD_HOST -port=$STATSD_PORT

Flags

Flag	Default	Description
-host	127.0.0.1	StatsD host
-port	8125	StatsD UDP port
-print	false	Print metrics to stdout for debugging
-tags	(none)	Tags for all metrics — comma-separated, space-separated, or mixed (e.g. source:api,service:my-service or source:api service:my-service)

supervisord example

Space-separated tags (DD_TAGS) can be passed directly using supervisord's %(ENV_...)s interpolation:

[program:passenger-datadog-monitor]
command=/usr/local/bin/passenger-datadog-monitor -host=%(ENV_STATSD_ENDPOINT_IP)s -port=%(ENV_STATSD_ENDPOINT_PORT)s -tags="version:%(ENV_DD_VERSION)s service:%(ENV_DD_SERVICE)s env:%(ENV_DD_ENV)s %(ENV_DD_TAGS)s"

Development

make build    # compile binary to bin/
make test     # run tests with race detector
make lint     # run golangci-lint
make docker   # build Docker image locally