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ReverseDock

Metrics

ReverseDock since v0.1 exports Prometheus metrics in the text format at GET /metrics on the admin listener (127.0.0.1:2080 unless admin.listener says otherwise). The endpoint needs no token. Set observability.metrics.prometheus: false to turn it off; it then answers 404.

Terminal window
curl -s http://127.0.0.1:2080/metrics

Label values come from your configuration (listener, route, service and certificate names) or from small fixed sets, never from request data such as paths or hosts, so the number of series stays bounded.

HTTP

Section titled “HTTP”

rdock_http_requests_total

Section titled “rdock_http_requests_total”

Counter. HTTP requests handled, counted when the response is finished.

Label Values
listener Listener name.
route Route name; empty when no route matched or the request was refused before routing.
service Service of the route; empty when there is no route.
method GET, HEAD, POST, PUT, DELETE, PATCH, OPTIONS, CONNECT, TRACE, or OTHER for any other method.
status_class 1xx, 2xx, 3xx, 4xx or 5xx. A request whose client went away before any response was sent counts as 5xx.

rdock_http_request_duration_seconds

Section titled “rdock_http_request_duration_seconds”

Histogram. Time from the request headers to the end of the response, in seconds.

Label Values
listener Listener name.
route Route name, or empty.

Buckets: 0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10, 30 seconds.

rdock_upstream_errors_total

Section titled “rdock_upstream_errors_total”

Counter. Failed attempts to connect to a backend.

Label Values
service Service name.
kind connect (refused or failed) or timeout (longer than the service’s timeouts.connect).

Errors after the connection is open, such as a read timeout, show up as 502 or 504 in rdock_http_requests_total and in the access log.

Connections and TLS

Section titled “Connections and TLS”

rdock_connections_open

Section titled “rdock_connections_open”

Gauge. Client connections open now. Label: listener.

rdock_connections_total

Section titled “rdock_connections_total”

Counter. Client connections accepted. Label: listener.

rdock_tls_handshake_errors_total

Section titled “rdock_tls_handshake_errors_total”

Counter. TLS handshakes that failed or did not finish within the listener’s timeouts.request_header. Label: listener.

rdock_cert_expiry_timestamp_seconds

Section titled “rdock_cert_expiry_timestamp_seconds”

Gauge. Expiry (notAfter) of each certificate in certificates, in seconds since the Unix epoch. Label: name, the key under certificates. Updated whenever a configuration is applied, including when certificate files change.

Configuration

Section titled “Configuration”

rdock_config_generation

Section titled “rdock_config_generation”

Gauge. Generation number of the configuration in use. It starts at 1 and grows with each applied reload.

rdock_config_reloads_total

Section titled “rdock_config_reloads_total”

Counter. Attempts to apply a configuration, including the first one at start. Label: result, which is applied or rejected. A rejected reload leaves the running configuration in place.

Build

Section titled “Build”

rdock_build_info

Section titled “rdock_build_info”

Gauge, always 1. Labels: version (for example 0.3.0-alpha.1) and commit.

When series appear

Section titled “When series appear”

Counters and gauges with labels appear after their first event: rdock_tls_handshake_errors_total is missing until a handshake fails, and rdock_cert_expiry_timestamp_seconds until a certificate is loaded. Use or vector(0) in queries that must always return a value.

Example queries

Section titled “Example queries”
# Requests per second by route
sum by (route) (rate(rdock_http_requests_total[5m]))


# Share of 5xx answers per service
sum by (service) (rate(rdock_http_requests_total{status_class="5xx"}[5m]))
  / sum by (service) (rate(rdock_http_requests_total[5m]))


# 95th percentile latency per route
histogram_quantile(0.95, sum by (le, route) (rate(rdock_http_request_duration_seconds_bucket[5m])))


# Days until each certificate expires
(rdock_cert_expiry_timestamp_seconds - time()) / 86400


# Reloads that failed in the last hour
increase(rdock_config_reloads_total{result="rejected"}[1h]) > 0
Section titled “Related”