Logs and metrics

ddup writes logs to the standard output, and can export logs and metrics with OpenTelemetry or expose metrics for Prometheus.

Logs#

Set the level and format in the configuration:

logs:
  # debug, info, warn, or error
  level: info
  # Write one JSON object per line instead of text
  json: false

At the info level, ddup logs every change to DNS and every failed check.
At the debug level, ddup also logs every successful check, and every check that didn’t need a DNS update.

Exporting with OpenTelemetry#

ddup can send logs and metrics to an OpenTelemetry collector, or to any backend that accepts OTLP, such as Grafana, Honeycomb, or Datadog. Exporting is off by default: turn it on with environment variables.

# Export metrics
export OTEL_METRICS_EXPORTER=otlp
# Export logs too, in addition to writing them to the standard output
export OTEL_LOGS_EXPORTER=otlp
# Where to send them
export OTEL_EXPORTER_OTLP_ENDPOINT=http://otel-collector:4318

For example, with Docker:

docker run -d \
  --name ddup \
  --read-only \
  -v $HOME/.ddup:/etc/ddup:ro \
  -e OTEL_METRICS_EXPORTER=otlp \
  -e OTEL_LOGS_EXPORTER=otlp \
  -e OTEL_EXPORTER_OTLP_ENDPOINT=http://otel-collector:4318 \
  ghcr.io/italypaleale/ddup:v0

Variable	Description	Default
`OTEL_METRICS_EXPORTER`	`otlp` to export metrics, `prometheus` to expose them for Prometheus, or `console` to print them	`none`
`OTEL_LOGS_EXPORTER`	`otlp` to export logs, or `console` to print them	`none`
`OTEL_EXPORTER_OTLP_ENDPOINT`	Address of the OTLP collector	`http://localhost:4318`
`OTEL_EXPORTER_OTLP_PROTOCOL`	`http/protobuf` or `grpc`	`http/protobuf`
`OTEL_EXPORTER_OTLP_HEADERS`	Headers to send to the collector, such as API keys, as `key1=value1,key2=value2`
`OTEL_RESOURCE_ATTRIBUTES`	Attributes added to all logs and metrics, as `key1=value1,key2=value2`

Logs and metrics are reported with the service name ddup. See the OpenTelemetry documentation for all environment variables.

Prometheus#

To expose metrics for Prometheus to scrape, set:

export OTEL_METRICS_EXPORTER=prometheus
# Listen on all interfaces (the default is localhost), for example in a container
export OTEL_EXPORTER_PROMETHEUS_HOST=0.0.0.0
# Default port
export OTEL_EXPORTER_PROMETHEUS_PORT=9464

Metrics are then available at http://<host>:9464/metrics.

Metrics#

Metric	Type	Description	Attributes
`dd_checks`	Counter	Number of health checks	`domain`, `endpoint` (name of the endpoint), `ok` (`true` if the check passed)
`dd_api_calls`	Histogram	Duration of the calls to the DNS provider’s API, in milliseconds	`provider` (`awsroute53`, `azure`, `cloudflare`, `googleclouddns`, or `ovh`), `method`, `path`, `ok` (`true` if the call succeeded)

In Prometheus, the counter is named dd_checks_total. For example, this query shows the rate of failed checks for each endpoint:

sum by (domain, endpoint) (rate(dd_checks_total{ok="false"}[5m]))