This repository provides code for a Prometheus metrics exporter
for the Postfix mail server. This exporter
provides histogram metrics for the size and age of messages stored in
the mail queue. It extracts these metrics from Postfix by connecting to
a UNIX socket under /var/spool.
In addition to that, it counts events by parsing Postfix's log file, using regular expression matching. It truncates the log file when processed, so that the next iteration doesn't interpret the same lines twice. It makes sense to configure your syslogger to multiplex log entries to a second file:
mail.* -/var/log/postfix_exporter_input.log
Command line arguments are:
-postfix.logfile_path string
Path where Postfix writes log entries. This file will be truncated by this exporter. (default "/var/log/postfix_exporter_input.log")
-postfix.showq_path string
Path at which Postfix places its showq socket. (default "/var/spool/postfix/public/showq")
-web.listen-address string
Address to listen on for web interface and telemetry. (default ":9154")
-web.telemetry-path string
Path under which to expose metrics. (default "/metrics")
You can create a Docker image by running the following:
make docker
This will create the image postfix-exporter:latest, which you can then tag
and push appropriately to Docker Hub.
By default the image doesn't provide a Postfix installation so you can test by using the host systems' Postfix UNIX socket in the following manner:
docker run -it --rm \
-v /var/spool/postfix/public/showq:/var/spool.postfix/public/showq \
-p 9154:9154 \
postfix-exporter:latest
Then you could be able to access the metrics from the host:
curl http://localhost:9154/metrics