From 77dfb9449939cceb272d6b3b36523ae1d8114ea5 Mon Sep 17 00:00:00 2001 From: Silke Date: Tue, 13 Feb 2018 11:15:04 +0100 Subject: [PATCH] Document systemd usage --- README.md | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/README.md b/README.md index d14ea70..5deb19a 100644 --- a/README.md +++ b/README.md @@ -6,8 +6,16 @@ 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 +In addition to that, it counts events by parsing Postfix's log entries, +using regular expression matching. +The log entries are retrieved from the systemd journal or from a log file. + +Please refer to this utility's `main()` function for a list of supported +command line flags. + +## Events from log file + +The log file is truncated 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: @@ -16,8 +24,11 @@ entries to a second file: mail.* -/var/log/postfix_exporter_input.log ``` -There is also an option to collect the metrics via the systemd journal instead of a log file. +The path to the log file is specified with the `-postfix.logfile_path` flag. +## Events from systemd -Please refer to this utility's `main()` function for a list of supported -command line flags. +Retrieval from the systemd journal is enabled with the `-systemd.enable` flag. +This overrides the log file setting. +It is possible to specify the unit (with `-systemd.unit`) or slice (with `-systemd.slice`). +Additionally, it is possible to read the journal from a directory with the `-systemd.journal_path` flag.