Configurable logfile analysis for your server.
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


gowatch provides configurable logfile analysis for your server. It is able to parse your logfiles and create summaries in formats ready for delivery via E-Mail or Web.

Build Status Go Report Card


Just go get the program. The following assumes that your GOPATH is set and your PATH contains your $GOPATH/bin directory; if not so, please read the Code Organization chapter of the go manual.

$ go get
$ gowatch
2015/04/08 19:10:44 No configuration file given. Specify one using `-c /path/to/config.yml`


gowatch will always run with a configuration file, pass it with the -c option:

gowatch -c /path/to/config.yml

Relative paths will always be resolved based on your current working directory. Note, that this also holds for paths inside the configuration file.

The configuration files itself are separated into three main sections: logfiles, mappers (not implemented yet) and summarizers. This reflects the architecture (see below).

An example configuration file would be

- filename: /var/log/auth.log
  tags: ['auth.log']
  with: {pattern: '%{SYSLOGBASE} %{GREEDYDATA:Message}'}
  where: {
    timestamp: {"younger than": "24h"}
- filename: /var/log/mail.log
  tags: ['mail.log']
  with: {pattern: '%{SYSLOGBASE} %{GREEDYDATA:Message}'}
  where: {
    timestamp: {"younger than": "24h"}

- do: count
  title: Sudoers
  where: {tags: {contains: 'auth.log'}}
  with: {
    '%{user}->%{effective_user}: %{command}': '\s*%{USER:user}\s*: TTY=%{DATA} ; PWD=%{PATH} ; USER=%{USER:effective_user} ; COMMAND=%{PATH:command}(: %{GREEDYDATA:arguments})?'
- do: count
  title: Stored Mails
  where: {tags: {contains: 'mail.log'}}
  with: {
    'Stored [%{mailboxname}]': "deliver\\(%{USER:user}\\): sieve: msgid=<%{DATA}>: stored mail into mailbox '%{DATA:mailboxname}'",

The configuration above would give the following output:

jon.doe->root: /bin/chown: 1
jon.doe->root: /bin/ln: 1
jon.doe->root: /bin/ls: 1
jon.doe->root: /bin/mv: 1
jon.doe->root: /home/jon.doe/workspace/go/bin/gowatch: 9
jon.doe->root: /usr/bin/less: 7
jon.doe->root: /usr/bin/vim: 9

Stored Mails
Stored [INBOX]: 20
Stored [Junk]: 24


The core of gowatch is the following pipeline.

  +------------+     +------------+     +------------+
  +   Parser   | --> |   Mapper   | --> | Summarizer |
  +------------+     +------------+     +------------+

While each parser.Parser creates logentry.LogEntry instances (by parsing logfiles) and sends them into the pipeline, the mapper.Mappers will modify these log entries and pass them to the summarizers. Each summary.Summarizer produces human readable output, e.g. by counting occurences or listing search results. The concatenation of output might then be given to the user, e.g. by mail.

The names are more specific than what Logstash uses, and this is by intention. The aim was to build an application specifically for creating reports from logfiles. Further usecases, like network support etc., are out of scope.

Related work

  • logwatch is widely used by Linux server administrators round the world, and so did I use it for many years. However, I find it to be not flexible enough in its configuration, and as soon as I want to change something, I always felt it was hard to extend and hard to change. Gowatch aims to be flexible, configurable and extendable.
  • logstash is a log processor, that became very popular in combination with the search serer elasticsearch. Those are really great tools, especially for usage in large server parks. However, they need several Gigabytes of RAM and that's just far too heavy for my small tiny server. Gowatch aims to be a small and easy-to-be-used tool with low requirements, just as logwatch always was.

3rd Party Libraries

Standing on the shoulders of giants, this wouldn't be what it is without:

  • gemsi/grok is a great Grok implementation in Go, throughoutly tested. Grok itself is a simple DRY method for log parsing, known from logstash, but there is also a standalone C implementation -- see for jordansissel/grok.
  • stretchr/testify brings assertions to Go, just the way they feel right. Great for testing!
  • go-yaml/yaml (un)marshalls YAML files into native Go data structures with few more than a single line of code. gowatch wouldn't have the configuration files it has without this library.

...among others. Thanks a lot for your work!


Licensed under MIT, see for LICENSE file.