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Rohan McGovern > Gerrit-Client-20121123 > Gerrit::Client



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Module Version: 20121123   Source   Latest Release: Gerrit-Client-20140611


Gerrit::Client - interact with Gerrit code review tool


  use AnyEvent;
  use Gerrit::Client qw(stream_events);

  # alert me when new patch sets arrive in
  # ssh://
  my $stream = stream_events(
    url => 'ssh://',
    on_event => sub {
      my (undef, $event) = @_;
      if ($event->{type} eq 'patchset-added'
          && $event->{change}{project} eq 'myproject') {
        system("xmessage", "New patch set arrived!");

  AE::cv()->recv(); # must run an event loop for callbacks to be activated

This module provides some utility functions for interacting with the Gerrit code review tool.

This module is an AnyEvent user and may be used with any event loop supported by AnyEvent.


stream_events url => $gerrit_url, ...

Connect to "gerrit stream-events" on the given gerrit host and register one or more callbacks for events. Returns an opaque handle to the stream-events connection; the connection will be aborted if the handle is destroyed.

$gerrit_url should be a URL with ssh schema referring to a valid Gerrit installation (e.g. "ssh://").

Supported callbacks are documented below. All callbacks receive the stream-events handle as their first argument.

on_event => $cb->($handle, $data)

Called when an event has been received. $data is a reference to a hash representing the event.

See the Gerrit documentation for information on the possible events.

on_error => $cb->($handle, $error)

Called when an error occurs in the connection. $error is a human-readable string.

Examples of errors include network disruptions between your host and the Gerrit server, or the ssh process being killed unexpectedly. Receiving any kind of error means that some Gerrit events may have been lost.

If this callback returns a true value, stream_events will attempt to reconnect to Gerrit and resume processing; otherwise, the connection is terminated and no more events will occur.

The default error callback will warn and return 1, retrying on all errors.


Returns a random Change-Id (the character 'I' followed by 40 hexadecimal digits), suitable for usage as the Change-Id field in a commit to be pushed to gerrit.


Returns the 'next' Change-Id which should be used for a commit created by the current git author/committer (which should be set by git_environment prior to calling this method). The current working directory must be within a git repository.

This method is suitable for usage within a script which periodically creates commits for review, but should have only one outstanding review (per branch) at any given time. The returned Change-Id is (hopefully) unique, and stable; it only changes when a new commit arrives in the git repository from the current script.

For example, consider a script which is run once per day to clone a repository, generate a change and push it for review. If this function is used to generate the Change-Id on the commit, the script will update the same change in gerrit until that change is merged. Once the change is merged, next_change_id returns a different value, resulting in a new change. This ensures the script has a maximum of one pending review any given time.

If any problems occur while determining the next Change-Id, a warning is printed and a random Change-Id is returned.

git_environment(name => $name, email => $email, author_only => [0|1] )

Returns a copy of %ENV modified suitably for the creation of git commits by a script/bot.



The human-readable name used for git commits. Mandatory.


The email address used for git commits. Mandatory.


If 1, the environment is only modified for the git author, and not the git committer. Depending on the gerrit setup, this may be required to avoid complaints about missing "Forge Identity" permissions.

Defaults to 0.

When generating commits for review in gerrit, this method may be used in conjunction with "next_change_id" to ensure this bot has only one outstanding change for review at any time, as in the following example:

    local %ENV = git_environment(
        name => 'Indent Bot',
        email => '',

    # fix up indenting in all the .cpp files
    (system('indent *.cpp') == 0) || die 'indent failed';

    # then commit and push them; commits are authored and committed by
    # 'Indent Bot <>'.  usage of next_change_id()
    # ensures that this bot has a maximum of one outstanding change for
    # review
    my $message = "Fixed indentation\n\nChange-Id: ".next_change_id();
    (system('git add -u *.cpp') == 0)
      || die 'git add failed';
    (system('git', 'commit', '-m', $message) == 0)
      || die "git commit failed";
    (system('git push gerrit HEAD:refs/for/master') == 0)
      || die "git push failed";
review $commit_or_change, url => $gerrit_url, ...

Wrapper for the `gerrit review' command; add a comment and/or update the status of a change in gerrit.

$commit_or_change is mandatory, and is either a git commit (in abbreviated or full 40-digit form), or a gerrit change number and patch set separated by a comment (e.g. 3404,3 refers to patch set 3 of the gerrit change accessible at The latter form is deprecated and may be removed in some version of gerrit.

$gerrit_url is also mandatory and should be a URL with ssh schema referring to a valid Gerrit installation (e.g. "ssh://"). The URL may optionally contain the relevant gerrit project.

All other arguments are optional, and include:

on_success => $cb->( $commit_or_change )
on_error => $cb->( $commit_or_change, $error )

Callbacks invoked when the operation succeeds or fails.

abandon => 1|0
message => $string
project => $string
restore => 1|0
stage => 1|0
submit => 1|0
code_review => $number
sanity_review => $number
verified => $number

These options are passed to the `gerrit review' command. For information on their usage, please see the output of `gerrit review --help' on your gerrit installation, or see the Gerrit documentation.

Note that certain options can be disabled on a per-site basis. `gerrit review --help' will show only those options which are enabled on the given site.



The ssh command and initial arguments used when Gerrit::Client invokes ssh.

  # force IPv6 for this connection
  local @Gerrit::Client::SSH = ('ssh', '-oAddressFamily=inet6');
  my $stream = Gerrit::Client::stream_events ...

The default value is ('ssh').


Rohan McGovern, <>


Please use to view or report bugs.


Copyright (C) 2012 Rohan McGovern <>

Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies)

This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License version 2.1 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

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