git-multimail ============= git-multimail is a tool for sending notification emails on pushes to a Git repository. It includes a Python module called git_multimail.py, which can either be used as a hook script directly or can be imported as a Python module into another script. git-multimail is derived from the Git project's old contrib/hooks/post-receive-email, and is mostly compatible with that script. See README.migrate-from-post-receive-email for details about the differences and for how to migrate from post-receive-email to git-multimail. git-multimail, like the rest of the Git project, is licensed under GPLv2 (see the COPYING file for details). Please note: although, as a convenience, git-multimail may be distributed along with the main Git project, development of git-multimail takes place in its own, separate project. See section "Getting involved" below for more information. By default, for each push received by the repository, git-multimail: 1. Outputs one email summarizing each reference that was changed. These "reference change" (called "refchange" below) emails describe the nature of the change (e.g., was the reference created, deleted, fast-forwarded, etc.) and include a one-line summary of each commit that was added to the reference. 2. Outputs one email for each new commit that was introduced by the reference change. These "commit" emails include a list of the files changed by the commit, followed by the diffs of files modified by the commit. The commit emails are threaded to the corresponding reference change email via "In-Reply-To". This style (similar to the "git format-patch" style used on the Git mailing list) makes it easy to scan through the emails, jump to patches that need further attention, and write comments about specific commits. Commits are handled in reverse topological order (i.e., parents shown before children). For example, [git] branch master updated + [git] 01/08: doc: fix xref link from api docs to manual pages + [git] 02/08: api-credentials.txt: show the big picture first + [git] 03/08: api-credentials.txt: mention credential.helper explicitly + [git] 04/08: api-credentials.txt: add "see also" section + [git] 05/08: t3510 (cherry-pick-sequence): add missing '&&' + [git] 06/08: Merge branch 'rr/maint-t3510-cascade-fix' + [git] 07/08: Merge branch 'mm/api-credentials-doc' + [git] 08/08: Git 1.7.11-rc2 Each commit appears in exactly one commit email, the first time that it is pushed to the repository. If a commit is later merged into another branch, then a one-line summary of the commit is included in the reference change email (as usual), but no additional commit email is generated. By default, reference change emails have their "Reply-To" field set to the person who pushed the change, and commit emails have their "Reply-To" field set to the author of the commit. 3. Output one "announce" mail for each new annotated tag, including information about the tag and optionally a shortlog describing the changes since the previous tag. Such emails might be useful if you use annotated tags to mark releases of your project. Requirements ------------ * Python 2.x, version 2.4 or later. No non-standard Python modules are required. git-multimail does *not* currently work with Python 3.x. The example scripts invoke Python using the following shebang line (following PEP 394 [1]): #! /usr/bin/env python2 If your system's Python2 interpreter is not in your PATH or is not called "python2", you can change the lines accordingly. Or you can invoke the Python interpreter explicitly, for example via a tiny shell script like #! /bin/sh /usr/local/bin/python /path/to/git_multimail.py "$@" * The "git" command must be in your PATH. git-multimail is known to work with Git versions back to 1.7.1. (Earlier versions have not been tested; if you do so, please report your results.) * To send emails using the default configuration, a standard sendmail program must be located at '/usr/sbin/sendmail' and configured correctly to send emails. If this is not the case, see the multimailhook.mailer configuration variable below for how to configure git-multimail to send emails via an SMTP server. Invocation ---------- git_multimail.py is designed to be used as a "post-receive" hook in a Git repository (see githooks(5)). Link or copy it to $GIT_DIR/hooks/post-receive within the repository for which email notifications are desired. Usually it should be installed on the central repository for a project, to which all commits are eventually pushed. For use on pre-v1.5.1 Git servers, git_multimail.py can also work as an "update" hook, taking its arguments on the command line. To use this script in this manner, link or copy it to $GIT_DIR/hooks/update. Please note that the script is not completely reliable in this mode [2]. Alternatively, git_multimail.py can be imported as a Python module into your own Python post-receive script. This method is a bit more work, but allows the behavior of the hook to be customized using arbitrary Python code. For example, you can use a custom environment (perhaps inheriting from GenericEnvironment or GitoliteEnvironment) to * change how the user who did the push is determined * read users' email addresses from an LDAP server or from a database * decide which users should be notified about which commits based on the contents of the commits (e.g., for users who want to be notified only about changes affecting particular files or subdirectories) Or you can change how emails are sent by writing your own Mailer class. The "post-receive" script in this directory demonstrates how to use git_multimail.py as a Python module. (If you make interesting changes of this type, please consider sharing them with the community.) Configuration ------------- By default, git-multimail mostly takes its configuration from the following "git config" settings: multimailhook.environment This describes the general environment of the repository. Currently supported values: "generic" -- the username of the pusher is read from $USER and the repository name is derived from the repository's path. "gitolite" -- the username of the pusher is read from $GL_USER and the repository name from $GL_REPO. If neither of these environments is suitable for your setup, then you can implement a Python class that inherits from Environment and instantiate it via a script that looks like the example post-receive script. The environment value can be specified on the command line using the --environment option. If it is not specified on the command line or by multimailhook.environment, then it defaults to "gitolite" if the environment contains variables $GL_USER and $GL_REPO; otherwise "generic". multimailhook.repoName A short name of this Git repository, to be used in various places in the notification email text. The default is to use $GL_REPO for gitolite repositories, or otherwise to derive this value from the repository path name. multimailhook.mailinglist The list of email addresses to which notification emails should be sent, as RFC 2822 email addresses separated by commas. This configuration option can be multivalued. Leave it unset or set it to the empty string to not send emails by default. The next few settings can be used to configure specific address lists for specific types of notification email. multimailhook.refchangeList The list of email addresses to which summary emails about reference changes should be sent, as RFC 2822 email addresses separated by commas. This configuration option can be multivalued. The default is the value in multimailhook.mailinglist. Set this value to the empty string to prevent reference change emails from being sent. multimailhook.announceList The list of email addresses to which emails about new annotated tags should be sent, as RFC 2822 email addresses separated by commas. This configuration option can be multivalued. The default is the value in multimailhook.refchangelist or multimailhook.mailinglist. Set this value to the empty string to prevent annotated tag announcement emails from being sent. multimailhook.commitList The list of email addresses to which emails about individual new commits should be sent, as RFC 2822 email addresses separated by commas. This configuration option can be multivalued. The default is the value in multimailhook.mailinglist. Set this value to the empty string to prevent notification emails about individual commits from being sent. multimailhook.announceShortlog If this option is set to true, then emails about changes to annotated tags include a shortlog of changes since the previous tag. This can be useful if the annotated tags represent releases; then the shortlog will be a kind of rough summary of what has happened since the last release. But if your tagging policy is not so straightforward, then the shortlog might be confusing rather than useful. Default is false. multimailhook.refchangeShowLog If this option is set to true, then summary emails about reference changes will include a detailed log of the added commits in addition to the one line summary. The log is generated by running "git log" with the options specified in multimailhook.logOpts. Default is false. multimailhook.mailer This option changes the way emails are sent. Accepted values are: - sendmail (the default): use the command /usr/sbin/sendmail or /usr/lib/sendmail (or sendmailCommand, if configured). This mode can be further customized via the following options: multimailhook.sendmailCommand The command used by mailer "sendmail" to send emails. Shell quoting is allowed in the value of this setting, but remember that Git requires double-quotes to be escaped; e.g., git config multimailhook.sendmailcommand '/usr/sbin/sendmail -t -F \"Git Repo\"' Default is '/usr/sbin/sendmail -t' or '/usr/lib/sendmail -t' (depending on which file is present and executable). multimailhook.envelopeSender If set then pass this value to sendmail via the -f option to set the envelope sender address. - smtp: use Python's smtplib. This is useful when the sendmail command is not available on the system. This mode can be further customized via the following options: multimailhook.smtpServer The name of the SMTP server to connect to. The value can also include a colon and a port number; e.g., "mail.example.com:25". Default is 'localhost' using port 25. multimailhook.envelopeSender The sender address to be passed to the SMTP server. If unset, then the value of multimailhook.from is used. multimailhook.from If set then use this value in the From: field of generated emails. If unset, then use the repository's user configuration (user.name and user.email). If user.email is also unset, then use multimailhook.envelopeSender. multimailhook.administrator The name and/or email address of the administrator of the Git repository; used in FOOTER_TEMPLATE. Default is multimailhook.envelopesender if it is set; otherwise a generic string is used. multimailhook.emailPrefix All emails have this string prepended to their subjects, to aid email filtering (though filtering based on the X-Git-* email headers is probably more robust). Default is the short name of the repository in square brackets; e.g., "[myrepo]". multimailhook.emailMaxLines The maximum number of lines that should be included in the body of a generated email. If not specified, there is no limit. Lines beyond the limit are suppressed and counted, and a final line is added indicating the number of suppressed lines. multimailhook.emailMaxLineLength The maximum length of a line in the email body. Lines longer than this limit are truncated to this length with a trailing " [...]" added to indicate the missing text. The default is 500, because (a) diffs with longer lines are probably from binary files, for which a diff is useless, and (b) even if a text file has such long lines, the diffs are probably unreadable anyway. To disable line truncation, set this option to 0. multimailhook.maxCommitEmails The maximum number of commit emails to send for a given change. When the number of patches is larger that this value, only the summary refchange email is sent. This can avoid accidental mailbombing, for example on an initial push. To disable commit emails limit, set this option to 0. The default is 500. multimailhook.emailStrictUTF8 If this boolean option is set to "true", then the main part of the email body is forced to be valid UTF-8. Any characters that are not valid UTF-8 are converted to the Unicode replacement character, U+FFFD. The default is "true". multimailhook.diffOpts Options passed to "git diff-tree" when generating the summary information for ReferenceChange emails. Default is "--stat --summary --find-copies-harder". Add -p to those options to include a unified diff of changes in addition to the usual summary output. Shell quoting is allowed; see multimailhook.logOpts for details. multimailhook.logOpts Options passed to "git log" to generate additional info for reference change emails (used only if refchangeShowLog is set). For example, adding --graph will show the graph of revisions, -p will show the complete diff, etc. The default is empty. Shell quoting is allowed; for example, a log format that contains spaces can be specified using something like: git config multimailhook.logopts '--pretty=format:"%h %aN <%aE>%n%s%n%n%b%n"' If you want to set this by editing your configuration file directly, remember that Git requires double-quotes to be escaped (see git-config(1) for more information): [multimailhook] logopts = --pretty=format:\"%h %aN <%aE>%n%s%n%n%b%n\" multimailhook.emailDomain Domain name appended to the username of the person doing the push to convert it into an email address (via "%s@%s" % (username, emaildomain)). More complicated schemes can be implemented by overriding Environment and overriding its get_pusher_email() method. multimailhook.replyTo multimailhook.replyToCommit multimailhook.replyToRefchange Addresses to use in the Reply-To: field for commit emails (replyToCommit) and refchange emails (replyToRefchange). multimailhook.replyTo is used as default when replyToCommit or replyToRefchange is not set. The value for these variables can be either: - An email address, which will be used directly. - The value "pusher", in which case the pusher's address (if available) will be used. This is the default for refchange emails. - The value "author" (meaningful only for replyToCommit), in which case the commit author's address will be used. This is the default for commit emails. - The value "none", in which case the Reply-To: field will be omitted. Email filtering aids -------------------- All emails include extra headers to enable fine tuned filtering and give information for debugging. All emails include the headers "X-Git-Repo", "X-Git-Refname", and "X-Git-Reftype". ReferenceChange emails also include headers "X-Git-Oldrev" and "X-Git-Newrev"; Revision emails also include header "X-Git-Rev". Customizing email contents -------------------------- git-multimail mostly generates emails by expanding templates. The templates can be customized. To avoid the need to edit git_multimail.py directly, the preferred way to change the templates is to write a separate Python script that imports git_multimail.py as a module, then replaces the templates in place. See the provided post-receive script for an example of how this is done. Customizing git-multimail for your environment ---------------------------------------------- git-multimail is mostly customized via an "environment" that describes the local environment in which Git is running. Two types of environment are built in: * GenericEnvironment: a stand-alone Git repository. * GitoliteEnvironment: a Git repository that is managed by gitolite [3]. For such repositories, the identity of the pusher is read from environment variable $GL_USER, and the name of the repository is read from $GL_REPO (if it is not overridden by multimailhook.reponame). By default, git-multimail assumes GitoliteEnvironment if $GL_USER and $GL_REPO are set, and otherwise assumes GenericEnvironment. Alternatively, you can choose one of these two environments explicitly by setting a "multimailhook.environment" config setting (which can have the value "generic" or "gitolite") or by passing an --environment option to the script. If you need to customize the script in ways that are not supported by the existing environments, you can define your own environment class class using arbitrary Python code. To do so, you need to import git_multimail.py as a Python module, as demonstrated by the example post-receive script. Then implement your environment class; it should usually inherit from one of the existing Environment classes and possibly one or more of the EnvironmentMixin classes. Then set the "environment" variable to an instance of your own environment class and pass it to run_as_post_receive_hook(). The standard environment classes, GenericEnvironment and GitoliteEnvironment, are in fact themselves put together out of a number of mixin classes, each of which handles one aspect of the customization. For the finest control over your configuration, you can specify exactly which mixin classes your own environment class should inherit from, and override individual methods (or even add your own mixin classes) to implement entirely new behaviors. If you implement any mixins that might be useful to other people, please consider sharing them with the community! Getting involved ---------------- git-multimail is an open-source project, built by volunteers. We would welcome your help! The current maintainer is Michael Haggerty <mhagger@alum.mit.edu>. General discussion of git-multimail takes place on the main Git mailing list, git@vger.kernel.org Please CC emails regarding git-multimail to me so that I don't overlook them. The git-multimail project itself is currently hosted on GitHub: https://github.com/mhagger/git-multimail We use the GitHub issue tracker to keep track of bugs and feature requests, and GitHub pull requests to exchange patches (though, if you prefer, you can send patches via the Git mailing list with cc to me). Please note that although a copy of git-multimail will probably be distributed in the "contrib" section of the main Git project, development takes place in the separate git-multimail repository on GitHub! (Whenever enough changes to git-multimail have accumulated, a new code-drop of git-multimail will be submitted for inclusion in the Git project.) Footnotes --------- [1] http://www.python.org/dev/peps/pep-0394/ [2] Because of the way information is passed to update hooks, the script's method of determining whether a commit has already been seen does not work when it is used as an "update" script. In particular, no notification email will be generated for a new commit that is added to multiple references in the same push. [3] https://github.com/sitaramc/gitolite