How to setup git server on ubuntu with push email notifications

Posted on 4 mins read

Git Server

Prerequisites are git and ssh-server (apt-get install openssh-server).

The installation process is described in the Pro Git book. Below is the setup process with some comments and updates.

Add git user, set some password (you will be asked for it):

    $ sudo adduser git

Log in as git user and setup authorized ssh keys:

    $ su git
    git@localname$ cd ~
    git@localname$ mkdir .ssh

For each user who need an access to the server add user’s public key into ~/.ssh/authorized_keys to generate new key-pair for the user use ssh-keygen see github manual for details.

    git@localname$ cat /home/usera/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
    git@localname$ cat /home/userb/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

Change permissions for .ssh folder and authorized_keys file:

    git@localname$ chmod 600 ~/.ssh/authorized_keys
    git@localname$ chmod 755 ~/.ssh

Make a dir for repositories and init bare repositories:

    git@localname$ mkdir ~/server
    git@localname$ cd server
    git@localname$ mkdir project.git
    git@localname$ cd project.git
    git@localname$ git --bare init

Sequrity - set git-shell for the git user:

    # check where git-shell is
    $ which git-shell
    /usr/bin/git-shell

    # edit the etc/passwd
    $ sudo vim /etc/passwd

    # find the string for git user:
        git❌1000:1000::/home/git:/bin/sh
    # change shell for git user:
        git❌1000:1000::/home/git:/usr/bin/git-shell

On the user side - clone the repository or add a remote to existing repository:

    # clone
    $ git clone ssh://git@server.host.name/home/git/server/project.git

    # or add remote
    $ cd project
    $ git remote add origin ssh://git@server.host.name/home/git/server/project.git

For ‘server.host.name’ there are several options:

  • if the server has a domain name then just use it
  • use sever IP address instead of host name
  • use any host name you like and add it to local hosts file to map to the IP address

Possible problems and solutions

git-shell shows the “Interactive git shell is not enabled.”

This is OK and it will work, additional setup can be done to allow the git user to log-in via ssh and execute special commands like “list” to get repository listing. See:

When the user tries to execute a server operation git asks for git user password instead of ssh key passphrase.

Check auth log (/var/log/auth.log) for errors. In my case there were errors related to git user’s .ssh and authorized_keys permissions:

    Aug 15 15:25:24 seb-ubu sshd[4561]: Authentication refused: bad ownership or modes for file /home/git/.ssh/authorized_keys
    ...
    Aug 15 15:47:48 seb-ubu sshd[7145]: Authentication refused: bad ownership or modes for directory /home/git/.ssh

Changing access permissions as described above fixed the issue.

How to make existing git repository bare

If you already have a repository and want to put it on the server then it seems to be safe to just copy the .git folder from the existing repository:

    # source: project/.git
    $ cp -r project/.git project.git
    $ cd project.git
    $ git config --bool core.bare true

Git Server - email notifications on push

Git already has a script to handle email notifications after push. Check the /usr/share/doc/git/contrib/hooks/post-receive-email for instructions:

    $ sudo chmod a+x /usr/share/git-core/contrib/hooks/post-receive-email
    $ cd /path/to/your/repository.git
    $ ln -sf /usr/share/git-core/contrib/hooks/post-receive-email hooks/post-receive

Configure notifications:

    $ cd /path/to/your/repository.git

    # who should receive notifications
    $ git config hooks.mailinglist "user1@example.com user2@example.com"

    # send emails from
    $ git config hooks.envelopesender git@myserver.com

    # email subject prefix
    $ git config hooks.emailprefix "[Git]"

    # project name - edit 'description' file in the git repository folder
    $ vim description

The post-receive-email script requires sendmail to work. Below is a description of the sendmail setup process.

Setup sendmail on Ubuntu

Install it:

    $ sudo apt-get install sendmail

Check your hosts file - in my case sendmail was incredibly slow and this was fixed by following line in /etc/hosts:

    127.0.0.1 localhost.localdomain localhost myhostname <--- order matters!!!

Note that you need to use the same order as above - localhost.localdomain, localhost and then myhostname (replace myhostname with your real host name, check the output of ‘hostname’ command).

Send a test email:

    $ echo "My test email being sent from sendmail" | /usr/sbin/sendmail myemail@domain.com

If you have problems with emails then check the log: /var/log/mail.log and error log: /var/log/mail.err.

Setup SMTP for sendmail

If you want to setup SMTP server for you emails do the following:

    $ cd /etc/mail
    $ sudo mkdir auth
    $ sudo chmod 700 auth
    $ sudo vim client-info

Enter following line into the client-info file:

    AuthInfo:smtp.server.com "U:mymail@server.com" "I:mymail@server.com" "P:mypassword"

Here you put you smtp server name (instead of ‘smtp.server.com’) and your credentials. ‘U’ is an smtp user (usually your email), ‘I’ is an account (usually also your email) and ‘P’ is a password. See details for parameters here.

Continue setup:

    $ sudo bash -c "makemap hash client-info < client-info"

Edit the /etc/mail/sendmail.mc and add following lines before the “MAILER_DEFINITIONS” line:

    define('SMART_HOST','smtp.server.com')dnl
    define('confAUTH_MECHANISMS', 'EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
    FEATURE('authinfo','hash /etc/mail/auth/client-info')dnl

Process the sendmail.mc with m4:

    $ sudo bash -c "m4 sendmail.mc > sendmail.cf"

Restart sendmail:

    $ sudo service sendmail restart

Resources:

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