This article explains how to install a bash script that posts a new message into a Slack channel when commits are pushed to your project’s git repository. Note that this implementation does not require the usage of GitHub, but rather git repositories hosted on your own servers.

Slack Git Integration with Single Commit

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Step 1: Create a bare repository

To create a new repository on your server named foo.git, first connect to your server, then run the following commands:

# Navigate on your server to the desired repository location
cd /desired/path

# Create the directory
mkdir foo.git

# Navigate inside the new directory
cd foo.git

# Initiate a bare git repository
git init --bare --shared=2664

--bare ensures that the repository only contains the version control information and doesn’t have any local files. This is necessary to be able to clone and push to the repository.
--shared=2664 sets the core.sharedRepository which forces git to do all new file creation with 2664 permissions. This helps to avoid issues with multiple people pushing to the repository.

If the foo.git repository already exists and you need to fix it, do the following:

# Navigate to the repository
cd /path/to/repo/foo.git

# Apply fixes
chgrp -R swdev * #may require sudo
chmod -R ug+rws * #may require sudo

Then edit the file /path/to/repo/foo.git/config
Under the [core] area, add or modify the following line:

sharedRepository = 2664

Step 2: Install script on the server

Download the bash script to your local machine.

Copy the file from your local machine to your project with the following command:

# Run command from your local machine (not on your server)
scp ~/local/path/to/file/post-receive @servername.com:/repo/path/on/server/foo.git/hooks/post-receive

Finally, change the permissions of the post-receive file on the server to allow it to be executable:

# Navigate to the repository's hooks folder on your server
cd /path/to/repo/on/server/foo.git/hooks

# Change permissions of the post-receive file
chmod +x post-receive

Step 3: Configuration

  1. Add an incoming WebHook to your Slack team: https://my.slack.com/services/new/incoming-webhook
  2. Make a copy of the WebHook URL https://hooks.slack.com/services/...
  3. Connect to your server and navigate to your repository. Add the WebHook URL via git config along with two other settings:
    # Navigate to repository
    cd /repo/path/on/server/foo.git
    
    # Add WebHook URL
    git config hooks.slack.webhook-url 'https://hooks.slack.com/services/...'
    
    # Set option to show all commits pushed
    git config hooks.slack.show-only-last-commit false
    
    # Set repository nice-name
    git config hooks.slack.repo-nice-name 'Our Awesome Project'
    

Step 4: Set Options (run commands within repo on your server)

Listed below are the other settings that are configurable. Most of these can also be setup when configuring the Incoming WebHook on Slack, so by not setting them here, they default to the Slack settings. It’s recommended to not set these options here (unless listed in Step 3) so that the default WebHook settings are applied.

Specify a channel/user to post to in Slack instead of the WebHook’s default:

git config hooks.slack.channel '#channel'
    '#channel' - Post to channel
    '@username' - Direct message from @slackbot to user
    'groupname' - Post to group

Specify a username to post as. If not specified, the default name will be used that was created on Slack:

git config hooks.slack.username 'Marty McFly'

Specify an image to display in Slack instead of the default icon:

git config hooks.slack.icon-url 'https://cdn4.iconfinder.com/data/icons/btf_LIN/LIN/256/delorean.png'

Specify an emoji to display in Slack instead of the default icon:

git config hooks.slack.icon-emoji ':ghost:'

Specify a repository nice-name that will be shown in messages:

git config hooks.slack.repo-nice-name 'Our Awesome Project'

Specify whether you want to show only the last commit (or all commits) when pushing multiple commits:

git config hooks.slack.show-only-last-commit true

Specify if you only want certain branches of the repository:

git config hooks.slack.branch-regexp regexp

Examples

An example of a single commit message:

Slack Git Integration with Single Commit

An example of multiple commit messages (with git config hooks.slack.show-only-last-commit set to false):

Slack Git Integration with Multiple Commits