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GitHub Actions is a powerful tool for automating workflows directly within your GitHub repositories. One common use case is to send notifications to a Slack channel whenever specific events occur in your repository, such as successful builds, failed tests, or completed deployments. This guide will show you how to set up detailed Slack notifications using GitHub Actions, complete with examples to help you get started.
Integrating Slack notifications with GitHub Actions is beneficial for several reasons:
Before we dive into the setup, ensure you have the following:
To send notifications to Slack, you need to create a webhook URL through the Slack API.
Create a Slack App:
2. Create an Incoming Webhook:
Now that you have a Slack Webhook URL, you can create a GitHub Actions workflow to send notifications.
.github/workflows/
directory: If your repository doesn’t have this directory, create it in the root of your project..github/workflows/
directory. For example, you can name it slack-notifications.yml
.main
branch.name: Send Slack Notification
on:
push:
branches:
- main
jobs:
notify:
runs-on: ubuntu-latest
steps:
- name: Send Slack Notification
env:
SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
run: |
curl -X POST -H 'Content-type: application/json' --data '{"text":"A new push has been made to the main branch."}' $SLACK_WEBHOOK_URL
To keep your Slack Webhook URL secure, store it as a GitHub Secret.
Settings > Secrets and variables > Actions
.SLACK_WEBHOOK_URL
and paste your Webhook URL into the value field.The example above sends a very basic message. However, Slack messages can be much more detailed and formatted using Block Kit.
Example of a Detailed Slack Notification:
name: Send Detailed Slack Notification
on:
push:
branches:
- main
jobs:
notify:
runs-on: ubuntu-latest
steps:
- name: Send Detailed Slack Notification
env:
SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
run: |
curl -X POST -H 'Content-type: application/json' --data '{
"blocks": [
{
"type": "section",
"text": {
"type": "mrkdwn",
"text": "*New Push to Main Branch*"
}
},
{
"type": "section",
"fields": [
{
"type": "mrkdwn",
"text": "*Repository:*\n'${{ github.repository }}'"
},
{
"type": "mrkdwn",
"text": "*Branch:*\n'${{ github.ref }}'"
},
{
"type": "mrkdwn",
"text": "*Commit Message:*\n'${{ github.event.head_commit.message }}'"
},
{
"type": "mrkdwn",
"text": "*Committer:*\n'${{ github.event.head_commit.committer.name }}'"
}
]
}
]
}' $SLACK_WEBHOOK_URL
Explanation:
${{ github.repository }}
, ${{ github.ref }}
, and other GitHub context variables to dynamically insert information into the Slack message.
This will send a detailed notification to your Slack channel every time there’s a push to the main
branch, including information like the repository name, branch, commit message, and committer.
GitHub Actions can be triggered by various events beyond just a push to a branch. Some common triggers include:
Pull Requests:
on:
pull_request:
branches:
- main
Workflow Failures:
on:
workflow_run:
workflows: ["CI"]
types:
- completed
Scheduled Events:
on:
schedule:
- cron: '0 9 * * 1' # Every Monday at 9 AM
Example for Workflow Failure Notification: This example sends a notification only if a workflow fails.
name: Notify on Failure
on:
workflow_run:
workflows: ["CI"]
types:
- completed
jobs:
notify_on_failure:
if: ${{ failure() }}
runs-on: ubuntu-latest
steps:
- name: Notify Slack on Failure
env:
SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
run: |
curl -X POST -H 'Content-type: application/json' --data '{
"text": ":x: *CI Workflow Failed*",
"blocks": [
{
"type": "section",
"text": {
"type": "mrkdwn",
"text": "*Workflow:* CI\n*Status:* Failed\n*Repository:* ${{ github.repository }}"
}
}
]
}' $SLACK_WEBHOOK_URL
This sends a failure notification with details about the workflow and the repository, ensuring your team is immediately aware of any issues.
You may want to send different notifications depending on the type of event or the result of the action. For instance, you might want to send one type of message for a successful build and another for a failure.
Example: Conditional Notifications:
name: Notify on Success or Failure
on:
push:
branches:
- main
jobs:
build:
runs-on: ubuntu-latest
steps:
- name: Checkout Code
uses: actions/checkout@v2
- name: Run Tests
run: |
echo "Running tests..."
# Simulate a test failure
exit 1
notify:
needs: build
runs-on: ubuntu-latest
steps:
- name: Notify Slack
env:
SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
run: |
if [ "${{ needs.build.result }}" == "success" ]; then
curl -X POST -H 'Content-type: application/json' --data '{"text":"Build Succeeded!"}' $SLACK_WEBHOOK_URL;
else
curl -X POST -H 'Content-type: application/json' --data '{"text":"Build Failed!"}' $SLACK_WEBHOOK_URL;
fi
In this example, the notification is sent based on whether the build was successful or failed.
To ensure that your Slack notifications from GitHub Actions are effective, follow these best practices: