Automating tasks using Git Hooks custom scripts

Automating tasks using Git Hooks custom scripts

Git hooks are custom scripts that automatically execute in response to specific Git events. These scripts help automate tasks such as code validation, testing, notifications, or enforcing workflows during Git operations like commits, pushes, pulls, merges, and more.

Types of Git Hooks

Git hooks are categorized into client-side and server-side hooks.

Client-Side Hooks

Run on your local machine when performing Git operations.

Examples:

pre-commit, post-merge, pre-push.

Server-Side Hooks

Run on the server when triggered by events, such as handling push events or repository changes.

Examples:

pre-receive, post-receive, update.

How Git Hooks Work

1. Trigger Event: Git hooks are triggered by specific Git events.

2. Execution: The hook script is executed, running custom logic.

3. Result: Based on the script output, Git may either proceed with the operation or terminate it.

Common Git Hooks

1. pre-commit:

   • Executes before a commit is made.

   • Used for tasks like code linting, testing, or checking for potential errors.

   Example:

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   1
   #!/bin/sh
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   echo "Running pre-commit hook..."
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   npm test
   

2. post-commit:

   • Executes after a commit is made.

   • Useful for tasks like sending notifications or updating other services.

   Example:

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   #!/bin/sh
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   echo "Commit made: $(git log -1 HEAD --format='%s')" >> commit-log.txt
   

3. pre-push:

   • Executes before changes are pushed to a remote repository.

   • Used for ensuring that builds pass, security scans, or code quality checks.

   Example:

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   #!/bin/sh
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   echo "Running pre-push hook..."
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   npm run build
   

4. post-receive (Server-side):

   • Executes after changes are pushed to a remote repository.

   • Can be used to trigger deployments or notify stakeholders.

Where to Place Git Hooks

Git hooks are placed in the .git/hooks/ directory inside your Git repository. For example:

• pre-commit: .git/hooks/pre-commit

• post-merge: .git/hooks/post-merge

How to Create and Enable Git Hooks

1. Create a Hook: Create a script file in the .git/hooks/ directory with the appropriate hook name (e.g., pre-commit, post-merge).

2. Make the Script Executable:

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   chmod +x .git/hooks/pre-commit
   

3. Add Logic: Add custom commands inside the script based on the desired task.

Example of a Simple Git Hook

pre-commit Hook Example:

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#!/bin/sh
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# pre-commit hook to run tests before committing
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npm run lint
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npm test

Benefits of Git Hooks

1. Automation: Streamlines repetitive tasks like testing, validation, and deployment.

2. Consistency: Ensures code quality and adherence to development standards.

3. Integration: Connects Git workflows with external tools (CI/CD pipelines, deployment systems).

Use Cases for Git Hooks

1. Code Quality: Automate linting, unit testing, and code reviews.

2. Branch Management: Enforce branch policies like pull request validations or release branching.

3. Deployment: Trigger builds, deployments, or notifications post-merge or post-push.