GitLab CI/CD Variables

GitLab CI/CD variables allow you to customize your CI/CD pipelines by defining and managing key values used in the build, deployment, and operational processes. These variables act as placeholders for dynamic data, such as environment-specific settings, sensitive information like passwords, or any other data that might change across different stages or jobs within your pipelines.

In this article, we will walk you through everything you need to know about GitLab CI/CD variables, including how to define, manage, and use them effectively.

What are GitLab CI/CD Variables?

GitLab CI/CD variables are key-value pairs that you can use to control the behaviour of your CI/CD pipelines. They can be defined at various levels, including project, group, or instance levels, and can be scoped to specific environments. Variables are used for various purposes, such as:

• Storing sensitive information (e.g., API keys, passwords).
• Defining environment-specific settings (e.g., database URLs).
• Managing pipeline configuration dynamically (e.g., toggling feature flags).

Types of GitLab CI/CD Variables

GitLab CI/CD variables come in several types, each serving different purposes and offering varying levels of security and flexibility:

• Environment Variables: These variables are available during the execution of CI/CD jobs. They are commonly used for storing values that differ between environments, like production or staging.
• File Variables: These variables store content as files rather than simple key-value pairs. They are useful when you need to handle certificates or configuration files securely.
• Protected Variables: Protected variables are restricted to running on protected branches or tags, adding a layer of security by preventing unauthorized access during job execution.
• Masked Variables: Masked variables hide their values in job logs, ensuring that sensitive information like passwords or API keys are not exposed.
• CI/CD Pipeline Variables: These are variables that you define directly within your pipeline configuration file (.gitlab-ci.yml). They can be defined globally or scoped to specific jobs or stages.

Defining GitLab CI/CD Variables

You can define GitLab CI/CD variables at various levels in your GitLab hierarchy:

• Project Level: Define variables that are specific to a single project.
• Group Level: Define variables that can be inherited by all projects within a group.
• Instance Level: Define variables that are accessible to all projects and groups within the GitLab instance.

Defining Variables in the GitLab UI

1. Project Level:

• Go to your project's Settings > CI/CD.
• Expand the Variables section.
• Click Add Variable.
• Enter the variable key and value.
• Configure options like Protected and Masked based on your security needs.
• Click Add Variable to save.

2. Group Level:

• Go to your group's Settings > CI/CD.
• Expand the Variables section and follow the same steps as for project-level variables.

3. Instance Level:

• Requires admin access. Go to Admin Area > Settings > CI/CD and define variables in the Variables section.

Defining Variables in the .gitlab-ci.yml File

Variables can also be defined directly in your .gitlab-ci.yml file, either globally or within specific jobs:

Global Variables:

variables:
  GLOBAL_VAR: "global_value"

Job-Specific Variables:

job_name:
  script:
    - echo "Running job"
  variables:
    JOB_SPECIFIC_VAR: "job_value"

Using GitLab CI/CD Variables

Once defined, you can use CI/CD variables within your pipeline jobs by referencing them in your scripts, commands, or within other configuration settings:

Accessing Variables in Scripts:

job_name:
  script:
    - echo "The value of GLOBAL_VAR is $GLOBAL_VAR"
    - echo "The value of JOB_SPECIFIC_VAR is $JOB_SPECIFIC_VAR"

Using Variables in Job Definitions:

deploy:
  script:
    - deploy.sh
  environment:
    name: production
    url: https://$DOMAIN_NAME

Security Best Practices for CI/CD Variables

Managing CI/CD variables securely is critical, especially when handling sensitive data. Here are some best practices:

• Use Protected Variables for Sensitive Data: Ensure that variables containing sensitive information are marked as protected to restrict their usage to protected branches and tags.
• Mask Sensitive Variables: Masking hides variable values in job logs, reducing the risk of accidental exposure.
• Avoid Hardcoding Sensitive Information: Always use CI/CD variables for credentials and sensitive data instead of hardcoding them in your scripts.
• Review and Rotate Variables Regularly: Regularly review your CI/CD variables and rotate sensitive ones like API keys and passwords to maintain security.

Common Use Cases for GitLab CI/CD Variables

• Environment Configuration: Use variables to set environment-specific configurations like database URLs, API endpoints, or feature toggles.
• Managing Secrets: Store secrets such as API keys, tokens, and passwords securely using masked and protected variables.
• Dynamic Pipeline Configuration: Use variables to enable or disable certain pipeline features, toggle debugging modes, or specify build parameters.
• Deployment URLs: Define deployment URLs and other deployment-specific configurations dynamically using environment variables.

Debugging and Troubleshooting CI/CD Variables

If you encounter issues with CI/CD variables, consider the following troubleshooting steps:

• Check Variable Scope: Ensure that variables are defined at the correct scope (global, job-specific, or environment-specific).
• Inspect Job Logs: Review job logs to verify variable values, especially if variables are masked or protected.
• Use the printenv Command: Add printenv to your job scripts to list all environment variables available during job execution.