Azure Devops

Azure DevOps Pipelines Code Review Rules

Security (Critical)

• Template Expression Safety: Only interpolate variables that have undergone strict validation and escaping in template expressions (${{ }}). Never use direct user input in template expansion to prevent injection attacks during pipeline parsing
• Runtime Variable Safety: Sanitize and validate runtime variables ($()) before using in scripts. Never interpolate untrusted data into script commands to prevent command injection
• Comment Hygiene: Never use HTML comments (<!-- -->) in pipeline YAML files. Use standard YAML comments (#) only
• Use service connections with minimal permissions
• Store secrets in Variable Groups linked to Key Vault
• Use secure files for certificates/keys
• Enable branch policies for protected branches
• Require approvals for production environments
• Scan pipeline YAML for hardcoded secrets/credentials
• Review inline scripts for command injection, unsafe variable expansion, and commonly exploited patterns
• Consider using static analysis tools for script security
• Avoid echoing secrets in script output
• Use credential scanning tools in PR validation

Variables

• Explicitly declare all variables with restricted scope
• Review Variable Group linking permissions to prevent unauthorized access
• Use Variable Groups for shared configuration
• Mark sensitive variables as secret (masked in logs)
• Use template expressions ${{ }} for compile-time, $() for runtime
• Don't hardcode environment-specific values
• Follow naming conventions: use camelCase or UPPER_SNAKE_CASE
• Name Variable Groups clearly (e.g., prod-app-config)
• Understand variable override precedence (job > stage > root > variable group); see docs for advanced patterns
• Document variable purpose in Variable Group descriptions

Task Management (Essential)

• Pin task versions (task@2 not task)
• Use built-in tasks over script when available
• Explicitly specify agent pool (pool: vmImage or pool: name)
• Review custom scripts for embedded secrets or insecure code
• Avoid inline scripts for complex logic (use script files)
• Set continueOnError only when intentional
• Use condition for conditional execution
• Set task timeouts to prevent hanging jobs

Stages and Jobs

• Use stages for environment progression (dev -> staging -> prod)
• Use deployment jobs for environment deployments
• Define explicit dependsOn for job ordering
• Use parallel jobs where independent
• Follow naming conventions: use descriptive stage/job names
• Set resource limits (pool.demands) when needed
• Configure concurrency limits for deployment jobs
• Use meaningful displayName for stages and jobs

Environments

• Create environments for each deployment target
• Configure approvals and checks on environments
• Use environment variables for environment-specific config
• Track deployments in environment history

Templates

• Extract reusable steps into templates
• Use parameters for template customization
• Store templates in a shared repository
• Version template references
• Document template purpose and parameters
• Validate template compatibility before use
• Handle template inclusion errors gracefully
• Test template changes before merging
• For complex parameter overrides, see Azure DevOps Template Documentation

Best Practices