How are progressive delivery workflows managed in trunk-based deployments?

Trunk-based development emphasizes frequently merging code into the main branch, creating the challenge of managing unfinished features without disrupting a releasable main branch. Progressive delivery workflows, utilizing feature flags, address this by separating code deployment from feature release, allowing code to be deployed to production while keeping features hidden until ready. This approach maintains a distinction between deployment, a technical operation, and release, a business decision, enabling continuous deployment without premature feature exposure. Progressive rollout strategies, such as percentage-based, segment-based, and canary deployments, limit potential issues by gradually exposing features to users. Feature flag platforms facilitate these processes by offering control over flag configurations and supporting runtime changes without redeployment. Effective progressive delivery relies on observability and automated responses, with monitoring systems tracking flag evaluations and integrating with analytics platforms to assess rollout impacts. Technical patterns ensure consistent user experiences through stickiness and address flag lifecycle management, distinguishing between temporary release flags and operational flags with ongoing utility. This approach, combined with trunk-based development, allows for continuous deployment while maintaining granular control over feature releases and reducing risks associated with new functionalities.