Strangler Fig Pattern

1. Introduction

The Strangler Fig Pattern is an architectural pattern for gradually replacing a legacy system with a new system. The concept is inspired by the strangler fig tree, which grows around a host tree, eventually replacing it without needing to remove it all at once.

2. Key Concepts

• Incremental Migration: Migrate features one at a time instead of a complete rewrite.
• Interoperability: Both systems operate simultaneously during the transition period.
• Testing: Ensure that new implementations are tested before full replacement.

3. Implementation Steps

1. Identify Features: Determine which features of the legacy system need to be replaced.
2. Build New Components: Create new modules or services for the identified features.
3. Integrate: Connect the new components with the existing legacy system.
4. Test: Conduct thorough testing to ensure interoperability.
5. Deploy: Gradually switch users from the legacy system to the new components.
6. Repeat: Continue the process until the legacy system is fully replaced.

                graph TD;
                    A[Start] --> B{Identify Features};
                    B --> C[Build New Components];
                    C --> D[Integrate];
                    D --> E[Test];
                    E --> F[Deploy];
                    F --> G{More Features?};
                    G -->|Yes| B;
                    G -->|No| H[End];
            

4. Best Practices

• Prioritize critical features for migration.
• Document all changes and maintain clear communication with stakeholders.
• Ensure that the new system is scalable and maintainable.
• Monitor performance and gather user feedback throughout the migration.

5. FAQ