How should the various services s...

In a microservices architecture, sharing a common database schema and code among various services can be challenging due to the principles of loose coupling and service independence. Here are some best practices and approaches to address this issue:

Sharing Common Code

1. Packaging Systems:

   • Use a packaging system appropriate for your programming language (e.g., Maven for Java, PyPI for Python, NPM for Node.js). This allows you to create reusable libraries that can be versioned and managed independently[1][5][16].
   • Publish these libraries to a private repository or artifact repository, and include them as dependencies in your microservices.

2. Monorepo Approach:

   • Maintain all microservices in a single repository with a multi-module project setup. This can simplify dependency management but may introduce some coupling[1][16].

3. Git Submodules/Subtrees:

   • Use Git submodules or subtrees to include shared code in multiple repositories. This approach allows you to keep shared code in a separate repository while including it in the microservices that need it[1][16].

4. Avoiding Code Sharing:

   • In some cases, it might be better to avoid sharing code altogether to maintain the independence of microservices. This can prevent issues related to versioning and dependencies[1][14].

Sharing a Common Database Schema

1. Database per Service:

   • The recommended approach is to have each microservice manage its own database schema. This ensures loose coupling and allows each service to evolve independently[1][4][10][13].
   • Each microservice should only access its own database, and data sharing between services should be done via APIs[1][4][13].

2. Shared Database with Schema per Service:

   • If a shared database is necessary, use separate schemas for each microservice within the same database. This maintains some level of isolation while allowing shared access to the database[4][12][18].
   • Ensure that schema changes are backward-compatible to avoid breaking other services[7][9].

3. Shared Database with Private Tables:

   • Another approach is to have private tables for each service within a shared database. This can help in maintaining data isolation while using a common database infrastructure[4][18].

4. Shared Database with Careful Management:

   • If using a shared database, manage it carefully to avoid issues like schema changes affecting multiple services. Use database transactions to ensure data consistency and avoid runtime coupling[6][7][17].

Considerations

• Trade-offs:
  • Using a shared database can simplify data management but ...