Build Ordering

When you run emb resources build, EMB analyzes dependencies and determines the correct build order.

The Dependency Graph

Our microservices project has this dependency structure:

base
 ├── api (depends on base)
 └── worker (depends on base)

gateway (no dependencies)

When you run emb resources build:

1. base builds first (no dependencies)
2. api and worker build after base completes
3. gateway can build at any point (no dependencies)

EMB guarantees dependencies are built before their dependents. The order of independent components (like gateway) is not guaranteed.

Building All Resources

emb resources build

EMB will:

1. Analyze the dependency graph
2. Determine a valid build order
3. Build each component one by one
4. Ensure dependencies complete before dependents

Building a Single Component

When you build a specific component:

emb resources build worker

EMB automatically builds dependencies first:

1. Checks if base:image exists and is up-to-date
2. Builds base:image if needed
3. Then builds worker:image

Dry Run

See what would be built without actually building:

emb resources build --dry-run

This shows the build order and what images would be created.

Circular Dependencies

EMB detects and reports circular dependencies. If you accidentally create:

api/Embfile.yml

resources:
  image:
    dependencies:
      - worker:image

# worker/Embfile.yml
resources:
  image:
    dependencies:
      - api:image

EMB will fail with a clear error message explaining the cycle.

Cache and Rebuilds

EMB tracks when images were last built. It rebuilds when:

• Source files have changed
• A dependency was rebuilt
• You use --force

Summary

You’ve learned about microservices patterns in EMB:

• Base images - Shared foundations for consistency
• Dependencies - Declaring build order requirements
• Build ordering - Automatic resolution of the dependency graph

Next Tutorial

Ready to learn about environment-specific configurations? Continue to Production Ready to explore:

• Multi-stage Docker builds
• Flavors for different environments
• JSON Patch operations