Resolvers in Pipeline

Resolvers are the third step in the template generation pipeline, after processors but before plugins.

Pipeline Overview

Execution Order

1. Template Execution

• Template collects user input
• Template defines files and configuration
• Template specifies processors, resolvers, and plugins

2. Processor Execution

• Processors transform individual files
• Applied to all files matching globs
• Outputs transformed files

3. Resolver Execution

This is where resolvers run.

• Receives multiple versions of conflicting files
• Applies merge logic based on configuration
• Outputs single merged file per conflict

4. Plugin Execution

• Runs after all files are generated
• Can run commands, modify files
• Returns final directory

When Resolvers Execute

Resolvers execute when:

• Multiple templates provide the same file path
• Template composition creates file overlaps
• Explicit resolver configuration in cyan.yaml

Resolver Configuration

Templates configure resolvers in cyan.yaml:

resolvers:
  - resolver: org/json-merger:1
    config:
      arrayStrategy: concat
      deepMerge: true
    files:
      - config.json
      - package.json
      - "*.json"

Configuration Options

Data Flow

Input to Resolver

{
  "config": {
    "arrayStrategy": "concat"
  },
  "files": [
    {
      "path": "config.json",
      "content": "{\"name\": \"app\"}",
      "origin": {
        "template": "base-template",
        "layer": 0
      }
    },
    {
      "path": "config.json",
      "content": "{\"version\": \"1.0\"}",
      "origin": {
        "template": "feature-template",
        "layer": 1
      }
    }
  ]
}

Output from Resolver

{
  "path": "config.json",
  "content": "{\"name\": \"app\", \"version\": \"1.0\"}"
}

Error Handling

Resolvers should:

• Validate input - Check file paths match
• Handle edge cases - Empty files, missing content
• Report errors - Throw meaningful exceptions

Common Errors

Performance Considerations

• File size - Large files may need streaming
• Memory usage - Be mindful of memory when merging many files
• Timeout - Complex merges may need more time

Next Steps