Chef Agent

Location: src/inputs/chef.py

The Chef Agent analyzes Chef cookbooks, recipes, templates, and attributes to create migration specifications for converting Chef infrastructure to Ansible.

Workflow 

stateDiagram-v2
    [*] --> FetchDependencies
    FetchDependencies --> WriteReport
    WriteReport --> CheckFiles
    CheckFiles --> CleanupSpec
    CleanupSpec --> [*]

    note right of FetchDependencies
        Resolves external cookbooks
        from Chef Supermarket using
        Berksfile
    end note

    note right of WriteReport
        Analyzes recipes, templates,
        attributes using Tree-sitter
        and LLM
    end note

    note right of CheckFiles
        Validates each file mapping
        with AI-powered review
    end note

    note right of CleanupSpec
        Refines and finalizes
        migration specification
    end note

Stage 1: Fetch Dependencies

Goal: Resolve and download external cookbook dependencies

# Executed internally by agent
berks install
berks vendor /tmp/cookbooks

Process:

  1. Read Berksfile or metadata.rb
  2. Download dependencies from Chef Supermarket
  3. Cache in temporary directory
  4. Make available for analysis

Tools Used:

  • Chef Workstation CLI (berks)
  • File system operations

Stage 2: Write Report

Goal: Generate initial migration specification using code analysis

Process:

flowchart TB
    Start[Start Analysis] --> List[List All Files]
    List --> Filter{File Type?}

    Filter -->|Recipe .rb| ParseRuby[Tree-sitter Parse]
    Filter -->|Template .erb| AnalyzeTemplate[Extract Variables]
    Filter -->|Attribute .rb| ParseAttributes[Extract Defaults]
    Filter -->|Other| Skip[Document Only]

    ParseRuby --> AIAnalysis[AI Analysis]
    AnalyzeTemplate --> AIAnalysis
    ParseAttributes --> AIAnalysis

    AIAnalysis --> Mapping[Generate Resource Mapping]
    Mapping --> Spec[Initial Specification]

    style ParseRuby fill:#e8f5e9
    style AIAnalysis fill:#e3f2fd
    style Spec fill:#fff3e0

Tools Used:

  • Tree-sitter: Ruby AST parsing
  • LangChain LLM: Semantic analysis
  • File operations: Read recipes, templates, attributes

Example Analysis:

Input (Chef recipe):

package 'nginx' do
  action :install
end

template '/etc/nginx/nginx.conf' do
  source 'nginx.conf.erb'
  variables(
    worker_processes: node['nginx']['workers'],
    worker_connections: node['nginx']['connections']
  )
  notifies :reload, 'service[nginx]'
end

service 'nginx' do
  action [:enable, :start]
end

Output (Specification excerpt):

## Resource Mapping

| Chef Resource | Ansible Module | Notes |
|---------------|----------------|-------|
| package 'nginx' | package: name=nginx state=present | Direct mapping |
| template | template: src=nginx.conf.j2 dest=/etc/nginx/nginx.conf | ERB→Jinja2, extract variables |
| service 'nginx' | service: name=nginx state=started enabled=yes | Direct mapping |

## Variables

| Chef Attribute | Ansible Variable | Default |
|----------------|------------------|---------|
| node['nginx']['workers'] | nginx_worker_processes | auto |
| node['nginx']['connections'] | nginx_worker_connections | 1024 |

## Handlers

| Chef Notification | Ansible Handler | Trigger |
|-------------------|-----------------|---------|
| notifies :reload, 'service[nginx]' | Reload nginx | Template change |

Stage 3: Check Files

Goal: Validate each file mapping for correctness

Process:

sequenceDiagram
    participant Agent
    participant LLM
    participant TreeSitter
    participant Spec

    loop For each file in cookbook
        Agent->>TreeSitter: Parse file
        TreeSitter-->>Agent: AST
        Agent->>LLM: Review mapping for this file
        LLM-->>Agent: Validation result
        Agent->>Spec: Update/refine mapping
    end

    Agent->>Spec: Mark validation complete

Validation Checks:

  • All resources have Ansible equivalents
  • Variables correctly extracted
  • Dependencies properly identified
  • Edge cases documented

Stage 4: Cleanup Specification

Goal: Finalize and refine the migration specification

Process:

  • Remove redundant entries
  • Organize by logical sections
  • Add implementation notes
  • Flag complex conversions

Output: migration-plan-<cookbook-name>.md

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