CLI Architecture

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CLI Architecture

Overview

The AsyncAPI CLI is built with oclif and provides both command-line operations and a REST API server for working with AsyncAPI specifications.


Architecture Diagram

1┌─────────────────────────────────────────────────┐
2  Entry Points                                   
3  ┌──────────┐              ┌──────────┐         
4     CLI                     API             
5    (oclif)                (Express)│         
6  └────┬─────┘              └────┬─────┘         
7└───────┼─────────────────────────┼───────────────┘
8        └───────────┬─────────────┘
9                    
10        ┌───────────────────────┐
11           Domain Services     
12          Validation, Generator│
13          Convert, Config      
14        └───────────┬───────────┘
15                    
16        ┌───────────────────────┐
17           Domain Models       
18          Specification,Context│
19        └───────────┬───────────┘
20                    
21        ┌───────────────────────┐
22           Utilities           
23          Logger, Helpers      
24        └───────────────────────┘

Directory Structure

1src/
2├── apps/
3   ├── cli/              # CLI commands & internals
4   └── api/              # REST API (Express)
5├── domains/
6   ├── models/           # Specification, Context
7   └── services/         # Business logic
8├── errors/               # Custom errors
9├── interfaces/           # TypeScript types
10└── utils/                # Utilities

Core Components

CLI Application

ComponentDescription
Entry Pointsbin/run (dev), bin/run_bin (prod)
Base CommandMetrics, parser integration, error handling

Commands:

  • Core: validate, convert, format, optimize, diff, bundle
  • Generation: generate client, generate models, generate fromTemplate
  • Config: config context, config analytics, config versions
  • Utility: new file, new template, start api|studio|preview, pretty

API Server

Endpoints: /v1/validate, /v1/parse, /v1/generate, /v1/convert, /v1/bundle, /v1/diff, /v1/docs, /v1/help, /v1/version

Features: Express with Helmet security, CORS, compression, RFC 7807 error responses

Domain Services

All services extend BaseService and return ServiceResult<T>:

ServicePurpose
ValidationServiceValidates specs with Spectral, calculates scores
GeneratorServiceGenerates code/models
ConvertServiceConverts between AsyncAPI/OpenAPI formats
ConfigServiceManages CLI config and contexts
ArchiverServiceCreates ZIP archives

Domain Models

ModelPurpose
SpecificationLoads from file, URL, or context; auto-detects asyncapi.json|yml|yaml
ContextManages multiple AsyncAPI contexts; stored in ~/.asyncapi/

Error Classes

ContextError, SpecificationFileError, ValidationError, GeneratorError, DiffError


Execution Flow

CLI Command:

User Command  oclif  Base Command  Domain Service  ServiceResult

API Request:

HTTP Request  Express  Controller  Domain Service  HTTP Response

Extension Points

AddSteps
New CommandCreate in src/apps/cli/commands/, extend Command, implement run()
New API EndpointCreate controller in src/apps/api/controllers/, register in index.ts
New ServiceCreate in src/domains/services/, extend BaseService, return ServiceResult<T>

Configuration

ConfigLocation
CLI Context~/.asyncapi/contexts.json, ~/.asyncapi/.current
Analytics~/.asyncapi-analytics

Environment Variables:

  • NODE_ENVdevelopment | production | test
  • PORT — API server port (default: 3000)
  • ASYNCAPI_METRICS_* — Metrics configuration

Technology Stack

CategoryTechnologies
Coreoclif, TypeScript, Express
AsyncAPI@asyncapi/parser, generator, converter, bundler, diff, optimizer
Supportingwinston, ajv, chalk, @clack/prompts
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