OpenAPI Generator Project — Build a Complete Code Generation System

# Complete project directory structure:
# api-codegen-system/
#   specs/
#     v1/
#       openapi.yaml
#       changelog.md
#     v2/
#       openapi.yaml
#       changelog.md
#     latest -> v2
#   codegen/
#     python-fastapi.yaml
#     typescript-fetch.yaml
#     swift5.yaml
#     kotlin.yaml
#     html-docs.yaml
#   templates/
#     custom/
#       controller.mustache
#       model.mustache
#   scripts/
#     validate.sh
#     generate-all.sh
#     test-generated.sh
#     publish-sdks.sh
#     generate-changelog.py
#     bump-version.py
#   .github/
#     workflows/
#       codegen.yml
#   output/
#     .gitkeep

echo "Project structure created"
# Expected output:
# Project structure created

# specs/v2/openapi.yaml
openapi: 3.0.3
info:
  title: Orders API
  description: |
    Orders API for managing customer orders.
    Used by DodaTech's e-commerce platform.
  version: 2.0.0
  contact:
    name: API Team
    email: api@dodatech.com
servers:
  - url: https://api.dodatech.com/v2
    description: Production
paths:
  /orders:
    get:
      operationId: listOrders
      summary: List customer orders
      parameters:
        - name: limit
          in: query
          schema:
            type: integer
            maximum: 100
            default: 20
        - name: status
          in: query
          schema:
            type: string
            enum: [pending, confirmed, shipped, delivered]
      responses:
        '200':
          description: Order list
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/Order'
    post:
      operationId: createOrder
      summary: Create a new order
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CreateOrderRequest'
      responses:
        '201':
          description: Order created
          headers:
            Location:
              schema:
                type: string
components:
  schemas:
    Order:
      type: object
      required: [id, customer_id, items, total]
      properties:
        id:
          type: string
          format: uuid
        customer_id:
          type: string
        items:
          type: array
          items:
            $ref: '#/components/schemas/OrderItem'
        total:
          type: number
        status:
          type: string
          enum: [pending, confirmed, shipped, delivered]
    OrderItem:
      type: object
      properties:
        product_id:
          type: string
        quantity:
          type: integer
    CreateOrderRequest:
      type: object
      required: [customer_id, items]
      properties:
        customer_id:
          type: string
        items:
          type: array
          items:
            $ref: '#/components/schemas/OrderItem'

# scripts/generate-all.sh
# !/bin/bash
set -euo pipefail

SPEC_VERSION="${1:-v2}"
SPEC_FILE="specs/$SPEC_VERSION/openapi.yaml"
OUTPUT_DIR="output/$SPEC_VERSION"

echo "=== Generating all SDKs for $SPEC_VERSION ==="

# Validate spec first
echo "Validating spec..."
openapi-generator validate -i "$SPEC_FILE"
if [ $? -ne 0 ]; then
    echo "Spec validation failed!"
    exit 1
fi

# Define generators and configs
declare -A GENERATORS
GENERATORS["python-fastapi"]="codegen/python-fastapi.yaml"
GENERATORS["typescript-fetch"]="codegen/typescript-fetch.yaml"
GENERATORS["swift5"]="codegen/swift5.yaml"
GENERATORS["kotlin"]="codegen/kotlin.yaml"
GENERATORS["html"]="codegen/html-docs.yaml"

# Generate each SDK
for gen in "${!GENERATORS[@]}"; do
    config="${GENERATORS[$gen]}"
    echo "Generating $gen..."

    mkdir -p "$OUTPUT_DIR/$gen"
    openapi-generator generate \
        -i "$SPEC_FILE" \
        -g "$gen" \
        -o "$OUTPUT_DIR/$gen" \
        -c "$config"

    if [ $? -eq 0 ]; then
        echo "  $gen generated successfully"
    else
        echo "  $gen generation failed!"
        exit 1
    fi
done

echo "=== Generation complete ==="

# .github/workflows/codegen.yml
name: API Code Generation System
on:
  push:
    branches: [main]
    paths:
      - 'specs/**'
  pull_request:
    paths:
      - 'specs/**'

jobs:
  validate-and-generate:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with:
          distribution: 'temurin'
          java-version: '17'

      - name: Validate spec
        run: |
          SPEC=$(readlink -f specs/latest)
          openapi-generator validate -i $SPEC/openapi.yaml

      - name: Generate all SDKs
        run: |
          bash scripts/generate-all.sh $(basename $(readlink -f specs/latest))

      - name: Test generated code
        run: |
          bash scripts/test-generated.sh

      - name: Generate changelog
        if: github.ref == 'refs/heads/main'
        run: |
          # Compare with previous version
          PREV=$(ls -d specs/v* | sort -V | tail -2 | head -1)
          CURR=$(readlink -f specs/latest)
          python scripts/generate-changelog.py $PREV $CURR

      - name: Publish SDKs
        if: github.ref == 'refs/heads/main'
        run: |
          bash scripts/publish-sdks.sh
        env:
          NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
          PYPI_TOKEN: ${{ secrets.PYPI_TOKEN }}

      - name: Deploy docs
        if: github.ref == 'refs/heads/main'
        run: |
          npx netlify-cli deploy --dir=output/latest/html --prod

# scripts/test-generated.sh
# !/bin/bash
set -euo pipefail

SPEC_VERSION="${1:-v2}"
BASE_DIR="output/$SPEC_VERSION"

echo "=== Testing generated code ==="

# Test Python server
if [ -d "$BASE_DIR/python-fastapi" ]; then
    echo "Testing Python FastAPI..."
    cd "$BASE_DIR/python-fastapi"
    pip install -r requirements.txt -q
    python -m pytest tests/ -v
    cd ../..
    echo "Python tests passed"
fi

# Test TypeScript client
if [ -d "$BASE_DIR/typescript-fetch" ]; then
    echo "Testing TypeScript Fetch..."
    cd "$BASE_DIR/typescript-fetch"
    npm install --silent
    npm test
    cd ../..
    echo "TypeScript tests passed"
fi

# Test Swift client
if [ -d "$BASE_DIR/swift5" ]; then
    echo "Building Swift..."
    cd "$BASE_DIR/swift5"
    swift build 2>/dev/null
    cd ../..
    echo "Swift build passed"
fi

echo "=== All tests passed ==="