[Generate OpenAPI schema dynamically] #openapi #template #bash #shell

template.sh

#!/bin/bash

AWK_PATH=$(which awk)
CAT_PATH=$(which cat)

read -rp "Enter API Version (e.g. 1.0.0): " VERSION
read -rp "Enter API Title: " TITLE
read -rp "Enter API Description: " DESCRIPTION
read -rp "Enter Your Name (for contact info): " NAME
read -rp "Enter Your Email (for contact info): " EMAIL
read -rp "Enter Category (for DevHub URL, e.g. services, see common/categories.yaml): " CATEGORY
read -rp "Enter Slug (for DevHub URL, e.g. backend): " SLUG
read -rp "Enter API Path (e.g. /service/{service_id}/version/{version_id}/backend): " PATH
read -rp "Enter Resource (e.g. backend): " RESOURCE
read -rp "Enter output file name (e.g. 'backend' will generate a 'backend.yaml' file): " OUTPUT_FILENAME

rm "${OUTPUT_FILENAME}.yaml" 2>/dev/null

# Function to capitalize the first letter of a string
capitalize() {
  echo "$1" | $AWK_PATH '{print toupper(substr($0,1,1)) tolower(substr($0,2))}'
}

# Replace template fields in the template content
content=$( $CAT_PATH <<EOF
openapi: 3.0.3
info:
  version: '$VERSION'
  title: $(capitalize "$TITLE")
  description: $DESCRIPTION.
  termsOfService: https://www.fastly.com/terms
  contact:
    name: $NAME
    email: $EMAIL
    url: https://www.fastly.com

servers:
  - url: https://api.fastly.com

security:
  - token_engineer: []

x-taxonomy:
  category:
    \$ref: 'common/categories.yaml#/$CATEGORY'
  slug: $SLUG

paths:
  $PATH:
    get:
      summary: List $RESOURCE
      description: List all $RESOURCE.
      operationId: list-${RESOURCE}s
      responses:
        '200':
          \$ref: '#/components/responses/response-$RESOURCE'

    post:
      summary: Create a $RESOURCE
      description: Create a $RESOURCE.
      operationId: create-$RESOURCE
      requestBody:
        \$ref: '#/components/requestBodies/requestBody-$RESOURCE'
      responses:
        '200':
          \$ref: '#/components/responses/response-$RESOURCE'

  '$PATH/{${RESOURCE}_id}':
    get:
      summary: Get a $RESOURCE
      description: Get a $RESOURCE.
      operationId: list-$RESOURCE-s-${RESOURCE}_id
      parameters:
        - \$ref: '#/components/parameters/parameter-${RESOURCE}_id'
      responses:
        '200':
          \$ref: '#/components/responses/response-$RESOURCE'

    patch:
      summary: Update a $RESOURCE
      description: Update a $RESOURCE.
      operationId: update-$RESOURCE
      parameters:
        - \$ref: '#/components/parameters/parameter-${RESOURCE}_id'
      requestBody:
        \$ref: '#/components/requestBodies/requestBody-$RESOURCE'
      responses:
        '200':
          \$ref: '#/components/responses/response-$RESOURCE'

    delete:
      summary: Delete a $RESOURCE
      description: Delete a $RESOURCE.
      operationId: delete-$RESOURCE
      parameters:
        - name: ${RESOURCE}_id
          in: path
          required: true
          schema:
            type: string
            description: $(capitalize "$RESOURCE") Identifier (UUID).
      responses:
        '200':
          description: OK

components:
  examples:
    example-requestBody-$RESOURCE:
      value:
        example_field_name_1: '...'
        example_field_name_2:
          - id: '...'
            title: '...'
            example_of_nullable_field: null

    example-response-$RESOURCE:
      value:
        example_field_name_1: '...'
        example_field_name_2:
          - id: '...'
            title: '...'
            example_of_nullable_field: null

  parameters:
    parameter-${RESOURCE}_id:
      name: ${RESOURCE}_id
      in: path
      required: true
      schema:
        type: string
        description: $(capitalize "$RESOURCE") Identifier (UUID).

  requestBodies:
    requestBody-$RESOURCE:
      content:
        application/json:
          schema:
            \$ref: '#/components/schemas/schema-requestBody-$RESOURCE'
          examples:
            body:
              \$ref: '#/components/examples/example-requestBody-$RESOURCE'

  responses:
    response-$RESOURCE:
      description: Example response.
      content:
        application/json:
          schema:
            \$ref: '#/components/schemas/schema-response-$RESOURCE'
          examples:
            body:
              \$ref: '#/components/examples/example-response-$RESOURCE'

  securitySchemes:
    token_engineer:
      \$ref: 'common/security.yaml#/token_engineer'

  schemas:
    schema-requestBody-$RESOURCE:
      title: $RESOURCE
      description: A $RESOURCE request body.
      allOf:
        - \$ref: '#/components/schemas/schema-${RESOURCE}-mulitple-schemas-example-1'
        - \$ref: '#/components/schemas/schema-${RESOURCE}-mulitple-schemas-example-2'

    schema-response-$RESOURCE:
      title: $RESOURCE
      description: A $RESOURCE response.
      allOf:
        - \$ref: '#/components/schemas/schema-${RESOURCE}-mulitple-schemas-example-1'
        - \$ref: '#/components/schemas/schema-${RESOURCE}-mulitple-schemas-example-2'

    schema-${RESOURCE}-mulitple-schemas-example-1:
      type: object
      properties:
        example_field_name_1:
          type: string
          description: Some example description.

    schema-${RESOURCE}-mulitple-schemas-example-2:
      type: object
      properties:
        example_field_name_2:
          type: array
          items:
            \$ref: '#/components/schemas/schema-array-items-as-object'

    schema-array-items-as-object:
      type: object
      title: Example array item
      description: An example array item.
      properties:
        id:
          type: string
          description: An example identifier (UUID).
          readOnly: true
        title:
          type: string
        example_of_nullable_field:
          type: string
          nullable: true
          default: null
          description: A field that can be null.
      required:
        - title
EOF
)

# Write the final output to a new yaml file
echo "$content" > "${OUTPUT_FILENAME}.yaml"
echo ""
echo "Script executed successfully. Output saved to ${OUTPUT_FILENAME}.yaml"