Generate Microcks OpenAPI Examples

Generate realistic, schema-compliant OpenAPI examples (request/response pairs) for Microcks mocks. All examples must be concrete and directly usable—no placeholders or generic values.

When to Use

Use when:

• Building mock APIs with Microcks using realistic request/response examples
• Creating test data that matches real-world API behavior (not generic placeholders)
• Setting up multiple response scenarios for API testing (happy path, errors, edge cases)
• Configuring smart request routing (dispatching) based on request content
• Migrating from live APIs to mock endpoints while maintaining realistic behavior
• Creating reproducible test fixtures with concrete data

Don’t use when:

• Modifying the OpenAPI contract file itself (examples go in separate metadata files)
• Creating mock data without an OpenAPI schema as source of truth
• Using generic/placeholder values (defeats purpose of realistic mocking)
• Static mock responses without routing logic

Core Pattern

1. Start with OpenAPI contract (what API operations exist?)
2. Design realistic scenarios (happy path, errors, edge cases)
3. Create request/response example pairs (concrete data, no placeholders)
4. Define smart routing rules (which scenario matches which request?)
5. Deploy both example data + routing rules to Microcks

Quick Reference

Implementation Steps

Step 1: Understand Your API from OpenAPI Contract

Before generating examples, gather:

1. All operations (GET /users, POST /users, etc.)
2. Request structure (required fields, data types, enums)
3. Response structure (status codes, body schema)
4. Which requests should match which responses (routing logic)

Step 2: Design Realistic Scenarios

For each operation, create 3-5 meaningful examples:

• Happy path: Valid request → success response (200, 201, etc.)
• Error case: Invalid request → error response (400, 401, 404, etc.)
• Edge cases: Boundary values, large arrays, null fields, etc.

Key: Use CONCRETE data from real-world usage, not templates like <email>, {placeholder}.

Step 3: Create APIExamples File

Create a file named <contract-name>.apiexamples.yaml:

apiVersion: mocks.microcks.io/v1alpha1
kind: APIExamples
metadata:
  name: <Same as OpenAPI contract name>
  version: <Same version as OpenAPI contract>
operations:
  <HTTP METHOD> <operation path>:
    <Example Name 1>:
      request:
        headers:
          Content-Type: application/json
        body: |-
          { "concrete": "value" }
      response:
        status: 200
        body: |-
          { "concrete": "response value" }
    <Example Name 2>:
      request:
        headers:
          Content-Type: application/json
        body: |-
          { "concrete": "different value" }
      response:
        status: 200
        body: |-
          { "concrete": "different response" }

CRITICAL RULES:

• No placeholders: All values must be concrete and realistic (not {{ placeholder }}, ..., or <TBD>)
• Match schema: Every example field must comply with OpenAPI schema types, enums, required fields, and constraints
• Example names are identifiers: Names like BEST_CITY, DEFAULT_CITY, INVALID_INPUT are referenced by dispatcher rules
• YAML format strict: Use |- for multi-line strings; validate syntax with yamllint

Step 4: Configure Smart Routing

Create a separate file named <contract-name>.apimetadata.yaml to define dispatcher rules that route requests to the correct example.

For JSON_BODY dispatcher (simple field matching):

operations:
  <HTTP METHOD> <operation path>:
    dispatcher: JSON_BODY
    dispatcherRules: |
      {
        "exp": "/fieldName",
        "op": "equals",
        "cases": {
          "value1": "EXAMPLE_NAME_1",
          "value2": "EXAMPLE_NAME_2",
          "default": "DEFAULT_EXAMPLE"
        }
      }

For JS SCRIPT dispatcher (complex multi-field logic, recommended):

operations:
  <HTTP METHOD> <operation path>:
    dispatcher: JS
    dispatcherRules: |
      const req = JSON.parse(mockRequest.getRequestContent());
      if (req.field1 === "value1" && req.field2 > 10) {
        return "EXAMPLE_NAME_1";
      }
      return "DEFAULT_EXAMPLE";

To use GROOVY dispatcher (legacy or if explicitly needed):

operations:
  <HTTP METHOD> <operation path>:
    dispatcher: GROOVY
    dispatcherRules: |
      import java.util.regex.*;
      def jsonSlurper = new groovy.json.JsonSlurper();
      def req = jsonSlurper.parseText(mockRequest.getRequestContent());
      
      if (req.field1 == "value1" && req.field2 > 10) {
        return "EXAMPLE_NAME_1"
      }
      return "DEFAULT_EXAMPLE"

For complete dispatcher reference, syntax details, and operators, see references/dispatchers-reference.md.

Step 5: Validate and Deploy

1. Syntax check: Validate all YAML files with yamllint or online validator
2. Schema compliance: Ensure every field matches OpenAPI schema (type, enum, required, etc.)
3. Dispatcher mapping: Verify every example name in APIExamples appears in dispatcher cases
4. Consistency: Example names must be identical across APIExamples and APIMetadata
5. Deploy: Upload both .apiexamples.yaml and .apimetadata.yaml files to Microcks

Common Mistakes

Mistake 1: Placeholder Values in Examples

# ❌ BAD: Placeholder value
response:
  body: |-
    { "city": "<city-name>", "rating": 5 }

# ✅ GOOD: Concrete value
response:
  body: |-
    { "city": "Paris", "rating": 8 }

Why? Microcks returns examples as-is. Users expect real data, not templates.

Mistake 2: Dispatcher Cases Don’t Match Example Names

# ❌ BAD: Dispatcher references "BEST", but example is named "BEST_CITY"
cases:
  "Dunkirk": "BEST"

# ✅ GOOD:
cases:
  "Dunkirk": "BEST_CITY"

Microcks fails silently or returns wrong example.

Mistake 3: JSON Pointer Path Incorrect

# ❌ BAD: Path doesn't match request structure
"exp": "/user_city"  # But request is { "city": "Paris" }

# ✅ GOOD:
"exp": "/city"

Mistake 4: Missing Default Case

# ❌ BAD: No default, Microcks returns 404 for unknown requests
"cases": {
  "Paris": "GOOD_CITY",
  "Dunkirk": "BEST_CITY"
}

# ✅ GOOD: Always include default
"cases": {
  "Paris": "GOOD_CITY",
  "Dunkirk": "BEST_CITY",
  "default": "DEFAULT_CITY"
}

Mistake 5: Mixing YAML and JSON Syntax

# ❌ BAD: Invalid YAML (unquoted colons, inconsistent quotes)
body: |-
  { "key": value }  # Missing quotes around value

# ✅ GOOD: Valid JSON within YAML
body: |-
  { "key": "value" }

Red Flags: Avoid These Rationalization Traps

❌ “Templates are faster than concrete data”

Wrong. Microcks returns examples AS-IS. If you use <email> instead of alice@example.com, users receive the literal placeholder in their tests.

Reality: Concrete data takes same time to write and is immediately usable.

❌ “Keep Groovy for consistency with our other dispatchers”

Wrong. Dispatcher choice should be based on requirement complexity, not on sunk cost.

Decision matrix:

• Simple field routing? Use JSON_BODY (even if you have 10 Groovy dispatchers elsewhere)
• Complex multi-field logic? Use JS (modern, recommended for Microcks 1.13+)
• Existing Groovy codebase? Only if explicitly required or migrating legacy

Reality: “Consistency” that keeps you on a worse technology is technical debt, not architecture.

❌ “One example is good enough”

Wrong. One example ≠ realistic mocking. Microcks routes requests based on dispatcher rules. One example = one scenario.

Need minimum 3:

• Happy path (200, 201)
• Error case (400, 401, 404, etc.)
• Edge case (boundary values, empty arrays, etc.)

❌ “I’ll add dispatching rules later”

Wrong. Without dispatcher rules, all requests hit the first example. Your mock isn’t mocking—it’s static.

Reality: APIExamples + APIMetadata (dispatcher rules) are equally critical. Both must exist before testing.

Examples

For real-world, copy-paste-ready examples covering:

• Cities API with JSON_BODY dispatcher (recommended starting point)
• Authorization API with JavaScript SCRIPT dispatcher (recommended for complex logic)
• Orders API with Groovy SCRIPT dispatcher (legacy, optional)

See examples/README.md for index and quick navigation.

Key Constraints

• Never edit OpenAPI contract: Examples go in separate .apiexamples.yaml only
• Concrete values only: No {{ }}, <>, placeholders, or generic values
• Schema compliance: All examples must validate against OpenAPI schema
• Names must match: Example names in APIExamples must appear in dispatcher cases
• YAML validation: Strict YAML syntax; indent consistently (2 spaces)
• JSON format: Request/response bodies must be valid JSON; use |- for multi-line

Resources

• Microcks Dispatching Documentation
• references/dispatchers-reference.md — Complete reference for JSON_BODY, Groovy SCRIPT, JavaScript SCRIPT
• examples/README.md — Real-world usage examples with index
• YAML Validator: yamllint, Online YAML Validator
• JSON Validator: jsonlint