Mocker — Multi-Server Routing¶

TL;DR — One mocker binary, multiple logical servers on different ports; each server owns its stubs and exposes a deterministic channel name so multiple runners can target specific servers without cross-talk.

When to use¶

Your system-under-test calls several downstream services that you want to mock independently in one process.
You want each mock to have its own response shape, latency, and failure mode without spinning up three containers.
You need a worked example of the Servers (plural) YAML root and the channel-name convention.

YAML configuration¶

DataSources:
  - Name: OrderResponses
    Generator: FromFileSystem
    GeneratorConfiguration:
      DataArrangeOrder: AsciiAsc
      FileSystem: { Path: Fixtures/orders }
  - Name: PaymentResponses
    Generator: FromFileSystem
    GeneratorConfiguration:
      DataArrangeOrder: AsciiAsc
      FileSystem: { Path: Fixtures/payments }
  - Name: CatalogResponses
    Generator: FromFileSystem
    GeneratorConfiguration:
      DataArrangeOrder: AsciiAsc
      FileSystem: { Path: Fixtures/catalog }

Stubs:
  - Name: OrdersStub
    Processor: DataSourceResponse
    DataSourceNames: [OrderResponses]
    ProcessorConfiguration: { StatusCode: 200 }
  - Name: PaymentsStub
    Processor: DataSourceResponse
    DataSourceNames: [PaymentResponses]
    ProcessorConfiguration: { StatusCode: 200 }
  - Name: CatalogStub
    Processor: DataSourceResponse
    DataSourceNames: [CatalogResponses]
    ProcessorConfiguration: { StatusCode: 200 }

Servers:
  - Name: orders
    InstanceName: primary
    Http:
      Port: 8081
      IsLocalhost: false
      Endpoints:
        - Path: /orders/{id}
          Actions:
            - { Name: GetOrder,    Method: Get,  TransactionStubName: OrdersStub }
        - Path: /orders
          Actions:
            - { Name: CreateOrder, Method: Post, TransactionStubName: OrdersStub }

  - Name: payments
    InstanceName: primary
    Http:
      Port: 8082
      IsLocalhost: false
      Endpoints:
        - Path: /payments
          Actions:
            - { Name: Charge, Method: Post, TransactionStubName: PaymentsStub }

  - Name: catalog
    InstanceName: primary
    Http:
      Port: 8083
      IsLocalhost: false
      Endpoints:
        - Path: /catalog/{sku}
          Actions:
            - { Name: GetItem, Method: Get, TransactionStubName: CatalogStub }

C# (CAC) usage¶

No custom processor is required for pure routing. The mocker is fully YAML-driven once Bootstrap runs:

QaaS.Mocker.Bootstrap.New(args).Run();

Add custom processors per stub when you need behaviour beyond DataSourceResponse — see Processors — custom authoring guide.

Minimal example¶

A single server with one endpoint, copied from one fixture file:

DataSources:
  - Name: OrderResponses
    Generator: FromFileSystem
    GeneratorConfiguration:
      DataArrangeOrder: AsciiAsc
      FileSystem: { Path: Fixtures/orders }
Stubs:
  - Name: OrdersStub
    Processor: DataSourceResponse
    DataSourceNames: [OrderResponses]
    ProcessorConfiguration: { StatusCode: 200 }
Servers:
  - Name: orders
    InstanceName: primary
    Http:
      Port: 8081
      IsLocalhost: false
      Endpoints:
        - Path: /orders
          Actions:
            - { Name: CreateOrder, Method: Post, TransactionStubName: OrdersStub }

Realistic example¶

Two instances of the same logical server (blue/green) on different ports, so runners can deliberately split traffic to test cutovers:

Servers:
  - Name: orders
    InstanceName: blue
    Http: { Port: 8081, IsLocalhost: false, Endpoints: [ ] }   # blue stubs here
  - Name: orders
    InstanceName: green
    Http: { Port: 8181, IsLocalhost: false, Endpoints: [ ] }   # green stubs here

Runner A points at http://localhost:8081 (instance blue); Runner B points at :8181 (instance green). Both can run in parallel against the same mocker process without cross-contamination.

Edge cases¶

Server: (singular) and Servers: (plural) are mutually exclusive. Use plural the moment you need more than one.
Ports must be unique across Servers[*].Http.Port; the mocker fails fast at startup if not.
Name is required when there is more than one server; the runner uses it to disambiguate channels.
InstanceName defaults to a deterministic value when omitted, but pinning it explicitly makes channel names predictable in CI logs.
IsLocalhost: false binds to 0.0.0.0 (reachable from sibling containers). Set true for laptop dev to stay on 127.0.0.1.