author-mocker-yaml

When to use

Use when you must produce a .mocker.yaml that boots a QaaS.Mocker HTTP server with at least one stub.

Steps

1. Servers block

Servers:
  - Http:
      Port: 8080           # unique across all servers; duplicates = fail-fast (FB s03)
      # IsLocalhost: false  # omit or false → binds 0.0.0.0; true → 127.0.0.1 only (BAD in Docker)
      Endpoints:
        - Path: /hello      # Path on Mocker side HAS the leading slash (FB s03). ALL-LOWERCASE — mocker lowercases this but matches the request case-sensitively (FB s13#5b)
          Actions:
            - Name: HelloOk
              Method: Get   # Get|Post|Put|Delete|Head|Options|Patch|Trace|Connect (FB s03)
              TransactionStubName: HelloStub

• Path on Endpoints uses a leading slash; Route in runner YAML does NOT (FB s13#5).
• Routes must be all-lowercase on BOTH the mocker Path: and the runner Route: — the mocker lowercases the configured Path then matches the request path case-sensitively, so Path: /myRoute + Route: myRoute → 404 (FB s13#5b).
• Each endpoint Action links to a Stub via TransactionStubName.

2. Stubs block

Stubs:
  - Name: HelloStub
    Processor: StaticResponseProcessor   # simple class name (FB s03)
    ProcessorConfiguration:              # NEVER TransactionData (FB s13#1)
      Body: hello
      StatusCode: 200
      ContentType: "text/plain; charset=utf-8"

• ProcessorConfiguration is the only correct key. Using TransactionData produces: Property TransactionData in path Stubs:0 - not found in TransactionStubConfig object (FB s13#1).
• 9 built-in processors ship in QaaS.Common.Processors — see references/processors-summary.md.
• Runtime always adds 2 default stubs (not-found + internal-error): Built 4 transaction stub(s) including default not-found and internal-error stubs (FB s03, LAB L5).

3. DataSources block (optional, needed by DataSourceResponseProcessor)

DataSources:
  - Name: MyData
    Generator: FromFileSystem
    GeneratorConfiguration:
      DataArrangeOrder: AsciiAsc
      FileSystem: { Path: TestData }

Reference in stub: DataSourceNames: [MyData] inside the Stubs entry (FB s03).

4. Controller block (optional — Redis control plane)

Controller:
  ServerName: HelloMocker          # byte-match with Runner MockerCommands[].ServerName (FB s03, LAB L6)
  Redis:
    Host: "127.0.0.1:6379"         # single "host:port" string (FB s14#7, LAB L6)

Boot log when configured: Initialized Redis controller for server 'HelloMocker' with instance id '...' and Started control handler 'CommandHandler' ... 'runner-to-mocker:command:hellomocker:<id>' (FB s13#11, LAB L6). When omitted: Controller startup skipped because 'Controller.ServerName' is not configured (LAB L5).

5. Verbatim golden (LAB-green, FB s14#2)

Servers:
  - Http:
      Port: 8080
      Endpoints:
        - Path: /hello
          Actions:
            - Name: HelloOk
              Method: Get
              TransactionStubName: HelloStub

Stubs:
  - Name: HelloStub
    Processor: StaticResponseProcessor
    ProcessorConfiguration:
      Body: hello
      StatusCode: 200
      ContentType: "text/plain; charset=utf-8"

Start: dotnet run --project Mocker -- run hello.mocker.yaml. Requires QaaS.Common.Processors in csproj.

6. Controller staged-swap golden (FB s14#7, LAB L6)

Controller:
  ServerName: HelloMocker
  Redis: {Host: "127.0.0.1:6379"}

Runner side adds MockerCommands[].ServerName: HelloMocker and Redis: {Host: "127.0.0.1:6379"}.

7. Verify

dotnet run --project Mocker -- template hello.mocker.yaml   # exit 0, no unknown-property warnings
dotnet run --project Mocker -- run hello.mocker.yaml        # wait for "HTTP Server started"
curl.exe http://127.0.0.1:8080/hello                        # body: hello, status: 200

Expected startup log: HTTP Server started. Listening on http://0.0.0.0:8080 (LAB L3).

Traps

#	Trap	Fix
s13#1	TransactionData: key	Use ProcessorConfiguration:
s13#5	Runner Route:/hello → //hello → 404	Runner Route has NO leading slash; Mocker Path /hello is correct
s13#7	Dockerfile runtime:10.0 → "Microsoft.AspNetCore.App not found"	Use aspnet:10.0
s13#8	Missing QaaS.Common.Processors → FTL + exit -532462766	Add PackageReference
s13#11	Docs claim Controller channel ready: HelloMocker	Real logs differ — see step 4
LAB L6	IsLocalhost:true in Docker container	Omit or set false → binds 0.0.0.0

Citations

• FB s03 (Mocker YAML blocks), FB s12 (9 processors), FB s13 (drift traps), FB s14#2/#7 (golden examples)