SignatureProbe

Asks the program on a port the one question a {@see ServiceSignature} names — the seam between «the port accepts» ({@see ReachabilityProbe}) and «the service is the one declared», so a test can fake the answer and the real one ({@see HttpSignatureProbe}) stays one loopback request with a short timeout.

abstract public function answer(int $port, Milpa\Runtime\Stack\ServiceSignature $signature): ?int

The HTTP status the program on the port answered the signature's request with; null when no HTTP answer came.

Parameters