ReachabilityProbe

Answers whether something on this host accepts a connection on a port — the one measurement anything reading the declared stack makes. A declared service is data; whether it is RUNNING is a fact a reader can only observe. The probe is the seam between the two, so a test can fake the answer and the real one ({@see TcpProbe}) stays a loopback connect with a short timeout — no Docker, no orchestration (greenhouse decisions/0201).

abstract public function reachable(int $port): bool

True when a TCP connection to the port on loopback succeeds within the probe's timeout.

Parameters

abstract public function host(): string

The host the probe connects to — what a reader reports next to the port it tried.