feat: game lobby service

lobby/internal/adapters/streamlagprobestub/probe.go

@@ -0,0 +1,61 @@
+// Package streamlagprobestub provides an in-memory ports.StreamLagProbe
+// implementation for tests that do not need a Redis instance. Production
+// code never wires this stub.
+package streamlagprobestub
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"galaxy/lobby/internal/ports"
+)
+
+// Probe is a concurrency-safe in-memory ports.StreamLagProbe. The zero
+// value reports `(0, false, nil)` for every stream until Set is called.
+type Probe struct {
+	mu       sync.Mutex
+	results  map[string]Result
+	fallback Result
+}
+
+// Result stores the value the probe reports for a stream.
+type Result struct {
+	Age   time.Duration
+	Found bool
+	Err   error
+}
+
+// NewProbe constructs one Probe with no preconfigured results.
+func NewProbe() *Probe {
+	return &Probe{results: make(map[string]Result)}
+}
+
+// Set installs the result the probe will return for stream.
+func (probe *Probe) Set(stream string, result Result) {
+	probe.mu.Lock()
+	defer probe.mu.Unlock()
+	probe.results[stream] = result
+}
+
+// SetFallback installs the result returned when no per-stream result is
+// configured.
+func (probe *Probe) SetFallback(result Result) {
+	probe.mu.Lock()
+	defer probe.mu.Unlock()
+	probe.fallback = result
+}
+
+// OldestUnprocessedAge satisfies ports.StreamLagProbe.
+func (probe *Probe) OldestUnprocessedAge(_ context.Context, stream, _ string) (time.Duration, bool, error) {
+	probe.mu.Lock()
+	defer probe.mu.Unlock()
+
+	if result, ok := probe.results[stream]; ok {
+		return result.Age, result.Found, result.Err
+	}
+	return probe.fallback.Age, probe.fallback.Found, probe.fallback.Err
+}
+
+// Compile-time interface assertion.
+var _ ports.StreamLagProbe = (*Probe)(nil)