chore: establish local platform baseline

cmd/mock-alert-receiver/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"data-terminal-cloud/internal/mockalertreceiver"
+)
+
+func main() {
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil)).With("service", "mock-alert-receiver")
+	receiver, err := mockalertreceiver.New(mockalertreceiver.Options{
+		Secret: env("ALERT_WEBHOOK_SECRET", "local-alert-webhook-secret-32-bytes-minimum"), ClockSkew: 5 * time.Minute,
+	}, logger)
+	if err != nil {
+		logger.Error("configure mock alert receiver", "error", err)
+		os.Exit(1)
+	}
+	server := &http.Server{Addr: env("HTTP_ADDR", "0.0.0.0:8084"), Handler: receiver.Handler(), ReadHeaderTimeout: 5 * time.Second}
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+	go func() {
+		<-ctx.Done()
+		shutdown, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		defer cancel()
+		_ = server.Shutdown(shutdown)
+	}()
+	logger.Info("mock alert receiver started", "address", server.Addr)
+	if err = server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+		logger.Error("mock alert receiver stopped unexpectedly", "error", err)
+		os.Exit(1)
+	}
+}
+
+func env(key, fallback string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+	return fallback
+}