Implement health check for deploy. Make version endpoint to return revision if not set

internal/api/health/health_handler.go

@@ -0,0 +1,46 @@
+package health
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+
+	"payouts/internal/service/database"
+)
+
+// Route health route
+const Route = "/health"
+
+// New constructs a new health Handler.
+func New(dbService database.Service) (Handler, error) {
+	return &handler{
+		dbService: dbService,
+	}, nil
+}
+
+type handler struct {
+	dbService database.Service
+}
+
+// HealthHandler handles the health check requests
+func (h *handler) Health(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+	w.Header().Set("Content-Type", "application/json")
+
+	status := map[string]any{}
+
+	// Check database connection
+	err := h.dbService.HealthCheck()
+	if err != nil {
+		w.WriteHeader(http.StatusServiceUnavailable)
+		status["Error"] = fmt.Sprintf("%v", err)
+		slog.Error("Health check failed", slog.String("error", status["Error"].(string)))
+	} else {
+		w.WriteHeader(http.StatusOK)
+	}
+	status["OK"] = (err == nil)
+
+	encoder := json.NewEncoder(w)
+	encoder.Encode(status)
+}

internal/api/health/module.go

@@ -0,0 +1,16 @@
+package health
+
+import (
+	"net/http"
+
+	"go.uber.org/fx"
+)
+
+var Module = fx.Options(
+	fx.Provide(New),
+)
+
+// Handler health handler interface
+type Handler interface {
+	Health(http.ResponseWriter, *http.Request)
+}

internal/api/module.go

@@ -11,6 +11,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.uber.org/fx"
 
+	"payouts/internal/api/health"
 	"payouts/internal/api/payout"
 	"payouts/internal/api/user"
 	"payouts/internal/api/version"
@@ -21,6 +22,7 @@ import (
 // Module is a fx module
 var Module = fx.Options(
 	user.Module,
+	health.Module,
 	payout.Module,
 	version.Module,
 	monitoring.Module,
@@ -40,6 +42,7 @@ type Params struct {
 	PayoutHandler payout.Handler
 	UserHandler   user.Handler
 	Version       version.Handler
+	HealthHandler health.Handler
 
 	Metrics monitoring.Metrics
 }
@@ -50,7 +53,10 @@ func RegisterRoutes(p Params, lc fx.Lifecycle) {
 	router := mux.NewRouter()
 	router.StrictSlash(true)
 
+	// Version endpoint
 	router.HandleFunc(version.Route, p.Version.VersionHandler).Methods(http.MethodGet)
+	// Health check endpoint
+	router.HandleFunc(health.Route, p.HealthHandler.Health).Methods(http.MethodGet)
 
 	if p.AppConfig.Server.EnablePProfEndpoints {
 		router.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)

internal/api/version/version_handler.go

@@ -3,6 +3,7 @@ package version
 import (
 	"io"
 	"net/http"
+	"runtime/debug"
 
 	"go.uber.org/fx"
 
@@ -39,7 +40,20 @@ type handler struct {
 func (h *handler) VersionHandler(w http.ResponseWriter, r *http.Request) {
 	defer r.Body.Close()
 
+	ver := h.version
+	if ver == "unknown" {
+		buildInfo, ok := debug.ReadBuildInfo()
+		if ok {
+			for _, setting := range buildInfo.Settings {
+				if setting.Key == "vcs.revision" {
+					ver = ver + "-" + setting.Value
+					break
+				}
+			}
+		}
+	}
+
 	w.Header().Set("Content-Type", "text/plain")
 	w.WriteHeader(http.StatusOK)
-	io.WriteString(w, h.version)
+	io.WriteString(w, ver+"\n")
 }