[health] add internal healthcheck command

Author: capcom6

Dockerfile.goreleaser

@@ -4,7 +4,7 @@ ARG TARGETPLATFORM
 ARG BINARY_NAME
 
 # Install certificates and timezone data
-RUN apk add --no-cache ca-certificates tzdata curl
+RUN apk add --no-cache ca-certificates tzdata
 
 # Set the Current Working Directory inside the container
 WORKDIR /app
@@ -21,7 +21,7 @@ USER guest
 ENTRYPOINT ["/docker-entrypoint.sh"]
 
 HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
-    CMD curl -fs http://localhost:3000/health/live
+    CMD [ "/app/app", "health" ]
 
 CMD [ "/app/app" ]
 

build/package/Dockerfile

@@ -33,8 +33,7 @@ FROM alpine:3 AS prod
 
 WORKDIR /app
 
-RUN apk add --no-cache tzdata \
-    curl
+RUN apk add --no-cache tzdata
 
 COPY scripts/docker-entrypoint.sh /docker-entrypoint.sh
 
@@ -48,6 +47,6 @@ USER guest
 ENTRYPOINT ["/docker-entrypoint.sh"]
 
 HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
-    CMD curl -fs http://localhost:3000/health/live
+    CMD [ "/app/app", "health" ]
 
 CMD [ "/app/app" ]

cmd/sms-gateway/main.go

@@ -3,12 +3,14 @@ package main
 import (
 	"os"
 
+	"github.com/android-sms-gateway/server/internal/health"
 	smsgateway "github.com/android-sms-gateway/server/internal/sms-gateway"
 	"github.com/android-sms-gateway/server/internal/worker"
 )
 
 const (
 	cmdWorker = "worker"
+	cmdHealth = "health"
 )
 
 //	@securitydefinitions.basic	ApiAuth
@@ -53,13 +55,18 @@ const (
 func main() {
 	args := os.Args[1:]
 	cmd := "start"
-	if len(args) > 0 && args[0] == cmdWorker {
-		cmd = cmdWorker
+	if len(args) > 0 {
+		cmd = args[0]
 	}
 
-	if cmd == cmdWorker {
+	switch cmd {
+	case cmdHealth:
+		health.Run()
+		return
+	case cmdWorker:
 		worker.Run()
-	} else {
-		smsgateway.Run()
+		return
 	}
+
+	smsgateway.Run()
 }

internal/health/app.go

@@ -0,0 +1,37 @@
+package health
+
+import (
+	"context"
+	"time"
+
+	"github.com/android-sms-gateway/server/internal/config"
+	"github.com/go-core-fx/logger"
+	"go.uber.org/fx"
+)
+
+func Run() {
+	fx.New(
+		fx.StartTimeout(time.Second),
+		logger.Module(),
+		logger.WithFxDefaultLogger(),
+		config.Module(),
+		module(),
+	).Run()
+}
+
+func module() fx.Option {
+	return fx.Module(
+		"health",
+		fx.Provide(NewChecker),
+		fx.Invoke(func(lc fx.Lifecycle, checker *Checker) {
+			lc.Append(fx.Hook{
+				OnStart: func(ctx context.Context) error {
+					return checker.Execute(ctx)
+				},
+				OnStop: func(_ context.Context) error {
+					return nil
+				},
+			})
+		}),
+	)
+}

internal/health/checker.go

@@ -0,0 +1,74 @@
+package health
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	httpclient "net/http"
+	"time"
+
+	"github.com/capcom6/go-infra-fx/http"
+	"go.uber.org/fx"
+	"go.uber.org/zap"
+)
+
+var ErrNotHealthy = errors.New("not healthy")
+
+type Checker struct {
+	config http.Config
+
+	shutdowner fx.Shutdowner
+	logger     *zap.Logger
+}
+
+func NewChecker(config http.Config, shutdowner fx.Shutdowner, logger *zap.Logger) *Checker {
+	return &Checker{
+		config:     config,
+		shutdowner: shutdowner,
+		logger:     logger,
+	}
+}
+
+func (c *Checker) Execute(ctx context.Context) error {
+	ctx, cancel := context.WithTimeout(ctx, time.Second)
+	defer cancel()
+
+	client := httpclient.DefaultClient
+
+	req, err := httpclient.NewRequestWithContext(
+		ctx,
+		httpclient.MethodGet,
+		"http://"+c.config.Listen+"/health/live",
+		nil,
+	)
+	if err != nil {
+		return fmt.Errorf("failed to create request: %w", err)
+	}
+
+	res, err := client.Do(req)
+	if err != nil {
+		return fmt.Errorf("failed to send request: %w", err)
+	}
+	defer res.Body.Close()
+
+	body, err := io.ReadAll(res.Body)
+	if err != nil {
+		return fmt.Errorf("failed to read response body: %w", err)
+	}
+
+	c.logger.Info(string(body))
+
+	if res.StatusCode >= httpclient.StatusBadRequest {
+		c.logger.Error("health check failed", zap.Int("status", res.StatusCode), zap.String("body", string(body)))
+		return fmt.Errorf("%w: health check failed: %s", ErrNotHealthy, string(body))
+	}
+
+	c.logger.Info("health check passed", zap.Int("status", res.StatusCode))
+
+	if shErr := c.shutdowner.Shutdown(); shErr != nil {
+		c.logger.Error("failed to shutdown", zap.Error(shErr))
+	}
+
+	return nil
+}