implement health monitor for file server

internal/route/fileserver.go

@@ -2,7 +2,6 @@ package route
 
 import (
 	"net/http"
-	"time"
 
 	"github.com/yusing/go-proxy/internal/common"
 	gphttp "github.com/yusing/go-proxy/internal/net/http"
@@ -21,11 +20,12 @@ type (
 	FileServer struct {
 		*Route
 
+		Health *monitor.FileServerHealthMonitor `json:"health"`
+
 		task         *task.Task
 		middleware   *middleware.Middleware
 		handler      http.Handler
 		accessLogger *accesslog.AccessLogger
-		startTime    time.Time
 	}
 )
 
@@ -49,8 +49,7 @@ func NewFileServer(base *Route) (*FileServer, E.Error) {
 
 // Start implements task.TaskStarter.
 func (s *FileServer) Start(parent task.Parent) E.Error {
-	s.startTime = time.Now()
+	s.task = parent.Subtask("fileserver."+s.TargetName(), false)
-	s.task = parent.Subtask("fileserver."+s.Name(), false)
 
 	pathPatterns := s.PathPatterns
 	switch {
@@ -90,6 +89,11 @@ func (s *FileServer) Start(parent task.Parent) E.Error {
 		s.task.OnCancel("reset_metrics", metricsLogger.ResetMetrics)
 	}
 
+	if s.UseHealthCheck() {
+		s.Health = monitor.NewFileServerHealthMonitor(s.TargetName(), s.HealthCheck, s.Root)
+		s.Health.Start(s.task)
+	}
+
 	routes.SetHTTPRoute(s.TargetName(), s)
 	s.task.OnCancel("entrypoint_remove_route", func() {
 		routes.DeleteHTTPRoute(s.TargetName())
@@ -114,40 +118,6 @@ func (s *FileServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 }
 
-// Status implements health.HealthMonitor.
+func (s *FileServer) HealthMonitor() health.HealthMonitor {
-func (s *FileServer) Status() health.Status {
+	return s.Health
-	return health.StatusHealthy
-}
-
-// Uptime implements health.HealthMonitor.
-func (s *FileServer) Uptime() time.Duration {
-	return time.Since(s.startTime)
-}
-
-// Latency implements health.HealthMonitor.
-func (s *FileServer) Latency() time.Duration {
-	return 0
-}
-
-// MarshalJSON implements json.Marshaler.
-func (s *FileServer) MarshalJSON() ([]byte, error) {
-	return (&monitor.JSONRepresentation{
-		Name:     s.Alias,
-		Config:   nil,
-		Status:   s.Status(),
-		Started:  s.startTime,
-		Uptime:   s.Uptime(),
-		Latency:  s.Latency(),
-		LastSeen: time.Now(),
-		Detail:   "",
-		URL:      nil,
-	}).MarshalJSON()
-}
-
-func (s *FileServer) String() string {
-	return "FileServer " + s.Alias
-}
-
-func (s *FileServer) Name() string {
-	return s.Alias
 }

internal/watcher/health/monitor/fileserver.go

@@ -0,0 +1,36 @@
+package monitor
+
+import (
+	"os"
+	"time"
+
+	"github.com/yusing/go-proxy/internal/watcher/health"
+)
+
+type FileServerHealthMonitor struct {
+	*monitor
+	path string
+}
+
+func NewFileServerHealthMonitor(alias string, config *health.HealthCheckConfig, path string) *FileServerHealthMonitor {
+	mon := &FileServerHealthMonitor{path: path}
+	mon.monitor = newMonitor(nil, config, mon.CheckHealth)
+	mon.service = alias
+	return mon
+}
+
+func (s *FileServerHealthMonitor) CheckHealth() (*health.HealthCheckResult, error) {
+	start := time.Now()
+	_, err := os.Stat(s.path)
+
+	detail := ""
+	if err != nil {
+		detail = err.Error()
+	}
+
+	return &health.HealthCheckResult{
+		Healthy: err == nil,
+		Latency: time.Since(start),
+		Detail:  detail,
+	}, nil
+}