chore: filer healthz handler check filer store (#5208)

weed/server/filer_server.go

@@ -171,6 +171,7 @@ func NewFilerServer(defaultMux, readonlyMux *http.ServeMux, option *FilerOption)
 	}
 	if defaultMux != readonlyMux {
 		handleStaticResources(readonlyMux)
+		readonlyMux.HandleFunc("/healthz", fs.filerHealthzHandler)
 		readonlyMux.HandleFunc("/", fs.readonlyFilerHandler)
 	}
 

weed/server/filer_server_handlers.go

@@ -1,6 +1,7 @@
 package weed_server
 
 import (
+	"context"
 	"errors"
 	"net/http"
 	"os"
@@ -9,7 +10,9 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/seaweedfs/seaweedfs/weed/filer"
 	"github.com/seaweedfs/seaweedfs/weed/glog"
+	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
 	"github.com/seaweedfs/seaweedfs/weed/security"
 	"github.com/seaweedfs/seaweedfs/weed/util"
 
@@ -220,5 +223,10 @@ func (fs *FilerServer) maybeCheckJwtAuthorization(r *http.Request, isWrite bool)
 
 func (fs *FilerServer) filerHealthzHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Server", "SeaweedFS Filer "+util.VERSION)
-	w.WriteHeader(http.StatusOK)
+	if _, err := fs.filer.Store.FindEntry(context.Background(), filer.TopicsDir); err != nil && err != filer_pb.ErrNotFound {
+		glog.Warningf("filerHealthzHandler FindEntry: %+v", err)
+		w.WriteHeader(http.StatusServiceUnavailable)
+	} else {
+		w.WriteHeader(http.StatusOK)
+	}
 }