feat: improves healthcheck for swarm nodes (#3422)

Author: amir20

examples/docker.swarm.yml

@@ -1,9 +1,15 @@
 services:
   dozzle-service:
-    image: amir20/dozzle:latest
+    image: amir20/dozzle:local-test
     environment:
       - DOZZLE_LEVEL=debug
       - DOZZLE_MODE=swarm
+    healthcheck:
+      test: ["CMD", "/dozzle", "healthcheck"]
+      interval: 3s
+      timeout: 30s
+      retries: 5
+      start_period: 30s
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
     ports:

internal/support/docker/multi_host_service.go

@@ -26,6 +26,7 @@ type ClientManager interface {
 	RetryAndList() ([]ClientService, []error)
 	Subscribe(ctx context.Context, channel chan<- docker.Host)
 	Hosts(ctx context.Context) []docker.Host
+	LocalClients() []docker.Client
 }
 
 type MultiHostService struct {
@@ -156,3 +157,7 @@ func (m *MultiHostService) LocalHost() (docker.Host, error) {
 func (m *MultiHostService) SubscribeAvailableHosts(ctx context.Context, hosts chan<- docker.Host) {
 	m.manager.Subscribe(ctx, hosts)
 }
+
+func (m *MultiHostService) LocalClients() []docker.Client {
+	return m.manager.LocalClients()
+}

internal/support/docker/retriable_client_manager.go

@@ -179,3 +179,17 @@ func (m *RetriableClientManager) Hosts(ctx context.Context) []docker.Host {
 
 	return hosts
 }
+
+func (m *RetriableClientManager) LocalClients() []docker.Client {
+	services := m.List()
+
+	clients := make([]docker.Client, 0)
+
+	for _, service := range services {
+		if clientService, ok := service.(*dockerClientService); ok {
+			clients = append(clients, clientService.client)
+		}
+	}
+
+	return clients
+}

internal/support/docker/swarm_client_manager.go

@@ -229,3 +229,7 @@ func (m *SwarmClientManager) Hosts(ctx context.Context) []docker.Host {
 func (m *SwarmClientManager) String() string {
 	return fmt.Sprintf("SwarmClientManager{clients: %d}", len(m.clients))
 }
+
+func (m *SwarmClientManager) LocalClients() []docker.Client {
+	return []docker.Client{m.localClient}
+}

internal/web/healthcheck.go

@@ -9,17 +9,11 @@ import (
 func (h *handler) healthcheck(w http.ResponseWriter, r *http.Request) {
 	log.Debug().Msg("Executing healthcheck")
 
-	for _, host := range h.multiHostService.Hosts() {
-		if host.Type == "agent" {
-			log.Debug().Str("host", host.ID).Msg("Skipping agent host for healthcheck")
-			continue
-		}
-
-		_, err := h.multiHostService.ListContainersForHost(host.ID)
-		if err != nil {
-			log.Error().Err(err).Str("host", host.ID).Msg("Error listing containers")
-			http.Error(w, "Error listing containers", http.StatusInternalServerError)
-			return
+	clients := h.multiHostService.LocalClients()
+	for _, client := range clients {
+		if _, err := client.Ping(r.Context()); err != nil {
+			log.Error().Err(err).Str("host", client.Host().Name).Msg("error pinging host")
+			w.WriteHeader(http.StatusInternalServerError)
 		}
 	}