feat: enables swarm cluster to connect to external agents (#3394)

Co-authored-by: Mitch Brown <mitch@mitchbrown.ca>

README.md

@@ -65,7 +65,7 @@ Dozzle can be used to monitor multiple Docker hosts. You can run Dozzle in agent
 
     $ docker run -v /var/run/docker.sock:/var/run/docker.sock -p 7007:7007 amir20/dozzle:latest agent
 
-See the [Agent Mode](https://dozzle.dev/guide/agent-mode) documentation for more details.
+See the [Agent Mode](https://dozzle.dev/guide/agent) documentation for more details.
 
 ## Technical Details
 

docs/guide/swarm-mode.md

@@ -74,3 +74,34 @@ secrets:
 ```
 
 In this example, `users.yml` file is stored in a Docker secret. It is the same as the [simple authentication](/guide/authentication#generating-users-yml) example.
+
+## Adding standalone Agents to Swarm Mode
+
+From version v8.8.x, Dozzle supports adding standalone [Agents](/guide/agent) when running in Swarm Mode.
+
+Simply [add the remote agent](/guide/agent#how-to-connect-to-an-agent) to your Swarm compose in the same way you normally would.
+
+> [!NOTE]
+> While remote agents are supported, remote connections such as socket proxy are not supported.
+
+```yml
+services:
+  dozzle:
+    image: amir20/dozzle:latest
+    environment:
+      - DOZZLE_MODE=swarm
+      - DOZZLE_REMOTE_AGENT=agent:7007
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+    ports:
+      - 8080:8080
+    networks:
+      - dozzle
+    deploy:
+      mode: global
+networks:
+  dozzle:
+    driver: overlay
+```
+
+The remote agent(s) will now display alongside the other nodes in Dozzle.

examples/docker.swarm.yml

@@ -1,9 +1,10 @@
 services:
   dozzle-service:
-    image: amir20/dozzle:latest
+    image: amir20/dozzle:local-test
     environment:
       - DOZZLE_LEVEL=debug
       - DOZZLE_MODE=swarm
+      - DOZZLE_REMOTE_AGENT=198.19.248.6:7007
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock
     ports:

internal/docker/client.go

@@ -342,6 +342,7 @@ func (d *httpClient) Ping(ctx context.Context) (types.Ping, error) {
 }
 
 func (d *httpClient) Host() Host {
+	log.Debug().Str("host", d.host.Name).Msg("Fetching host")
 	return d.host
 }
 

internal/support/cli/args.go

@@ -31,6 +31,7 @@ type Args struct {
 	Healthcheck     *HealthcheckCmd     `arg:"subcommand:healthcheck" help:"checks if the server is running"`
 	Generate        *GenerateCmd        `arg:"subcommand:generate" help:"generates a configuration file for simple auth"`
 	Agent           *AgentCmd           `arg:"subcommand:agent" help:"starts the agent"`
+	AgentTest       *AgentTestCmd       `arg:"subcommand:agent-test" help:"tests an agent"`
 }
 
 type HealthcheckCmd struct {
@@ -40,6 +41,10 @@ type AgentCmd struct {
 	Addr string `arg:"env:DOZZLE_AGENT_ADDR" default:":7007" help:"sets the host:port to bind for the agent"`
 }
 
+type AgentTestCmd struct {
+	Address string `arg:"positional"`
+}
+
 type GenerateCmd struct {
 	Username string `arg:"positional"`
 	Password string `arg:"--password, -p" help:"sets the password for the user"`

internal/support/docker/retriable_client_manager.go

@@ -10,6 +10,7 @@ import (
 	"github.com/amir20/dozzle/internal/agent"
 	"github.com/amir20/dozzle/internal/docker"
 	"github.com/puzpuzpuz/xsync/v3"
+	"github.com/samber/lo"
 	lop "github.com/samber/lo/parallel"
 
 	"github.com/rs/zerolog/log"
@@ -136,11 +137,7 @@ func (m *RetriableClientManager) List() []ClientService {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
 
-	clients := make([]ClientService, 0, len(m.clients))
-	for _, client := range m.clients {
-		clients = append(clients, client)
-	}
-	return clients
+	return lo.Values(m.clients)
 }
 
 func (m *RetriableClientManager) Find(id string) (ClientService, bool) {

internal/support/docker/swarm_client_manager.go

@@ -27,6 +27,7 @@ type SwarmClientManager struct {
 	localIPs     []string
 	name         string
 	timeout      time.Duration
+	agentManager *RetriableClientManager
 }
 
 func localIPs() []string {
@@ -46,7 +47,7 @@ func localIPs() []string {
 	return ips
 }
 
-func NewSwarmClientManager(localClient docker.Client, certs tls.Certificate, timeout time.Duration) *SwarmClientManager {
+func NewSwarmClientManager(localClient docker.Client, certs tls.Certificate, timeout time.Duration, agentManager *RetriableClientManager) *SwarmClientManager {
 	clientMap := make(map[string]ClientService)
 	localService := NewDockerClientService(localClient)
 	clientMap[localClient.Host().ID] = localService
@@ -75,11 +76,13 @@ func NewSwarmClientManager(localClient docker.Client, certs tls.Certificate, tim
 		localIPs:     localIPs(),
 		name:         serviceName,
 		timeout:      timeout,
+		agentManager: agentManager,
 	}
 }
 
 func (m *SwarmClientManager) Subscribe(ctx context.Context, channel chan<- docker.Host) {
 	m.subscribers.Store(ctx, channel)
+	m.agentManager.Subscribe(ctx, channel)
 
 	go func() {
 		<-ctx.Done()
@@ -174,6 +177,8 @@ func (m *SwarmClientManager) RetryAndList() ([]ClientService, []error) {
 
 	m.mu.Unlock()
 
+	m.agentManager.RetryAndList()
+
 	return m.List(), errors
 }
 
@@ -181,7 +186,10 @@ func (m *SwarmClientManager) List() []ClientService {
 	m.mu.RLock()
 	defer m.mu.RUnlock()
 
-	return lo.Values(m.clients)
+	agents := m.agentManager.List()
+	clients := lo.Values(m.clients)
+
+	return append(agents, clients...)
 }
 
 func (m *SwarmClientManager) Find(id string) (ClientService, bool) {
@@ -189,13 +197,20 @@ func (m *SwarmClientManager) Find(id string) (ClientService, bool) {
 	defer m.mu.RUnlock()
 
 	client, ok := m.clients[id]
+
+	if !ok {
+		client, ok = m.agentManager.Find(id)
+	}
+
 	return client, ok
 }
 
 func (m *SwarmClientManager) Hosts(ctx context.Context) []docker.Host {
-	clients := m.List()
+	m.mu.RLock()
+	clients := lo.Values(m.clients)
+	m.mu.RUnlock()
 
-	return lop.Map(clients, func(client ClientService, _ int) docker.Host {
+	swarmNodes := lop.Map(clients, func(client ClientService, _ int) docker.Host {
 		host, err := client.Host(ctx)
 		if err != nil {
 			log.Warn().Err(err).Str("id", host.ID).Msg("error getting host from client")
@@ -208,6 +223,7 @@ func (m *SwarmClientManager) Hosts(ctx context.Context) []docker.Host {
 		return host
 	})
 
+	return append(m.agentManager.Hosts(ctx), swarmNodes...)
 }
 
 func (m *SwarmClientManager) String() string {

main.go

@@ -126,6 +126,27 @@ func main() {
 			if _, err := os.Stdout.Write(buffer.Bytes()); err != nil {
 				log.Fatal().Err(err).Msg("Failed to write to stdout")
 			}
+
+		case *cli.AgentTestCmd:
+			certs, err := cli.ReadCertificates(certs)
+			if err != nil {
+				log.Fatal().Err(err).Msg("Could not read certificates")
+			}
+
+			log.Info().Str("endpoint", args.AgentTest.Address).Msg("Connecting to agent")
+
+			agent, err := agent.NewClient(args.AgentTest.Address, certs)
+			if err != nil {
+				log.Fatal().Err(err).Str("endpoint", args.AgentTest.Address).Msg("error connecting to agent")
+			}
+			ctx, cancel := context.WithTimeout(context.Background(), args.Timeout)
+			defer cancel()
+			host, err := agent.Host(ctx)
+			if err != nil {
+				log.Fatal().Err(err).Str("endpoint", args.AgentTest.Address).Msg("error fetching host info for agent")
+			}
+
+			log.Info().Str("endpoint", args.AgentTest.Address).Str("version", host.AgentVersion).Str("name", host.Name).Str("id", host.ID).Msg("Successfully connected to agent")
 		}
 
 		os.Exit(0)
@@ -157,7 +178,8 @@ func main() {
 		if err != nil {
 			log.Fatal().Err(err).Msg("Could not read certificates")
 		}
-		manager := docker_support.NewSwarmClientManager(localClient, certs, args.Timeout)
+		agentManager := docker_support.NewRetriableClientManager(args.RemoteAgent, args.Timeout, certs)
+		manager := docker_support.NewSwarmClientManager(localClient, certs, args.Timeout, agentManager)
 		multiHostService = docker_support.NewMultiHostService(manager, args.Timeout)
 		log.Info().Msg("Starting in swarm mode")
 		listener, err := net.Listen("tcp", ":7007")