feat(agent): introduce connector label for selective management

This commit introduces the ability to dynamically configure which
containers are added to ShellHub as devices when the agent is started in
connector mode. By allowing users to specify a label for the containers,
the ShellHub agent can now selectively manage containers based on
user-defined criteria.

This enhancement improves the flexibility and usability of the ShellHub
agent, enabling more precise control over which containers are
integrated into the system, ultimately streamlining device management.

Author: henrybarreto

agent/main.go

@@ -227,7 +227,7 @@ func main() {
 			logger.Info("Starting ShellHub Agent Connector")
 
 			connector.ConnectorVersion = AgentVersion
-			connector, err := connector.NewDockerConnector(cfg.ServerAddress, cfg.TenantID, cfg.PrivateKeys)
+			connector, err := connector.NewDockerConnector(cfg)
 			if err != nil {
 				logger.Fatal("Failed to create ShellHub Agent Connector")
 			}

install.sh

@@ -25,6 +25,7 @@ podman_install() {
             MODE="connector"
             DEFAULT_CONTAINER_NAME="shellhub-connector"
             ARGS="$ARGS -e SHELLHUB_PRIVATE_KEYS=${PRIVATE_KEYS:-/host/etc/shellhub/connector/keys}"
+            ARGS="$ARGS -e SHELLHUB_CONNECTOR_LABEL=${SHELLHUB_CONNECTOR_LABEL}"
 
             echo "🚀 Starting ShellHub container in Docker Connector mode..."
             shift 1
@@ -96,6 +97,7 @@ docker_install() {
             MODE="connector"
             DEFAULT_CONTAINER_NAME="shellhub-connector"
             ARGS="$ARGS -e SHELLHUB_PRIVATE_KEYS=${PRIVATE_KEYS:-/host/etc/shellhub/connector/keys}"
+            ARGS="$ARGS -e SHELLHUB_CONNECTOR_LABEL=${SHELLHUB_CONNECTOR_LABEL}"
 
             echo "🚀 Starting ShellHub container in Docker Connector mode..."
             shift 1

pkg/agent/connector/docker.go

@@ -9,6 +9,7 @@ import (
 	"github.com/Masterminds/semver"
 	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/events"
+	"github.com/docker/docker/api/types/filters"
 	dockerclient "github.com/docker/docker/client"
 	"github.com/shellhub-io/shellhub/pkg/agent"
 	"github.com/shellhub-io/shellhub/pkg/api/client"
@@ -30,6 +31,8 @@ type DockerConnector struct {
 	cli *dockerclient.Client
 	// privateKeys is the path to the directory that contains the private keys for the containers.
 	privateKeys string
+	// Label is the label used to identify the containers managed by the ShellHub agent.
+	Label string
 	// cancels is a map that contains the cancel functions for each container.
 	// This is used to stop the agent for a container, marking as done its context and closing the agent.
 	cancels map[string]context.CancelFunc
@@ -55,6 +58,9 @@ type Config struct {
 	// has a direct impact of the bandwidth used by the device when in idle
 	// state. Default is 30 seconds.
 	KeepAliveInterval int `env:"KEEPALIVE_INTERVAL,overwrite,default=30"`
+
+	// Label is the label used to identify the containers managed by the ShellHub agent.
+	Label string `env:"CONNECTOR_LABEL,default="`
 }
 
 func LoadConfigFromEnv() (*Config, map[string]interface{}, error) {
@@ -73,39 +79,44 @@ func LoadConfigFromEnv() (*Config, map[string]interface{}, error) {
 	return cfg, nil, nil
 }
 
-func NewDockerConnectorWithClient(cli *dockerclient.Client, server string, tenant string, privateKey string) (Connector, error) {
-	return &DockerConnector{
-		server:      server,
-		tenant:      tenant,
-		cli:         cli,
-		privateKeys: privateKey,
-		cancels:     make(map[string]context.CancelFunc),
-	}, nil
-}
-
 // NewDockerConnector creates a new [Connector] that uses Docker as the container runtime.
-func NewDockerConnector(server string, tenant string, privateKey string) (Connector, error) {
+func NewDockerConnector(config *Config) (Connector, error) {
 	cli, err := dockerclient.NewClientWithOpts(dockerclient.FromEnv, dockerclient.WithAPIVersionNegotiation())
 	if err != nil {
 		return nil, err
 	}
 
 	return &DockerConnector{
-		server:      server,
-		tenant:      tenant,
 		cli:         cli,
-		privateKeys: privateKey,
+		server:      config.ServerAddress,
+		tenant:      config.TenantID,
+		privateKeys: config.PrivateKeys,
+		Label:       config.Label,
 		cancels:     make(map[string]context.CancelFunc),
 	}, nil
 }
 
 // events returns the docker events.
 func (d *DockerConnector) events(ctx context.Context) (<-chan events.Message, <-chan error) {
-	return d.cli.Events(ctx, events.ListOptions{})
+	filters := filters.NewArgs()
+	if d.Label != "" {
+		filters.Add("label", d.Label)
+	}
+
+	return d.cli.Events(ctx, events.ListOptions{
+		Filters: filters,
+	})
 }
 
 func (d *DockerConnector) List(ctx context.Context) ([]Container, error) {
-	containers, err := d.cli.ContainerList(ctx, container.ListOptions{})
+	filters := filters.NewArgs()
+	if d.Label != "" {
+		filters.Add("label", d.Label)
+	}
+
+	containers, err := d.cli.ContainerList(ctx, container.ListOptions{
+		Filters: filters,
+	})
 	if err != nil {
 		return nil, err
 	}
@@ -187,7 +198,7 @@ func (d *DockerConnector) Listen(ctx context.Context) error {
 		case err := <-errs:
 			return err
 		case container := <-events:
-			// NOTICE: "start" and "die" Docker's events are call every time a new container start or stop,
+			// NOTE: "start" and "die" Docker's events are call every time a new container start or stop,
 			// independently how the command was run. For example, if a container was started with `docker run -d`, the
 			// "start" event will be called, but if the same container was started with `docker start <container-id>`,
 			// the "start" event will be called too. The same happens with the "die" event.