feat: expose whether a network was created by dokku

`network:list` and `network:info` now expose a `DokkuManaged` boolean derived from the `com.dokku.network-name` label that `network:create` applies, and `network:list` gains a `--dokku-managed` flag to restrict output to dokku-created networks. This lets tooling distinguish networks dokku created from Docker built-ins and networks created by other tooling such as compose.

plugins/network/functions.go

@@ -11,15 +11,21 @@ import (
 	"github.com/dokku/dokku/plugins/common"
 )
 
+// dokkuNetworkNameLabel is the docker label network:create applies to every
+// network it creates. Its presence is the marker used to identify a network as
+// dokku-managed.
+const dokkuNetworkNameLabel = "com.dokku.network-name"
+
 type DockerNetwork struct {
-	CreatedAt time.Time
-	Driver    string
-	ID        string
-	Internal  bool
-	IPv6      bool
-	Labels    map[string]string
-	Name      string
-	Scope     string
+	CreatedAt    time.Time
+	DokkuManaged bool
+	Driver       string
+	ID           string
+	Internal     bool
+	IPv6         bool
+	Labels       map[string]string
+	Name         string
+	Scope        string
 }
 
 // attachAppToNetwork attaches a container to a network
@@ -206,6 +212,10 @@ func getNetworks() (map[string]DockerNetwork, error) {
 			network.Labels[key] = value
 		}
 
+		if _, ok := network.Labels[dokkuNetworkNameLabel]; ok {
+			network.DokkuManaged = true
+		}
+
 		networks[network.Name] = network
 	}
 

plugins/network/src/commands/commands.go

@@ -22,7 +22,7 @@ Additional commands:`
     network:destroy <network>, Destroys a docker network
     network:exists <network>, Checks if a docker network exists
     network:info <network> [--format text|json], Outputs information about a docker network
-    network:list [--format text|json], Lists all docker networks
+    network:list [--format text|json] [--dokku-managed], Lists all docker networks
     network:rebuild <app>, Rebuilds network settings for an app
     network:rebuildall, Rebuild network settings for all apps
     network:report [<app>] [<flag>], Displays a network report for one or more apps

plugins/network/src/subcommands/subcommands.go

@@ -43,8 +43,9 @@ func main() {
 	case "list":
 		args := flag.NewFlagSet("network:list", flag.ExitOnError)
 		format := args.String("format", "text", "format: [ text | json ]")
+		dokkuManaged := args.Bool("dokku-managed", false, "show only dokku-managed networks")
 		args.Parse(os.Args[2:])
-		err = network.CommandList(*format)
+		err = network.CommandList(*format, *dokkuManaged)
 	case "rebuild":
 		args := flag.NewFlagSet("network:rebuild", flag.ExitOnError)
 		args.Parse(os.Args[2:])

plugins/network/subcommands.go

@@ -15,7 +15,7 @@ func CommandCreate(networkName string) error {
 	common.LogInfo1Quiet(fmt.Sprintf("Creating network %v", networkName))
 	result, err := common.CallExecCommand(common.ExecCommandInput{
 		Command: common.DockerBin(),
-		Args:    []string{"network", "create", "--attachable", "--label", fmt.Sprintf("com.dokku.network-name=%v", networkName), networkName},
+		Args:    []string{"network", "create", "--attachable", "--label", fmt.Sprintf("%s=%v", dokkuNetworkNameLabel, networkName), networkName},
 	})
 	if err != nil {
 		return fmt.Errorf("Unable to create network: %w", err)
@@ -103,18 +103,19 @@ func CommandInfo(networkName string, format string) error {
 		return nil
 	}
 
-	length := 10
+	length := 16
 	common.LogInfo2Quiet(fmt.Sprintf("%s network information", networkName))
 	common.LogVerbose(fmt.Sprintf("%s%s", common.RightPad("ID:", length, " "), network.ID))
 	common.LogVerbose(fmt.Sprintf("%s%s", common.RightPad("Name:", length, " "), network.Name))
 	common.LogVerbose(fmt.Sprintf("%s%s", common.RightPad("Driver:", length, " "), network.Driver))
 	common.LogVerbose(fmt.Sprintf("%s%s", common.RightPad("Scope:", length, " "), network.Scope))
+	common.LogVerbose(fmt.Sprintf("%s%v", common.RightPad("Dokku managed:", length, " "), network.DokkuManaged))
 
 	return nil
 }
 
 // CommandList is an alias for "docker network ls"
-func CommandList(format string) error {
+func CommandList(format string, dokkuManaged bool) error {
 	networks, err := getNetworks()
 	if err != nil {
 		return err
@@ -123,6 +124,9 @@ func CommandList(format string) error {
 	if format == "json" {
 		networkList := []DockerNetwork{}
 		for _, network := range networks {
+			if dokkuManaged && !network.DokkuManaged {
+				continue
+			}
 			networkList = append(networkList, network)
 		}
 		out, err := json.Marshal(networkList)
@@ -135,6 +139,9 @@ func CommandList(format string) error {
 
 	common.LogInfo2Quiet("Networks")
 	for _, network := range networks {
+		if dokkuManaged && !network.DokkuManaged {
+			continue
+		}
 		fmt.Println(network.Name)
 	}