feat: implement container network attaching

Containers can be attached:

- after they are created, but before they are started
- after a successful deploy, but before the proxy reloads

This allows folks to have flexibility around when they would like a container to be made available to a network.

plugins/network/subcommands.go

@@ -1,11 +1,132 @@
 package network
 
 import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
 	"strings"
 
 	"github.com/dokku/dokku/plugins/common"
 )
 
+// CommandCreate is an alias for "docker network create"
+func CommandCreate(networkName string) error {
+	common.LogInfo1Quiet(fmt.Sprintf("Creating network %v", networkName))
+	createCmd := common.NewShellCmd(strings.Join([]string{
+		common.DockerBin(),
+		"network",
+		"create",
+		"--attachable",
+		"--label",
+		"com.dokku.network=true",
+		"--label",
+		fmt.Sprintf("com.dokku.network-name=%v", networkName),
+		networkName,
+	}, " "))
+	var stderr bytes.Buffer
+	createCmd.ShowOutput = false
+	createCmd.Command.Stderr = &stderr
+	_, err := createCmd.Output()
+
+	if err != nil {
+		err = errors.New(strings.TrimSpace(stderr.String()))
+	}
+
+	return err
+}
+
+// CommandDestroy is an alias for "docker network rm"
+func CommandDestroy(networkName string, forceDestroy bool) error {
+	if os.Getenv("DOKKU_APPS_FORCE_DELETE") == "1" {
+		forceDestroy = true
+	}
+
+	if !forceDestroy {
+		common.LogWarn("WARNING: Potentially Destructive Action")
+		common.LogWarn(fmt.Sprintf("This command will destroy network %v.", networkName))
+		common.LogWarn(fmt.Sprintf("To proceed, type \"%v\"", networkName))
+		fmt.Print("> ")
+		var response string
+		_, err := fmt.Scanln(&response)
+		if err != nil {
+			return err
+		}
+
+		if response != networkName {
+			common.LogStderr("Confirmation did not match test. Aborted.")
+			os.Exit(1)
+			return nil
+		}
+	}
+
+	common.LogInfo1Quiet(fmt.Sprintf("Destroying network %v", networkName))
+	destroyCmd := common.NewShellCmd(strings.Join([]string{
+		common.DockerBin(),
+		"network",
+		"rm",
+		networkName,
+	}, " "))
+	var stderr bytes.Buffer
+	destroyCmd.ShowOutput = false
+	destroyCmd.Command.Stderr = &stderr
+	_, err := destroyCmd.Output()
+
+	if err != nil {
+		err = errors.New(strings.TrimSpace(stderr.String()))
+	}
+
+	return err
+}
+
+// CommandExists checks if a network exists
+func CommandExists(networkName string) error {
+	exists := false
+	if networkName == "" {
+		return errors.New("No network name specified")
+	}
+
+	networks, err := ListNetworks()
+	if err != nil {
+		return err
+	}
+
+	for _, n := range networks {
+		if networkName == n {
+			exists = true
+			break
+		}
+	}
+
+	if exists {
+		common.LogInfo1Quiet("Network exists")
+	} else {
+		common.LogFail("Network does not exist")
+	}
+
+	return nil
+}
+
+// CommandInfo is an alias for "docker network inspect"
+func CommandInfo() error {
+	return nil
+}
+
+// CommandList is an alias for "docker network ls"
+func CommandList() error {
+	networks, err := ListNetworks()
+	if err != nil {
+		return err
+	}
+
+	common.LogInfo2Quiet("Networks")
+	for _, networkName := range networks {
+		fmt.Println(networkName)
+	}
+
+	return nil
+}
+
 // CommandRebuildall rebuilds network settings for all apps
 func CommandRebuildall() {
 	apps, err := common.DokkuApps()
@@ -44,5 +165,18 @@ func CommandSet(appName string, property string, value string) {
 		value = "false"
 	}
 
+	attachProperites := map[string]bool{
+		"attach-post-create": true,
+		"attach-post-deploy": true,
+	}
+
+	invalidNetworks := map[string]bool{
+		"host":   true,
+		"bridge": true,
+	}
+	if attachProperites[property] && invalidNetworks[value] {
+		common.LogFail("Invalid network name specified for attach")
+	}
+
 	common.CommandPropertySet("network", appName, property, value, DefaultProperties)
 }