@@ -17,4 +17,5 @@ type Backend interface {

 	ConnectContainerToNetwork(containerName, networkName string, endpointConfig *network.EndpointSettings) error

 	DisconnectContainerFromNetwork(containerName string, networkName string, force bool) error

 	DeleteNetwork(name string) error

+	NetworksPrune(config *types.NetworksPruneConfig) (*types.NetworksPruneReport, error)

 }

@@ -37,6 +37,7 @@ func (r *networkRouter) initRoutes() {

 		router.NewPostRoute("/networks/create", r.postNetworkCreate),

 		router.NewPostRoute("/networks/{id:.*}/connect", r.postNetworkConnect),

 		router.NewPostRoute("/networks/{id:.*}/disconnect", r.postNetworkDisconnect),

+		router.NewPostRoute("/networks/prune", r.postNetworksPrune),

 		// DELETE

 		router.NewDeleteRoute("/networks/{id:.*}", r.deleteNetwork),

 	}

@@ -274,3 +274,24 @@ func buildEndpointResource(id string, name string, info libnetwork.EndpointInfo)

 	}

 	return er

 }

+

+func (n *networkRouter) postNetworksPrune(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

+	if err := httputils.ParseForm(r); err != nil {

+		return err

+	}

+

+	if err := httputils.CheckForJSON(r); err != nil {

+		return err

+	}

+

+	var cfg types.NetworksPruneConfig

+	if err := json.NewDecoder(r.Body).Decode(&cfg); err != nil {

+		return err

+	}

+

+	pruneReport, err := n.backend.NetworksPrune(&cfg)

+	if err != nil {

+		return err

+	}

+	return httputils.WriteJSON(w, http.StatusOK, pruneReport)

+}

@@ -522,6 +522,11 @@ type ContainersPruneConfig struct {

 type VolumesPruneConfig struct {

 }

+// NetworksPruneConfig contains the configuration for Remote API:

+// POST "/networks/prune"

+type NetworksPruneConfig struct {

+}

+

 // ContainersPruneReport contains the response for Remote API:

 // POST "/containers/prune"

 type ContainersPruneReport struct {

@@ -542,3 +547,9 @@ type ImagesPruneReport struct {

 	ImagesDeleted  []ImageDelete

 	SpaceReclaimed uint64

 }

+

+// NetworksPruneReport contains the response for Remote API:

+// POST "/networks/prune"

+type NetworksPruneReport struct {

+	NetworksDeleted []string

+}

@@ -26,6 +26,7 @@ func NewNetworkCommand(dockerCli *command.DockerCli) *cobra.Command {

 		newInspectCommand(dockerCli),

 		newListCommand(dockerCli),

 		newRemoveCommand(dockerCli),

+		NewPruneCommand(dockerCli),

 	)

 	return cmd

 }

new file mode 100644

@@ -0,0 +1,72 @@

+package network

+

+import (

+	"fmt"

+

+	"golang.org/x/net/context"

+

+	"github.com/docker/docker/api/types"

+	"github.com/docker/docker/cli"

+	"github.com/docker/docker/cli/command"

+	"github.com/spf13/cobra"

+)

+

+type pruneOptions struct {

+	force bool

+}

+

+// NewPruneCommand returns a new cobra prune command for networks

+func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {

+	var opts pruneOptions

+

+	cmd := &cobra.Command{

+		Use:   "prune [OPTIONS]",

+		Short: "Remove all unused networks",

+		Args:  cli.NoArgs,

+		RunE: func(cmd *cobra.Command, args []string) error {

+			output, err := runPrune(dockerCli, opts)

+			if err != nil {

+				return err

+			}

+			if output != "" {

+				fmt.Fprintln(dockerCli.Out(), output)

+			}

+			return nil

+		},

+	}

+

+	flags := cmd.Flags()

+	flags.BoolVarP(&opts.force, "force", "f", false, "Do not prompt for confirmation")

+

+	return cmd

+}

+

+const warning = `WARNING! This will remove all networks not used by at least one container.

+Are you sure you want to continue?`

+

+func runPrune(dockerCli *command.DockerCli, opts pruneOptions) (output string, err error) {

+	if !opts.force && !command.PromptForConfirmation(dockerCli.In(), dockerCli.Out(), warning) {

+		return

+	}

+

+	report, err := dockerCli.Client().NetworksPrune(context.Background(), types.NetworksPruneConfig{})

+	if err != nil {

+		return

+	}

+

+	if len(report.NetworksDeleted) > 0 {

+		output = "Deleted Networks:\n"

+		for _, id := range report.NetworksDeleted {

+			output += id + "\n"

+		}

+	}

+

+	return

+}

+

+// RunPrune calls the Network Prune API

+// This returns the amount of space reclaimed and a detailed output string

+func RunPrune(dockerCli *command.DockerCli) (uint64, string, error) {

+	output, err := runPrune(dockerCli, pruneOptions{force: true})

+	return 0, output, err

+}

@@ -4,6 +4,7 @@ import (

 	"github.com/docker/docker/cli/command"

 	"github.com/docker/docker/cli/command/container"

 	"github.com/docker/docker/cli/command/image"

+	"github.com/docker/docker/cli/command/network"

 	"github.com/docker/docker/cli/command/volume"

 	"github.com/spf13/cobra"

 )

@@ -23,6 +24,11 @@ func NewImagePruneCommand(dockerCli *command.DockerCli) *cobra.Command {

 	return image.NewPruneCommand(dockerCli)

 }

+// NewNetworkPruneCommand returns a cobra prune command for Networks

+func NewNetworkPruneCommand(dockerCli *command.DockerCli) *cobra.Command {

+	return network.NewPruneCommand(dockerCli)

+}

+

 // RunContainerPrune executes a prune command for containers

 func RunContainerPrune(dockerCli *command.DockerCli) (uint64, string, error) {

 	return container.RunPrune(dockerCli)

@@ -37,3 +43,8 @@ func RunVolumePrune(dockerCli *command.DockerCli) (uint64, string, error) {

 func RunImagePrune(dockerCli *command.DockerCli, all bool) (uint64, string, error) {

 	return image.RunPrune(dockerCli, all)

 }

+

+// RunNetworkPrune executes a prune command for networks

+func RunNetworkPrune(dockerCli *command.DockerCli) (uint64, string, error) {

+	return network.RunPrune(dockerCli)

+}

@@ -39,6 +39,7 @@ const (

 	warning = `WARNING! This will remove:

 	- all stopped containers

 	- all volumes not used by at least one container

+	- all networks not used by at least one container

 	%s

 Are you sure you want to continue?`

@@ -64,13 +65,14 @@ func runPrune(dockerCli *command.DockerCli, opts pruneOptions) error {

 	for _, pruneFn := range []func(dockerCli *command.DockerCli) (uint64, string, error){

 		prune.RunContainerPrune,

 		prune.RunVolumePrune,

+		prune.RunNetworkPrune,

 	} {

 		spc, output, err := pruneFn(dockerCli)

 		if err != nil {

 			return err

 		}

-		if spc > 0 {

-			spaceReclaimed += spc

+		spaceReclaimed += spc

+		if output != "" {

 			fmt.Fprintln(dockerCli.Out(), output)

 		}

 	}

@@ -91,6 +91,7 @@ type NetworkAPIClient interface {

 	NetworkInspectWithRaw(ctx context.Context, networkID string) (types.NetworkResource, []byte, error)

 	NetworkList(ctx context.Context, options types.NetworkListOptions) ([]types.NetworkResource, error)

 	NetworkRemove(ctx context.Context, networkID string) error

+	NetworksPrune(ctx context.Context, cfg types.NetworksPruneConfig) (types.NetworksPruneReport, error)

 }

 // NodeAPIClient defines API client methods for the nodes

new file mode 100644

@@ -0,0 +1,26 @@

+package client

+

+import (

+	"encoding/json"

+	"fmt"

+

+	"github.com/docker/docker/api/types"

+	"golang.org/x/net/context"

+)

+

+// NetworksPrune requests the daemon to delete unused networks

+func (cli *Client) NetworksPrune(ctx context.Context, cfg types.NetworksPruneConfig) (types.NetworksPruneReport, error) {

+	var report types.NetworksPruneReport

+

+	serverResp, err := cli.post(ctx, "/networks/prune", nil, cfg, nil)

+	if err != nil {

+		return report, err

+	}

+	defer ensureReaderClosed(serverResp)

+

+	if err := json.NewDecoder(serverResp.body).Decode(&report); err != nil {

+		return report, fmt.Errorf("Error retrieving network prune report: %v", err)

+	}

+

+	return report, nil

+}

@@ -279,6 +279,7 @@ func (cli *DaemonCli) start(opts daemonOptions) (err error) {

 	// initMiddlewares needs cli.d to be populated. Dont change this init order.

 	cli.initMiddlewares(api, serverConfig)

+	d.SetCluster(c)

 	initRouter(api, d, c)

 	cli.setupConfigReloadTrap()

new file mode 100644

@@ -0,0 +1,12 @@

+package daemon

+

+import (

+	apitypes "github.com/docker/docker/api/types"

+)

+

+// Cluster is the interface for github.com/docker/docker/daemon/cluster.(*Cluster).

+type Cluster interface {

+	GetNetwork(input string) (apitypes.NetworkResource, error)

+	GetNetworks() ([]apitypes.NetworkResource, error)

+	RemoveNetwork(input string) error

+}

@@ -102,6 +102,7 @@ type Daemon struct {

 	containerdRemote          libcontainerd.Remote

 	defaultIsolation          containertypes.Isolation // Default isolation mode on Windows

 	clusterProvider           cluster.Provider

+	cluster                   Cluster

 }

 // HasExperimental returns whether the experimental features of the daemon are enabled or not

@@ -1234,3 +1235,13 @@ func copyBlkioEntry(entries []*containerd.BlkioStatsEntry) []types.BlkioStatEntr

 	}

 	return out

 }

+

+// GetCluster returns the cluster

+func (daemon *Daemon) GetCluster() Cluster {

+	return daemon.cluster

+}

+

+// SetCluster sets the cluster

+func (daemon *Daemon) SetCluster(cluster Cluster) {

+	daemon.cluster = cluster

+}

@@ -1,6 +1,8 @@

 package daemon

 import (

+	"regexp"

+

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/distribution/digest"

 	"github.com/docker/docker/api/types"

@@ -8,7 +10,9 @@ import (

 	"github.com/docker/docker/layer"

 	"github.com/docker/docker/pkg/directory"

 	"github.com/docker/docker/reference"

+	"github.com/docker/docker/runconfig"

 	"github.com/docker/docker/volume"

+	"github.com/docker/libnetwork"

 )

 // ContainersPrune removes unused containers

@@ -150,3 +154,72 @@ func (daemon *Daemon) ImagesPrune(config *types.ImagesPruneConfig) (*types.Image

 	return rep, nil

 }

+

+// localNetworksPrune removes unused local networks

+func (daemon *Daemon) localNetworksPrune(config *types.NetworksPruneConfig) (*types.NetworksPruneReport, error) {

+	rep := &types.NetworksPruneReport{}

+	var err error

+	// When the function returns true, the walk will stop.

+	l := func(nw libnetwork.Network) bool {

+		nwName := nw.Name()

+		predefined := runconfig.IsPreDefinedNetwork(nwName)

+		if !predefined && len(nw.Endpoints()) == 0 {

+			if err = daemon.DeleteNetwork(nw.ID()); err != nil {

+				logrus.Warnf("could not remove network %s: %v", nwName, err)

+				return false

+			}

+			rep.NetworksDeleted = append(rep.NetworksDeleted, nwName)

+		}

+		return false

+	}

+	daemon.netController.WalkNetworks(l)

+	return rep, err

+}

+

+// clusterNetworksPrune removes unused cluster networks

+func (daemon *Daemon) clusterNetworksPrune(config *types.NetworksPruneConfig) (*types.NetworksPruneReport, error) {

+	rep := &types.NetworksPruneReport{}

+	cluster := daemon.GetCluster()

+	networks, err := cluster.GetNetworks()

+	if err != nil {

+		return rep, err

+	}

+	networkIsInUse := regexp.MustCompile(`network ([[:alnum:]]+) is in use`)

+	for _, nw := range networks {

+		if nw.Name == "ingress" {

+			continue

+		}

+		// https://github.com/docker/docker/issues/24186

+		// `docker network inspect` unfortunately displays ONLY those containers that are local to that node.

+		// So we try to remove it anyway and check the error

+		err = cluster.RemoveNetwork(nw.ID)

+		if err != nil {

+			// we can safely ignore the "network .. is in use" error

+			match := networkIsInUse.FindStringSubmatch(err.Error())

+			if len(match) != 2 || match[1] != nw.ID {

+				logrus.Warnf("could not remove network %s: %v", nw.Name, err)

+			}

+			continue

+		}

+		rep.NetworksDeleted = append(rep.NetworksDeleted, nw.Name)

+	}

+	return rep, nil

+}

+

+// NetworksPrune removes unused networks

+func (daemon *Daemon) NetworksPrune(config *types.NetworksPruneConfig) (*types.NetworksPruneReport, error) {

+	rep := &types.NetworksPruneReport{}

+	clusterRep, err := daemon.clusterNetworksPrune(config)

+	if err != nil {

+		logrus.Warnf("could not remove cluster networks: %v", err)

+	} else {

+		rep.NetworksDeleted = append(rep.NetworksDeleted, clusterRep.NetworksDeleted...)

+	}

+	localRep, err := daemon.localNetworksPrune(config)

+	if err != nil {

+		logrus.Warnf("could not remove local networks: %v", err)

+	} else {

+		rep.NetworksDeleted = append(rep.NetworksDeleted, localRep.NetworksDeleted...)

+	}

+	return rep, err

+}

@@ -157,8 +157,10 @@ This section lists each version from latest to oldest.  Each listing includes a

 * `POST /containers/prune` prunes stopped containers.

 * `POST /images/prune` prunes unused images.

 * `POST /volumes/prune` prunes unused volumes.

+* `POST /networks/prune` prunes unused networks.

 * Every API response now includes a `Docker-Experimental` header specifying if experimental features are enabled (value can be `true` or `false`).

+

 ### v1.24 API changes

 [Docker Remote API v1.24](docker_remote_api_v1.24.md) documentation

@@ -3881,6 +3881,36 @@ Instruct the driver to remove the network (`id`).

 -   **404** - no such network

 -   **500** - server error

+### Prune unused networks

+

+`POST /networks/prune`

+

+Delete unused networks

+

+**Example request**:

+

+    POST /networks/prune HTTP/1.1

+    Content-Type: application/json

+

+    {

+    }

+

+**Example response**:

+

+    HTTP/1.1 200 OK

+    Content-Type: application/json

+

+    {

+        "NetworksDeleted": [

+            "n1"

+        ],

+    }

+

+**Status codes**:

+

+-   **200** – no error

+-   **500** – server error

+

 ## 3.6 Plugins

 ### List plugins

@@ -43,4 +43,5 @@ Total reclaimed space: 212 B

 * [system df](system_df.md)

 * [volume prune](volume_prune.md)

 * [image prune](image_prune.md)

+* [network prune](network_prune.md)

 * [system prune](system_prune.md)

@@ -67,4 +67,5 @@ Total reclaimed space: 16.43 MB

 * [system df](system_df.md)

 * [container prune](container_prune.md)

 * [volume prune](volume_prune.md)

+* [network prune](network_prune.md)

 * [system prune](system_prune.md)

@@ -98,5 +98,6 @@ You can connect a container to one or more networks. The networks need not be th

 * [network disconnect](network_disconnect.md)

 * [network ls](network_ls.md)

 * [network rm](network_rm.md)

+* [network prune](network_prune.md)

 * [Understand Docker container networks](https://docs.docker.com/engine/userguide/networking/)

 * [Work with networks](https://docs.docker.com/engine/userguide/networking/work-with-networks/)

@@ -197,4 +197,5 @@ to create an externally isolated `overlay` network, you can specify the

 * [network disconnect](network_disconnect.md)

 * [network ls](network_ls.md)

 * [network rm](network_rm.md)

+* [network prune](network_prune.md)

 * [Understand Docker container networks](https://docs.docker.com/engine/userguide/networking/)

@@ -39,4 +39,5 @@ Disconnects a container from a network. The container must be running to disconn

 * [network create](network_create.md)

 * [network ls](network_ls.md)

 * [network rm](network_rm.md)

+* [network prune](network_prune.md)

 * [Understand Docker container networks](https://docs.docker.com/engine/userguide/networking/)

@@ -128,4 +128,5 @@ $ docker network inspect simple-network

 * [network create](network_create.md)

 * [network ls](network_ls.md)

 * [network rm](network_rm.md)

+* [network prune](network_prune.md)

 * [Understand Docker container networks](https://docs.docker.com/engine/userguide/networking/)

@@ -214,4 +214,5 @@ d1584f8dc718: host

 * [network create](network_create.md)

 * [network inspect](network_inspect.md)

 * [network rm](network_rm.md)

+* [network prune](network_prune.md)

 * [Understand Docker container networks](https://docs.docker.com/engine/userguide/networking/)

new file mode 100644

@@ -0,0 +1,45 @@

+---

+title: "network prune"

+description: "Remove unused networks"

+keywords: [network, prune, delete]

+---

+

+# network prune

+

+```markdown

+Usage:	docker network prune [OPTIONS]

+

+Remove all unused networks

+

+Options:

+  -f, --force   Do not prompt for confirmation

+      --help    Print usage

+```

+

+Remove all unused networks. Unused networks are those which are not referenced by any containers.

+

+Example output:

+

+```bash

+$ docker network prune

+WARNING! This will remove all networks not used by at least one container.

+Are you sure you want to continue? [y/N] y

+Deleted Networks:

+n1

+n2

+```

+

+## Related information

+

+* [network disconnect ](network_disconnect.md)

+* [network connect](network_connect.md)

+* [network create](network_create.md)

+* [network ls](network_ls.md)

+* [network inspect](network_inspect.md)

+* [network rm](network_rm.md)

+* [Understand Docker container networks](../../userguide/networking/index.md)

+* [system df](system_df.md)

+* [container prune](container_prune.md)

+* [image prune](image_prune.md)

+* [volume prune](volume_prune.md)

+* [system prune](system_prune.md)

@@ -55,4 +55,5 @@ deletion.

 * [network create](network_create.md)

 * [network ls](network_ls.md)

 * [network inspect](network_inspect.md)

+* [network prune](network_prune.md)

 * [Understand Docker container networks](https://docs.docker.com/engine/userguide/networking/)

@@ -66,8 +66,11 @@ my-named-vol                                                       0

 * `UNIQUE SIZE` is the amount of space that is only used by a given image

 * `SIZE` is the virtual size of the image, it is the sum of `SHARED SIZE` and `UNIQUE SIZE`

+Note that network information is not shown because it doesn't consume the disk space.

+

 ## Related Information

 * [system prune](system_prune.md)

 * [container prune](container_prune.md)

 * [volume prune](volume_prune.md)

 * [image prune](image_prune.md)

+* [network prune](network_prune.md)

@@ -26,7 +26,7 @@ Options:

       --help    Print usage

 ```

-Remove all unused containers, volumes and images (both dangling and unreferenced).

+Remove all unused containers, volumes, networks and images (both dangling and unreferenced).

 Example output:

@@ -35,6 +35,7 @@ $ docker system prune -a

 WARNING! This will remove:

 	- all stopped containers

 	- all volumes not used by at least one container

+	- all networks not used by at least one container

 	- all images without at least one container associated to them

 Are you sure you want to continue? [y/N] y

 Deleted Containers:

@@ -74,4 +75,5 @@ Total reclaimed space: 13.5 MB

 * [system df](system_df.md)

 * [container prune](container_prune.md)

 * [image prune](image_prune.md)

+* [network prune](network_prune.md)

 * [system prune](system_prune.md)

@@ -50,4 +50,5 @@ Total reclaimed space: 36 B

 * [system df](system_df.md)

 * [container prune](container_prune.md)

 * [image prune](image_prune.md)

+* [network prune](network_prune.md)

 * [system prune](system_prune.md)

new file mode 100644

@@ -0,0 +1,61 @@

+// +build !windows

+

+package main

+

+import (

+	"strconv"

+	"strings"

+

+	"github.com/docker/docker/pkg/integration/checker"

+	"github.com/go-check/check"

+)

+

+func pruneNetworkAndVerify(c *check.C, d *SwarmDaemon, kept, pruned []string) {

+	_, err := d.Cmd("network", "prune", "--force")

+	c.Assert(err, checker.IsNil)

+	out, err := d.Cmd("network", "ls", "--format", "{{.Name}}")

+	c.Assert(err, checker.IsNil)

+	for _, s := range kept {

+		c.Assert(out, checker.Contains, s)

+	}

+	for _, s := range pruned {

+		c.Assert(out, checker.Not(checker.Contains), s)

+	}

+}

+

+func (s *DockerSwarmSuite) TestPruneNetwork(c *check.C) {

+	d := s.AddDaemon(c, true, true)

+	_, err := d.Cmd("network", "create", "n1") // used by container (testprune)

+	c.Assert(err, checker.IsNil)

+	_, err = d.Cmd("network", "create", "n2")

+	c.Assert(err, checker.IsNil)

+	_, err = d.Cmd("network", "create", "n3", "--driver", "overlay") // used by service (testprunesvc)

+	c.Assert(err, checker.IsNil)

+	_, err = d.Cmd("network", "create", "n4", "--driver", "overlay")

+	c.Assert(err, checker.IsNil)

+

+	cName := "testprune"

+	_, err = d.Cmd("run", "-d", "--name", cName, "--net", "n1", "busybox", "top")

+	c.Assert(err, checker.IsNil)

+

+	serviceName := "testprunesvc"

+	replicas := 1

+	out, err := d.Cmd("service", "create", "--name", serviceName,

+		"--replicas", strconv.Itoa(replicas),

+		"--network", "n3",

+		"busybox", "top")

+	c.Assert(err, checker.IsNil)

+	c.Assert(strings.TrimSpace(out), checker.Not(checker.Equals), "")

+	waitAndAssert(c, defaultReconciliationTimeout, d.checkActiveContainerCount, checker.Equals, replicas+1)

+

+	// prune and verify

+	pruneNetworkAndVerify(c, d, []string{"n1", "n3"}, []string{"n2", "n4"})

+

+	// remove containers, then prune and verify again

+	_, err = d.Cmd("rm", "-f", cName)

+	c.Assert(err, checker.IsNil)

+	_, err = d.Cmd("service", "rm", serviceName)

+	c.Assert(err, checker.IsNil)

+	waitAndAssert(c, defaultReconciliationTimeout, d.checkActiveContainerCount, checker.Equals, 0)

+	pruneNetworkAndVerify(c, d, []string{}, []string{"n1", "n3"})

+}