always add short container id as net alias

This matches what docker does. Also make sure the net aliases are also
shown when the container is stopped.

docker-compose uses this special alias entry to check if it is already
correctly connected to the network. [1]
Because we do not support static ips on network connect at the moment
calling disconnect && connect will loose the static ip.

Fixes containers#11748

[1] https://github.com/docker/compose/blob/0bea52b18dda3de8c28fcfb0c80cc08b8950645e/compose/service.py#L663-L667

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

libpod/container_internal_linux.go

@@ -1310,7 +1310,7 @@ func (c *Container) restore(ctx context.Context, options ContainerCheckpointOpti
 	if err == nil && options.Name == "" && (!options.IgnoreStaticIP || !options.IgnoreStaticMAC) {
 		// The file with the network.status does exist. Let's restore the
 		// container with the same networks settings as during checkpointing.
-		aliases, err := c.runtime.state.GetAllNetworkAliases(c)
+		aliases, err := c.GetAllNetworkAliases()
 		if err != nil {
 			return err
 		}

libpod/networking_linux.go

@@ -48,6 +48,55 @@ const (
 	persistentCNIDir = "/var/lib/cni"
 )
 
+// GetAllNetworkAliases returns all configured aliases for this container.
+// It also adds the container short ID as alias to match docker.
+func (c *Container) GetAllNetworkAliases() (map[string][]string, error) {
+	allAliases, err := c.runtime.state.GetAllNetworkAliases(c)
+	if err != nil {
+		return nil, err
+	}
+
+	// get the all attached networks, we cannot use GetAllNetworkAliases()
+	// since it returns nil if there are no aliases
+	nets, _, err := c.networks()
+	if err != nil {
+		return nil, err
+	}
+
+	// add container short ID as alias to match docker
+	for _, net := range nets {
+		network, err := c.runtime.network.NetworkInspect(net)
+		if err != nil {
+			return nil, err
+		}
+		// only add alias if dns is enabled for this network
+		if network.DNSEnabled {
+			allAliases[net] = append(allAliases[net], c.config.ID[:12])
+		}
+	}
+	return allAliases, nil
+}
+
+// GetNetworkAliases returns configured aliases for this network.
+// It also adds the container short ID as alias to match docker.
+func (c *Container) GetNetworkAliases(netName string) ([]string, error) {
+	aliases, err := c.runtime.state.GetNetworkAliases(c, netName)
+	if err != nil {
+		return nil, err
+	}
+
+	// add container short ID as alias to match docker
+	network, err := c.runtime.network.NetworkInspect(netName)
+	if err != nil {
+		return nil, err
+	}
+	// only add alias if dns is enabled for this network
+	if network.DNSEnabled {
+		aliases = append(aliases, c.config.ID[:12])
+	}
+	return aliases, nil
+}
+
 func (c *Container) getNetworkOptions() (types.NetworkOptions, error) {
 	opts := types.NetworkOptions{
 		ContainerID:   c.config.ID,
@@ -61,7 +110,7 @@ func (c *Container) getNetworkOptions() (types.NetworkOptions, error) {
 	if err != nil {
 		return opts, err
 	}
-	aliases, err := c.runtime.state.GetAllNetworkAliases(c)
+	aliases, err := c.GetAllNetworkAliases()
 	if err != nil {
 		return opts, err
 	}
@@ -872,7 +921,7 @@ func (r *Runtime) reloadContainerNetwork(ctr *Container) (map[string]types.Statu
 		}
 	}
 
-	aliases, err := ctr.runtime.state.GetAllNetworkAliases(ctr)
+	aliases, err := ctr.GetAllNetworkAliases()
 	if err != nil {
 		return nil, err
 	}
@@ -975,6 +1024,11 @@ func (c *Container) getContainerNetworkInfo() (*define.InspectNetworkSettings, e
 			for _, net := range networks {
 				cniNet := new(define.InspectAdditionalNetwork)
 				cniNet.NetworkID = net
+				aliases, err := c.GetNetworkAliases(net)
+				if err != nil {
+					return nil, err
+				}
+				cniNet.Aliases = aliases
 				settings.Networks[net] = cniNet
 			}
 		}
@@ -1009,7 +1063,7 @@ func (c *Container) getContainerNetworkInfo() (*define.InspectNetworkSettings, e
 				return nil, err
 			}
 
-			aliases, err := c.runtime.state.GetNetworkAliases(c, name)
+			aliases, err := c.GetNetworkAliases(name)
 			if err != nil {
 				return nil, err
 			}
@@ -1253,6 +1307,7 @@ func (c *Container) NetworkConnect(nameOrID, netName string, aliases []string) e
 	if !exists {
 		return errors.Errorf("no network interface name for container %s on network %s", c.config.ID, netName)
 	}
+	aliases = append(aliases, c.config.ID[:12])
 	opts.Networks = map[string]types.PerNetworkOptions{
 		netName: {
 			Aliases:       aliases,

test/e2e/network_connect_disconnect_test.go

@@ -52,7 +52,6 @@ var _ = Describe("Podman network connect and disconnect", func() {
 	})
 
 	It("network disconnect with net mode slirp4netns should result in error", func() {
-		SkipIfRootless("network connect and disconnect are only rootful")
 		netName := "slirp" + stringid.GenerateNonCryptoID()
 		session := podmanTest.Podman([]string{"network", "create", netName})
 		session.WaitWithDefaultTimeout()
@@ -118,7 +117,6 @@ var _ = Describe("Podman network connect and disconnect", func() {
 	})
 
 	It("network connect with net mode slirp4netns should result in error", func() {
-		SkipIfRootless("network connect and disconnect are only rootful")
 		netName := "slirp" + stringid.GenerateNonCryptoID()
 		session := podmanTest.Podman([]string{"network", "create", netName})
 		session.WaitWithDefaultTimeout()
@@ -146,14 +144,20 @@ var _ = Describe("Podman network connect and disconnect", func() {
 		ctr := podmanTest.Podman([]string{"create", "--name", "test", "--network", netName, ALPINE, "top"})
 		ctr.WaitWithDefaultTimeout()
 		Expect(ctr).Should(Exit(0))
+		cid := session.OutputToString()
+
+		// network alias container short id is always added and shown in inspect
+		inspect := podmanTest.Podman([]string{"container", "inspect", "test", "--format", "{{(index .NetworkSettings.Networks \"" + netName + "\").Aliases}}"})
+		inspect.WaitWithDefaultTimeout()
+		Expect(inspect).Should(Exit(0))
+		Expect(inspect.OutputToString()).To(Equal("[" + cid[0:12] + "]"))
 
 		con := podmanTest.Podman([]string{"network", "connect", netName, "test"})
 		con.WaitWithDefaultTimeout()
 		Expect(con).Should(ExitWithError())
 	})
 
 	It("podman network connect", func() {
-		SkipIfRemote("This requires a pending PR to be merged before it will work")
 		netName := "aliasTest" + stringid.GenerateNonCryptoID()
 		session := podmanTest.Podman([]string{"network", "create", netName})
 		session.WaitWithDefaultTimeout()
@@ -163,6 +167,7 @@ var _ = Describe("Podman network connect and disconnect", func() {
 		ctr := podmanTest.Podman([]string{"run", "-dt", "--name", "test", "--network", netName, ALPINE, "top"})
 		ctr.WaitWithDefaultTimeout()
 		Expect(ctr).Should(Exit(0))
+		cid := session.OutputToString()
 
 		exec := podmanTest.Podman([]string{"exec", "-it", "test", "ip", "addr", "show", "eth0"})
 		exec.WaitWithDefaultTimeout()
@@ -184,6 +189,12 @@ var _ = Describe("Podman network connect and disconnect", func() {
 		Expect(inspect).Should(Exit(0))
 		Expect(inspect.OutputToString()).To(Equal("2"))
 
+		// network alias container short id is always added and shown in inspect
+		inspect = podmanTest.Podman([]string{"container", "inspect", "test", "--format", "{{(index .NetworkSettings.Networks \"" + newNetName + "\").Aliases}}"})
+		inspect.WaitWithDefaultTimeout()
+		Expect(inspect).Should(Exit(0))
+		Expect(inspect.OutputToString()).To(Equal("[" + cid[0:12] + "]"))
+
 		exec = podmanTest.Podman([]string{"exec", "-it", "test", "ip", "addr", "show", "eth1"})
 		exec.WaitWithDefaultTimeout()
 		Expect(exec).Should(Exit(0))
@@ -193,7 +204,6 @@ var _ = Describe("Podman network connect and disconnect", func() {
 		rm.WaitWithDefaultTimeout()
 		Expect(rm).Should(Exit(0))
 		Expect(rm.ErrorToString()).To(Equal(""))
-
 	})
 
 	It("podman network connect when not running", func() {

test/system/500-networking.bats

@@ -415,6 +415,10 @@ load helpers
     run_podman inspect $cid --format "{{(index .NetworkSettings.Networks \"$netname\").MacAddress}}"
     mac="$output"
 
+    # check network alias for container short id
+    run_podman inspect $cid --format "{{(index .NetworkSettings.Networks \"$netname\").Aliases}}"
+    is "$output" "[${cid:0:12}]" "short container id in network aliases"
+
     run_podman network disconnect $netname $cid
 
     # check that we cannot curl (timeout after 3 sec)
@@ -443,6 +447,10 @@ load helpers
     # connect a second network
     run_podman network connect $netname2 $cid
 
+    # check network2 alias for container short id
+    run_podman inspect $cid --format "{{(index .NetworkSettings.Networks \"$netname2\").Aliases}}"
+    is "$output" "[${cid:0:12}]" "short container id in network aliases"
+
     # curl should work
     run curl --max-time 3 -s $SERVER/index.txt
     is "$output" "$random_1" "curl 127.0.0.1:/index.txt should work"