Restore error type in FindNetwork

The error type libnetwork.ErrNoSuchNetwork is used in the controller
to retry the network creation as a managed network though the manager.
The change of the type was breaking the logic causing the network to
not being created anymore so that no new container on that network
was able to be launched
Added unit test

Signed-off-by: Flavio Crisciani <flavio.crisciani@docker.com>

daemon/cluster/executor/container/controller.go

@@ -183,7 +183,7 @@ func (r *controller) Start(ctx context.Context) error {
 
 	for {
 		if err := r.adapter.start(ctx); err != nil {
-			if _, ok := err.(libnetwork.ErrNoSuchNetwork); ok {
+			if _, ok := errors.Cause(err).(libnetwork.ErrNoSuchNetwork); ok {
 				// Retry network creation again if we
 				// failed because some of the networks
 				// were not found.

daemon/daemon_test.go

@@ -7,6 +7,7 @@ import (
 	"runtime"
 	"testing"
 
+	"github.com/docker/docker/api/errdefs"
 	containertypes "github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/container"
 	_ "github.com/docker/docker/pkg/discovery/memory"
@@ -17,6 +18,8 @@ import (
 	"github.com/docker/docker/volume/local"
 	"github.com/docker/docker/volume/store"
 	"github.com/docker/go-connections/nat"
+	"github.com/docker/libnetwork"
+	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -311,3 +314,12 @@ func TestValidateContainerIsolation(t *testing.T) {
 	_, err := d.verifyContainerSettings(runtime.GOOS, &containertypes.HostConfig{Isolation: containertypes.Isolation("invalid")}, nil, false)
 	assert.EqualError(t, err, "invalid isolation 'invalid' on "+runtime.GOOS)
 }
+
+func TestFindNetworkErrorType(t *testing.T) {
+	d := Daemon{}
+	_, err := d.FindNetwork("fakeNet")
+	_, ok := errors.Cause(err).(libnetwork.ErrNoSuchNetwork)
+	if !errdefs.IsNotFound(err) || !ok {
+		assert.Fail(t, "The FindNetwork method MUST always return an error that implements the NotFound interface and is ErrNoSuchNetwork")
+	}
+}

daemon/errors.go

@@ -21,10 +21,6 @@ func volumeNotFound(id string) error {
 	return objNotFoundError{"volume", id}
 }
 
-func networkNotFound(id string) error {
-	return objNotFoundError{"network", id}
-}
-
 type objNotFoundError struct {
 	object string
 	id     string
@@ -230,3 +226,20 @@ func translateContainerdStartErr(cmd string, setExitCode func(int), err error) e
 	// TODO: it would be nice to get some better errors from containerd so we can return better errors here
 	return retErr
 }
+
+// TODO: cpuguy83 take care of it once the new library is ready
+type errNotFound struct{ error }
+
+func (errNotFound) NotFound() {}
+
+func (e errNotFound) Cause() error {
+	return e.error
+}
+
+// notFound is a helper to create an error of the class with the same name from any error type
+func notFound(err error) error {
+	if err == nil {
+		return nil
+	}
+	return errNotFound{err}
+}

daemon/network.go

@@ -45,7 +45,9 @@ func (daemon *Daemon) FindNetwork(idName string) (libnetwork.Network, error) {
 	// 3. match by ID prefix
 	list := daemon.GetNetworksByIDPrefix(idName)
 	if len(list) == 0 {
-		return nil, errors.WithStack(networkNotFound(idName))
+		// Be very careful to change the error type here, the libnetwork.ErrNoSuchNetwork error is used by the controller
+		// to retry the creation of the network as managed through the swarm manager
+		return nil, errors.WithStack(notFound(libnetwork.ErrNoSuchNetwork(idName)))
 	}
 	if len(list) > 1 {
 		return nil, errors.WithStack(invalidIdentifier(idName))

integration-cli/docker_cli_netmode_test.go

@@ -49,7 +49,7 @@ func (s *DockerSuite) TestNetHostname(c *check.C) {
 	c.Assert(out, checker.Contains, "Invalid network mode: invalid container format container:<name|id>")
 
 	out, _ = dockerCmdWithFail(c, "run", "--net=weird", "busybox", "ps")
-	c.Assert(strings.ToLower(out), checker.Contains, "no such network")
+	c.Assert(strings.ToLower(out), checker.Contains, "not found")
 }
 
 func (s *DockerSuite) TestConflictContainerNetworkAndLinks(c *check.C) {