api: allow creating a network of which name is the prefix of the ID o…

…f a swarm network

Previously, it doesn't allow creating such a network:

e.g.

    $ docker network inspect -f '{{.Id}}' ingress
    84xh9knigj6zyt00u31e26nj3
    $ docker network create 84
    Error response from daemon: network with name 84 already exists

Fix #27866

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

api/server/router/network/network_routes.go

@@ -3,6 +3,7 @@ package network
 import (
 	"encoding/json"
 	"net/http"
+	"strings"
 
 	"golang.org/x/net/context"
 
@@ -79,8 +80,16 @@ func (n *networkRouter) postNetworkCreate(ctx context.Context, w http.ResponseWr
 		return err
 	}
 
-	if _, err := n.clusterProvider.GetNetwork(create.Name); err == nil {
-		return libnetwork.NetworkNameError(create.Name)
+	if nw, err := n.clusterProvider.GetNetwork(create.Name); err == nil {
+		// GetNetwork can return nw if:
+		//  1. nw.Name == create.Name
+		//  2. nw.ID == create.Name
+		//  3. nw.ID starts with create.Name
+		//
+		// we do not need to raise an error for the case 3.
+		if !strings.HasPrefix(nw.ID, create.Name) {
+			return libnetwork.NetworkNameError(create.Name)
+		}
 	}
 
 	nw, err := n.backend.CreateNetwork(create)

integration-cli/docker_cli_swarm_test.go

@@ -588,3 +588,21 @@ func (s *DockerSwarmSuite) TestSwarmServiceEnvFile(c *check.C) {
 	c.Assert(err, checker.IsNil)
 	c.Assert(out, checker.Contains, "[VAR1=C VAR2]")
 }
+
+// Test case for #27866
+func (s *DockerSwarmSuite) TestSwarmNetworkCreateIssue27866(c *check.C) {
+	d := s.AddDaemon(c, true, true)
+	out, err := d.Cmd("network", "inspect", "-f", "{{.Id}}", "ingress")
+	c.Assert(err, checker.IsNil, check.Commentf("out: %v", out))
+	ingressID := strings.TrimSpace(out)
+	c.Assert(ingressID, checker.Not(checker.Equals), "")
+
+	// create a network of which name is the prefix of the ID of an overlay network
+	// (ingressID in this case)
+	newNetName := ingressID[0:2]
+	out, err = d.Cmd("network", "create", "--driver", "overlay", newNetName)
+	// In #27866, it was failing because of "network with name %s already exists"
+	c.Assert(err, checker.IsNil, check.Commentf("out: %v", out))
+	out, err = d.Cmd("network", "rm", newNetName)
+	c.Assert(err, checker.IsNil, check.Commentf("out: %v", out))
+}