Remove initialization of swarm but display useful error

container/container.go

@@ -2,6 +2,7 @@ package container
 
 import (
 	"context"
+	"errors"
 	"io"
 	"time"
 
@@ -66,7 +67,7 @@ func New(options ...Option) (*DockerContainer, error) {
 		}
 	}
 	c.negotiateAPIVersion()
-	if err := c.createSwarmIfNeeded(); err != nil {
+	if err := c.checkSwarm(); err != nil {
 		return c, err
 	}
 	return c, c.createSharedNetworkIfNeeded()
@@ -92,22 +93,17 @@ func (c *DockerContainer) negotiateAPIVersion() {
 	c.client.NegotiateAPIVersion(ctx)
 }
 
-func (c *DockerContainer) createSwarmIfNeeded() error {
+func (c *DockerContainer) checkSwarm() error {
 	ctx, cancel := context.WithTimeout(context.Background(), c.callTimeout)
 	defer cancel()
 	info, err := c.client.Info(ctx)
 	if err != nil {
 		return err
 	}
-	if info.Swarm.NodeID != "" {
-		return nil
+	if info.Swarm.NodeID == "" {
+		return errors.New("docker swarm is not initialized. Execute \"docker swarm init\" and try again")
 	}
-	ctx, cancel = context.WithTimeout(context.Background(), c.callTimeout)
-	defer cancel()
-	_, err = c.client.SwarmInit(ctx, swarm.InitRequest{
-		ListenAddr: "0.0.0.0:2377", // https://docs.docker.com/engine/reference/commandline/swarm_init/#usage
-	})
-	return err
+	return nil
 }
 
 // FindContainer returns a docker container.

container/container_integration_test.go

@@ -8,12 +8,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestIntegrationCreateSwarmIfNeeded(t *testing.T) {
-	c, err := New()
-	require.NoError(t, err)
-	require.Nil(t, c.createSwarmIfNeeded())
-}
-
 func TestIntegrationFindContainerNotExisting(t *testing.T) {
 	c, err := New()
 	require.NoError(t, err)

container/container_test.go

@@ -80,8 +80,6 @@ func TestNew(t *testing.T) {
 		t.Error("should fetch info")
 	}
 
-	require.Equal(t, "0.0.0.0:2377", (<-dt.LastSwarmInit()).Request.ListenAddr)
-
 	ln := <-dt.LastNetworkCreate()
 	require.Equal(t, cfg.Core.Name, ln.Name)
 	require.Equal(t, types.NetworkCreate{

container/dockertest/client.go

@@ -163,7 +163,7 @@ func (c *Client) Info(context.Context) (types.Info, error) {
 	case resp := <-c.responses.info:
 		return resp.info, resp.err
 	default:
-		return types.Info{}, nil
+		return types.Info{Swarm: swarm.Info{NodeID: "1"}}, nil
 	}
 }