refactor!: consolidate SSH handling

Closes coop-cloud/organising#389.
Closes coop-cloud/organising#341.
Closes coop-cloud/organising#326.
Closes coop-cloud/organising#380.
Closes coop-cloud/organising#360.

pkg/client/client.go

@@ -2,22 +2,29 @@
 package client
 
 import (
+	"context"
+	"errors"
+	"fmt"
 	"net/http"
 	"os"
 	"time"
 
 	contextPkg "coopcloud.tech/abra/pkg/context"
+	sshPkg "coopcloud.tech/abra/pkg/ssh"
 	commandconnPkg "coopcloud.tech/abra/pkg/upstream/commandconn"
 	"github.com/docker/docker/client"
 	"github.com/sirupsen/logrus"
 )
 
-// New initiates a new Docker client.
-func New(contextName string) (*client.Client, error) {
+// New initiates a new Docker client. New client connections are validated so
+// that we ensure connections via SSH to the daemon can succeed. It takes into
+// account that you may only want the local client and not communicate via SSH.
+// For this use-case, please pass "default" as the contextName.
+func New(serverName string) (*client.Client, error) {
 	var clientOpts []client.Opt
 
-	if contextName != "default" {
-		context, err := GetContext(contextName)
+	if serverName != "default" {
+		context, err := GetContext(serverName)
 		if err != nil {
 			return nil, err
 		}
@@ -33,7 +40,6 @@ func New(contextName string) (*client.Client, error) {
 		}
 
 		httpClient := &http.Client{
-			// No tls, no proxy
 			Transport: &http.Transport{
 				DialContext:     helper.Dialer,
 				IdleConnTimeout: 30 * time.Second,
@@ -59,7 +65,20 @@ func New(contextName string) (*client.Client, error) {
 		return nil, err
 	}
 
-	logrus.Debugf("created client for %s", contextName)
+	logrus.Debugf("created client for %s", serverName)
+
+	info, err := cl.Info(context.Background())
+	if err != nil {
+		return cl, sshPkg.Fatal(serverName, err)
+	}
+
+	if info.Swarm.LocalNodeState == "inactive" {
+		if serverName != "default" {
+			return cl, fmt.Errorf("swarm mode not enabled on %s?", serverName)
+		} else {
+			return cl, errors.New("swarm mode not enabled on local server?")
+		}
+	}
 
 	return cl, nil
 }

pkg/client/secret.go

@@ -4,20 +4,14 @@ import (
 	"context"
 
 	"github.com/docker/docker/api/types/swarm"
+	"github.com/docker/docker/client"
 )
 
-func StoreSecret(secretName, secretValue, server string) error {
-	cl, err := New(server)
-	if err != nil {
-		return err
-	}
-
-	ctx := context.Background()
+func StoreSecret(cl *client.Client, secretName, secretValue, server string) error {
 	ann := swarm.Annotations{Name: secretName}
 	spec := swarm.SecretSpec{Annotations: ann, Data: []byte(secretValue)}
 
-	// We don't bother with the secret IDs for now
-	if _, err := cl.SecretCreate(ctx, spec); err != nil {
+	if _, err := cl.SecretCreate(context.Background(), spec); err != nil {
 		return err
 	}
 

pkg/client/volumes.go

@@ -5,14 +5,10 @@ import (
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/client"
 )
 
-func GetVolumes(ctx context.Context, server string, fs filters.Args) ([]*types.Volume, error) {
-	cl, err := New(server)
-	if err != nil {
-		return nil, err
-	}
-
+func GetVolumes(cl *client.Client, ctx context.Context, server string, fs filters.Args) ([]*types.Volume, error) {
 	volumeListOKBody, err := cl.VolumeList(ctx, fs)
 	volumeList := volumeListOKBody.Volumes
 	if err != nil {
@@ -32,12 +28,7 @@ func GetVolumeNames(volumes []*types.Volume) []string {
 	return volumeNames
 }
 
-func RemoveVolumes(ctx context.Context, server string, volumeNames []string, force bool) error {
-	cl, err := New(server)
-	if err != nil {
-		return err
-	}
-
+func RemoveVolumes(cl *client.Client, ctx context.Context, server string, volumeNames []string, force bool) error {
 	for _, volName := range volumeNames {
 		err := cl.VolumeRemove(ctx, volName, force)
 		if err != nil {