Merge pull request #82 from mutagen-io/no-network-dep-fix

sidecar: disable networking if no network dependencies are present

pkg/mutagen/liaison.go

@@ -464,6 +464,13 @@ func (l *Liaison) processProject(project *types.Project) error {
 	}
 	composeVersion := strings.TrimPrefix(versions.Compose, "v")
 
+	// If there are no network dependencies, then disable networking.
+	var networkMode string
+	if len(networkDependencies) == 0 {
+		networkMode = "none"
+		networkDependencies = nil
+	}
+
 	// Create and record the Mutagen sidecar service definition. The service
 	// configuration we generate here needs to match (as closely as possible)
 	// those generated by projectOptions.toProject in Compose. In particular,
@@ -476,9 +483,10 @@ func (l *Liaison) processProject(project *types.Project) error {
 			sidecarRoleLabelKey:    sidecarRoleLabelValue,
 			sidecarVersionLabelKey: mutagen.Version,
 		},
-		Networks: networkDependencies,
-		Volumes:  serviceVolumeDependencies,
-		CapAdd:   capabilities,
+		NetworkMode: networkMode,
+		Networks:    networkDependencies,
+		Volumes:     serviceVolumeDependencies,
+		CapAdd:      capabilities,
 		CustomLabels: types.Labels{
 			api.ProjectLabel:     project.Name,
 			api.ServiceLabel:     sidecarServiceName,