Supporting proxied Docker APIs through DOCKER_HOST (#70)

README.md

@@ -80,7 +80,8 @@ services:
       - data:/backup/my-app-backup:ro
       # Mounting the Docker socket allows the script to stop and restart
       # the container during backup. You can omit this if you don't want
-      # to stop the container
+      # to stop the container. In case you need to proxy the socket, you can
+      # also provide a location by setting `DOCKER_HOST` in the container
       - /var/run/docker.sock:/var/run/docker.sock:ro
       # If you mount a local directory or volume to `/archive` a local
       # copy of the backup will be stored there. You can override the

cmd/backup/script.go

@@ -90,7 +90,8 @@ func newScript() (*script, error) {
 	s.file = timeutil.Strftime(&s.stats.StartTime, s.file)
 
 	_, err := os.Stat("/var/run/docker.sock")
-	if !os.IsNotExist(err) {
+	_, dockerHostSet := os.LookupEnv("DOCKER_HOST")
+	if !os.IsNotExist(err) || dockerHostSet {
 		cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
 		if err != nil {
 			return nil, fmt.Errorf("newScript: failed to create docker client")