Add "orchard run" command

It starts a proxy to an Orchard host, then runs a local command
with the DOCKER_HOST envvar set.

Signed-off-by: Ben Firshman <[email protected]>

commands/commands.go

@@ -57,6 +57,7 @@ var All = []*Command{
 	Hosts,
 	IP,
 	Proxy,
+	Run,
 }
 
 var HostSubcommands = []*Command{
@@ -71,6 +72,7 @@ func init() {
 	Docker.Run = RunDocker
 	Proxy.Run = RunProxy
 	IP.Run = RunIP
+	Run.Run = RunRun
 }
 
 var Hosts = &Command{
@@ -165,6 +167,23 @@ host (named 'default') will be assumed.
 `,
 }
 
+var Run = &Command{
+	UsageLine: "run [-H HOST] COMMAND [ARGS...]",
+	Short:     "Run a command with the DOCKER_HOST envvar set",
+	Long: `Start a proxy to an Orchard host and run a command locally
+with the DOCKER_HOST environment variable set.
+
+For example:
+
+$ orchard run fig up
+
+You can optionally specify which host - if you don't, the default
+host (named 'default') will be assumed.
+`,
+}
+
+var flRunHost = Run.Flag.String("H", "", "")
+
 func RunHosts(cmd *Command, args []string) error {
 	list := len(args) == 0 || (len(args) == 1 && args[0] == "ls")
 
@@ -331,6 +350,21 @@ func RunIP(cmd *Command, args []string) error {
 	return nil
 }
 
+func RunRun(cmd *Command, args []string) error {
+	if len(args) < 1 {
+		return cmd.UsageError("`orchard run` expects at least 1 argument")
+	}
+	return WithDockerProxy("", *flRunHost, func(listenURL string) error {
+		os.Setenv("DOCKER_HOST", listenURL)
+
+		cmd := exec.Command(args[0], args[1:]...)
+		cmd.Stdin = os.Stdin
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		return cmd.Run()
+	})
+}
+
 func WithDockerProxy(listenURL, hostName string, callback func(string) error) error {
 	if hostName == "" {
 		hostName = "default"