17840: Deduplicate flag-parsing code.

[arvados.git] / cmd / arvados-client / container_gateway.go

diff --git a/cmd/arvados-client/container_gateway.go b/cmd/arvados-client/container_gateway.go
index 6dbc241bca3cb7252f8488a8c061bb43a94aa3c1..aca6c5b797fa4ec3b036ee8300ae3f4fcbe5e885 100644 (file)
--- a/cmd/arvados-client/container_gateway.go
+++ b/cmd/arvados-client/container_gateway.go
@@ -13,9 +13,11 @@ import (
        "net/url"
        "os"
        "os/exec"
+       "path/filepath"
        "strings"
        "syscall"
 
+       "git.arvados.org/arvados.git/lib/cmd"
        "git.arvados.org/arvados.git/lib/controller/rpc"
        "git.arvados.org/arvados.git/sdk/go/arvados"
 )
@@ -26,25 +28,11 @@ type shellCommand struct{}
 
 func (shellCommand) RunCommand(prog string, args []string, stdin io.Reader, stdout, stderr io.Writer) int {
        f := flag.NewFlagSet(prog, flag.ContinueOnError)
-       f.SetOutput(stderr)
-       f.Usage = func() {
-               fmt.Fprint(stderr, prog+`: open an interactive shell on a running container.
-
-Usage: `+prog+` [options] [username@]container-uuid [ssh-options] [remote-command [args...]]
-
-Options:
-`)
-               f.PrintDefaults()
-       }
        detachKeys := f.String("detach-keys", "ctrl-],ctrl-]", "set detach key sequence, as in docker-attach(1)")
-       err := f.Parse(args)
-       if err != nil {
-               fmt.Fprintln(stderr, err)
-               return 2
-       }
-
-       if f.NArg() < 1 {
-               f.Usage()
+       if ok, code := cmd.ParseFlags(f, prog, args, "[username@]container-uuid [ssh-options] [remote-command [args...]]", stderr); !ok {
+               return code
+       } else if f.NArg() < 1 {
+               fmt.Fprintf(stderr, "missing required argument: container-uuid (try -help)\n")
                return 2
        }
        target := f.Args()[0]
@@ -65,13 +53,19 @@ Options:
        // kex_exchange_identification: Connection closed by remote host
        // Connection closed by UNKNOWN port 65535
        // exit status 255
+       //
+       // In case our target is a container request, the probe also
+       // resolves it to a container, so we don't connect to two
+       // different containers in a race.
+       var probetarget bytes.Buffer
        exitcode := connectSSHCommand{}.RunCommand(
                "arvados-client connect-ssh",
                []string{"-detach-keys=" + *detachKeys, "-probe-only=true", target},
-               &bytes.Buffer{}, &bytes.Buffer{}, stderr)
+               &bytes.Buffer{}, &probetarget, stderr)
        if exitcode != 0 {
                return exitcode
        }
+       target = strings.Trim(probetarget.String(), "\n")
 
        selfbin, err := os.Readlink("/proc/self/exe")
        if err != nil {
@@ -105,21 +99,24 @@ func (connectSSHCommand) RunCommand(prog string, args []string, stdin io.Reader,
        f := flag.NewFlagSet(prog, flag.ContinueOnError)
        f.SetOutput(stderr)
        f.Usage = func() {
+               _, prog := filepath.Split(prog)
                fmt.Fprint(stderr, prog+`: connect to the gateway service for a running container.
 
+NOTE: You almost certainly don't want to use this command directly. It
+is meant to be used internally. Use "arvados-client shell" instead.
+
 Usage: `+prog+` [options] [username@]container-uuid
 
 Options:
 `)
                f.PrintDefaults()
        }
-       probeOnly := f.Bool("probe-only", false, "do not transfer IO, just exit 0 immediately if tunnel setup succeeds")
+       probeOnly := f.Bool("probe-only", false, "do not transfer IO, just setup tunnel, print target UUID, and exit")
        detachKeys := f.String("detach-keys", "", "set detach key sequence, as in docker-attach(1)")
-       if err := f.Parse(args); err != nil {
-               fmt.Fprintln(stderr, err)
-               return 2
+       if ok, code := cmd.ParseFlags(f, prog, args, "[username@]container-uuid", stderr); !ok {
+               return code
        } else if f.NArg() != 1 {
-               f.Usage()
+               fmt.Fprintf(stderr, "missing required argument: [username@]container-uuid\n")
                return 2
        }
        targetUUID := f.Args()[0]
@@ -175,6 +172,7 @@ Options:
        defer sshconn.Conn.Close()
 
        if *probeOnly {
+               fmt.Fprintln(stdout, targetUUID)
                return 0
        }