implement exec

Resolves #593

Signed-off-by: Tomas Tomecek <ttomecek@redhat.com>

compose/cli/docopt_command.py

@@ -43,6 +43,10 @@ class DocoptCommand(object):
 
     def get_handler(self, command):
         command = command.replace('-', '_')
+        # we certainly want to have "exec" command, since that's what docker client has
+        # but in python exec is a keyword
+        if command == "exec":
+            command = "exec_command"
 
         if not hasattr(self, command):
             raise NoSuchCommand(command, self)

compose/cli/main.py

@@ -43,7 +43,7 @@ from .utils import yesno
 
 
 if not IS_WINDOWS_PLATFORM:
-    from dockerpty.pty import PseudoTerminal, RunOperation
+    from dockerpty.pty import PseudoTerminal, RunOperation, ExecOperation
 
 log = logging.getLogger(__name__)
 console_handler = logging.StreamHandler(sys.stderr)
@@ -152,6 +152,7 @@ class TopLevelCommand(DocoptCommand):
       create             Create services
       down               Stop and remove containers, networks, images, and volumes
       events             Receive real time events from containers
+      exec               Execute a command in a running container
       help               Get help on a command
       kill               Kill containers
       logs               View output from containers
@@ -298,6 +299,57 @@ class TopLevelCommand(DocoptCommand):
             print(formatter(event))
             sys.stdout.flush()
 
+    def exec_command(self, project, options):
+        """
+        Execute a command in a running container
+
+        Usage: exec [options] SERVICE COMMAND [ARGS...]
+
+        Options:
+            -d                Detached mode: Run command in the background.
+            --privileged      Give extended privileges to the process.
+            --user USER       Run the command as this user.
+            -T                Disable pseudo-tty allocation. By default `docker-compose exec`
+                              allocates a TTY.
+            --index=index     index of the container if there are multiple
+                              instances of a service [default: 1]
+        """
+        index = int(options.get('--index'))
+        service = project.get_service(options['SERVICE'])
+        try:
+            container = service.get_container(number=index)
+        except ValueError as e:
+            raise UserError(str(e))
+        command = [options['COMMAND']] + options['ARGS']
+        tty = not options["-T"]
+
+        create_exec_options = {
+            "privileged": options["--privileged"],
+            "user": options["--user"],
+            "tty": tty,
+            "stdin": tty,
+        }
+
+        exec_id = container.create_exec(command, **create_exec_options)
+
+        if options['-d']:
+            container.start_exec(exec_id, tty=tty)
+            return
+
+        signals.set_signal_handler_to_shutdown()
+        try:
+            operation = ExecOperation(
+                    project.client,
+                    exec_id,
+                    interactive=tty,
+            )
+            pty = PseudoTerminal(project.client, operation)
+            pty.start()
+        except signals.ShutdownException:
+            log.info("received shutdown exception: closing")
+        exit_code = project.client.exec_inspect(exec_id).get("ExitCode")
+        sys.exit(exit_code)
+
     def help(self, project, options):
         """
         Get help on a command.

compose/container.py

@@ -216,6 +216,12 @@ class Container(object):
     def remove(self, **options):
         return self.client.remove_container(self.id, **options)
 
+    def create_exec(self, command, **options):
+        return self.client.exec_create(self.id, command, **options)
+
+    def start_exec(self, exec_id, **options):
+        return self.client.exec_start(exec_id, **options)
+
     def rename_to_tmp_name(self):
         """Rename the container to a hopefully unique temporary container name
         by prepending the short id.

docs/reference/exec.md

@@ -0,0 +1,29 @@
+<!--[metadata]>
++++
+title = "exec"
+description = "exec"
+keywords = ["fig, composition, compose, docker, orchestration, cli,  exec"]
+[menu.main]
+identifier="exec.compose"
+parent = "smn_compose_cli"
++++
+<![end-metadata]-->
+
+# exec
+
+```
+Usage: exec [options] SERVICE COMMAND [ARGS...]
+
+Options:
+-d                Detached mode: Run command in the background.
+--privileged      Give extended privileges to the process.
+--user USER       Run the command as this user.
+-T                Disable pseudo-tty allocation. By default `docker-compose exec`
+                  allocates a TTY.
+--index=index     index of the container if there are multiple
+                  instances of a service [default: 1]
+```
+
+This is equivalent of `docker exec`. With this subcommand you can run arbitrary
+commands in your services. Commands are by default allocating a TTY, so you can
+do e.g. `docker-compose exec web sh` to get an interactive prompt.

tests/acceptance/cli_test.py

@@ -752,6 +752,24 @@ class CLITestCase(DockerClientTestCase):
         self.project.stop(['simple'])
         wait_on_condition(ContainerCountCondition(self.project, 0))
 
+    def test_exec_without_tty(self):
+        self.base_dir = 'tests/fixtures/links-composefile'
+        self.dispatch(['up', '-d', 'console'])
+        self.assertEqual(len(self.project.containers()), 1)
+
+        stdout, stderr = self.dispatch(['exec', '-T', 'console', 'ls', '-1d', '/'])
+        self.assertEquals(stdout, "/\n")
+        self.assertEquals(stderr, "")
+
+    def test_exec_custom_user(self):
+        self.base_dir = 'tests/fixtures/links-composefile'
+        self.dispatch(['up', '-d', 'console'])
+        self.assertEqual(len(self.project.containers()), 1)
+
+        stdout, stderr = self.dispatch(['exec', '-T', '--user=operator', 'console', 'whoami'])
+        self.assertEquals(stdout, "operator\n")
+        self.assertEquals(stderr, "")
+
     def test_run_service_without_links(self):
         self.base_dir = 'tests/fixtures/links-composefile'
         self.dispatch(['run', 'console', '/bin/true'])