add detach plugin (#320)

* add detach plugin
* Implementing conflict feedback and resolution for default operating mode for detach and no-tty present.

Signed-off-by: Tully Foote <[email protected]>
Co-authored-by: Tully Foote <[email protected]>

setup.py

@@ -46,6 +46,7 @@
         ],
         'rocker.extensions': [
             'cuda = rocker.nvidia_extension:Cuda',
+            'detach = rocker.extensions:Detach',
             'devices = rocker.extensions:Devices',
             'dev_helpers = rocker.extensions:DevHelpers',
             'env = rocker.extensions:Environment',

src/rocker/cli.py

@@ -21,6 +21,10 @@
 from .core import RockerExtensionManager
 from .core import DependencyMissing
 from .core import ExtensionError
+from .core import OPERATIONS_DRY_RUN
+from .core import OPERATIONS_INTERACTIVE
+from .core import OPERATIONS_NON_INTERACTIVE
+from .core import OPERATION_MODES
 
 from .os_detector import detect_os
 
@@ -32,7 +36,7 @@ def main():
         formatter_class=argparse.ArgumentDefaultsHelpFormatter)
     parser.add_argument('image')
     parser.add_argument('command', nargs='*', default='')
-    parser.add_argument('--noexecute', action='store_true', help='Deprecated')
+    parser.add_argument('--noexecute', action='store_true', help='Deprecated') # TODO(tfoote) add when 3.13 is minimum supported, deprecated=True 
     parser.add_argument('--nocache', action='store_true')
     parser.add_argument('--nocleanup', action='store_true', help='do not remove the docker container when stopped')
     parser.add_argument('--persist-image', action='store_true', help='do not remove the docker image when stopped', default=False) #TODO(tfoote) Add a name to it if persisting
@@ -56,6 +60,34 @@ def main():
         args_dict['mode'] = OPERATIONS_DRY_RUN
         print('DEPRECATION Warning: --noexecute is deprecated for --mode dry-run please switch your usage by December 2020')
 
+    # validate_operating_mode
+    operating_mode = args_dict.get('mode')
+    # Don't try to be interactive if there's no tty
+    if not os.isatty(sys.__stdin__.fileno()):
+        if operating_mode == OPERATIONS_INTERACTIVE:
+            parser.error("No tty detected cannot operate in interactive mode")
+        elif not operating_mode:
+            print("No tty detected for stdin defaulting mode to non-interactive")
+            args_dict['mode'] = OPERATIONS_NON_INTERACTIVE
+
+    # Check if detach extension is active and deconflict with interactive
+    detach_active = args_dict.get('detach')
+    operating_mode = args_dict.get('mode')
+    if detach_active:
+        if operating_mode == OPERATIONS_INTERACTIVE:
+            parser.error("Command line option --mode=interactive and --detach are mutually exclusive")
+        elif not operating_mode:
+            print(f"Detach extension active, defaulting mode to {OPERATIONS_NON_INTERACTIVE}")
+            args_dict['mode'] = OPERATIONS_NON_INTERACTIVE
+    # TODO(tfoote) Deal with the case of dry-run + detach
+    # Right now the printed results will include '-it'
+    # But based on testing the --detach overrides -it in docker so it's ok.
+
+    # Default to non-interactive if unset
+    if args_dict.get('mode') not in OPERATION_MODES:
+        print("Mode unset, defaulting to interactive")
+        args_dict['mode'] = OPERATIONS_NON_INTERACTIVE
+
     try:
         active_extensions = extension_manager.get_active_extensions(args_dict)
     except ExtensionError as e:

src/rocker/core.py

@@ -134,8 +134,7 @@ def extend_cli_parser(self, parser, default_args={}):
                 print("Extension %s doesn't support default arguments. Please extend it." % p.get_name())
                 p.register_arguments(parser)
         parser.add_argument('--mode', choices=OPERATION_MODES,
-            default=OPERATIONS_INTERACTIVE,
-            help="Choose mode of operation for rocker")
+            help="Choose mode of operation for rocker, default interactive unless detached.")
         parser.add_argument('--image-name', default=None,
             help='Tag the final image, useful with dry-run')
         parser.add_argument('--extension-blacklist', nargs='*',
@@ -361,9 +360,6 @@ def get_operating_mode(self, args):
         # Default to non-interactive if unset
         if operating_mode not in OPERATION_MODES:
             operating_mode = OPERATIONS_NON_INTERACTIVE
-        if operating_mode == OPERATIONS_INTERACTIVE and not os.isatty(sys.__stdin__.fileno()):
-            operating_mode = OPERATIONS_NON_INTERACTIVE
-            print("No tty detected for stdin forcing non-interactive")
         return operating_mode
 
     def generate_docker_cmd(self, command='', **kwargs):

src/rocker/extensions.py

@@ -32,6 +32,32 @@ def name_to_argument(name):
 
 from .core import RockerExtension
 
+class Detach(RockerExtension):
+    @staticmethod
+    def get_name():
+        return 'detach'
+
+    def __init__(self):
+        self.name = Detach.get_name()
+
+    def get_docker_args(self, cliargs):
+        args = ''
+        detach = cliargs.get('detach', False)
+        if detach:
+            args += ' --detach'
+        return args
+
+    @staticmethod
+    def register_arguments(parser, defaults):
+        parser.add_argument(
+            '-d',
+            '--detach',
+            action='store_true',
+            default=defaults.get('detach', False),
+            help='Run the container in the background.'
+        )
+
+
 class Devices(RockerExtension):
     @staticmethod
     def get_name():

test/test_core.py

@@ -226,11 +226,11 @@ def test_docker_cmd_interactive(self):
 
         # TODO(tfoote) mock this appropriately
         # google actions tests don't have a tty, local tests do
-        import os, sys
-        if os.isatty(sys.__stdin__.fileno()):
-            self.assertIn('-it', dig.generate_docker_cmd(mode='interactive'))
-        else:
-            self.assertNotIn('-it', dig.generate_docker_cmd(mode='interactive'))
+        # import os, sys
+        # if os.isatty(sys.__stdin__.fileno()):
+        #     self.assertIn('-it', dig.generate_docker_cmd(mode='interactive'))
+        # else:
+        self.assertIn('-it', dig.generate_docker_cmd(mode='interactive'))
 
         self.assertNotIn('-it', dig.generate_docker_cmd(mode='non-interactive'))
 

test/test_extension.py

@@ -52,6 +52,40 @@ def test_name_to_argument(self):
         self.assertEqual(name_to_argument('as-df'), '--as-df')
 
 
+class DetachExtensionTest(unittest.TestCase):
+
+    def setUp(self):
+        # Work around interference between empy Interpreter
+        # stdout proxy and test runner. empy installs a proxy on stdout
+        # to be able to capture the information.
+        # And the test runner creates a new stdout object for each test.
+        # This breaks empy as it assumes that the proxy has persistent
+        # between instances of the Interpreter class
+        # empy will error with the exception
+        # "em.Error: interpreter stdout proxy lost"
+        em.Interpreter._wasProxyInstalled = False
+
+    def test_detach_extension(self):
+        plugins = list_plugins()
+        detach_plugin = plugins['detach']
+        self.assertEqual(detach_plugin.get_name(), 'detach')
+
+        p = detach_plugin()
+        self.assertTrue(plugin_load_parser_correctly(detach_plugin))
+
+        mock_cliargs = {'detach': True}
+        args = p.get_docker_args(mock_cliargs)
+        self.assertTrue('--detach' in args)
+
+        mock_cliargs = {'detach': False}
+        args = p.get_docker_args(mock_cliargs)
+        self.assertTrue('--detach' not in args)
+
+        mock_cliargs = {}
+        args = p.get_docker_args(mock_cliargs)
+        self.assertTrue('--detach' not in args)
+
+
 class DevicesExtensionTest(unittest.TestCase):
 
     def setUp(self):