Merge pull request #376 from davidszotten/refactor_commands

refactor cli commands to avoid eventlet.monkey_patch

nameko/cli/backdoor.py

@@ -1,15 +1,9 @@
-"""Connect to a nameko backdoor.
-
-If a backdoor is running this will connect to a remote shell.  The
-runner is generally available as `runner`.
-"""
 from __future__ import print_function
 
 import os
 from subprocess import call
 
 from nameko.exceptions import CommandError
-from .actions import FlagAction
 
 
 def main(args):
@@ -44,13 +38,3 @@ def main(args):
         print()
         if choice == 'telnet' and rlwrap:
             call(['reset'])
-
-
-def init_parser(parser):
-    parser.add_argument(
-        'target', metavar='[host:]port', help="(host and) port to connect to")
-    parser.add_argument(
-        '--rlwrap', dest='rlwrap', action=FlagAction,
-        help='Use rlwrap')
-    parser.set_defaults(feature=True)
-    return parser

nameko/cli/commands.py

@@ -0,0 +1,120 @@
+"""Commands are defined in here, with imports inline, to avoid triggering
+imports from other subcommands (e.g. `run` will cause an eventlet monkey-patch
+which we don't want for `shell`)
+
+"""
+from .actions import FlagAction
+
+
+class Command(object):
+    name = None
+
+    @staticmethod
+    def init_parser(parser):
+        raise NotImplementedError  # pragma: no cover
+
+    @staticmethod
+    def main(args):
+        # import inline to avoid triggering imports from other subcommands
+        raise NotImplementedError  # pragma: no cover
+
+
+class Backdoor(Command):
+    """Connect to a nameko backdoor.
+
+    If a backdoor is running this will connect to a remote shell.  The
+    runner is generally available as `runner`.
+    """
+
+    name = 'backdoor'
+
+    @staticmethod
+    def init_parser(parser):
+        parser.add_argument(
+            'target', metavar='[host:]port',
+            help="(host and) port to connect to",
+        )
+        parser.add_argument(
+            '--rlwrap', dest='rlwrap', action=FlagAction,
+            help='Use rlwrap')
+        parser.set_defaults(feature=True)
+        return parser
+
+    @staticmethod
+    def main(args):
+        from .backdoor import main
+        main(args)
+
+
+class Run(Command):
+    """Run nameko services.  Given a python path to a module containing one or
+    more nameko services, will host and run them. By default this will try to
+    find classes that look like services (anything with nameko entrypoints),
+    but a specific service can be specified via
+    ``nameko run module:ServiceClass``.
+    """
+
+    name = 'run'
+
+    @staticmethod
+    def init_parser(parser):
+        parser.add_argument(
+            'services', nargs='+',
+            metavar='module[:service class]',
+            help='python path to one or more service classes to run')
+
+        parser.add_argument(
+            '--config', default='',
+            help='The YAML configuration file')
+
+        parser.add_argument(
+            '--broker', default='amqp://guest:guest@localhost',
+            help='RabbitMQ broker url')
+
+        parser.add_argument(
+            '--backdoor-port', type=int,
+            help='Specify a port number to host a backdoor, which can be'
+            ' connected to for an interactive interpreter within the running'
+            ' service process using `nameko backdoor`.')
+
+        return parser
+
+    @staticmethod
+    def main(args):
+        from .run import main
+        main(args)
+
+
+class Shell(Command):
+    """Launch an interactive python shell for working with remote nameko
+    services.
+
+    This is a regular interactive interpreter, with a special module ``n``
+    added to the built-in namespace, providing ``n.rpc`` and
+    ``n.dispatch_event``.
+    """
+
+    name = 'shell'
+
+    SHELLS = ['bpython', 'ipython', 'plain']
+
+    @classmethod
+    def init_parser(cls, parser):
+        parser.add_argument(
+            '--broker', default='amqp://guest:guest@localhost',
+            help='RabbitMQ broker url')
+        parser.add_argument(
+            '--interface', choices=cls.SHELLS,
+            help='Specify an interactive interpreter interface.')
+        parser.add_argument(
+            '--config', default='',
+            help='The YAML configuration file')
+        return parser
+
+    @staticmethod
+    def main(args):
+        from .shell import main
+        main(args)
+
+
+commands = Command.__subclasses__()  # pylint: disable=E1101

nameko/cli/main.py

@@ -6,7 +6,7 @@
 import yaml
 
 from nameko.exceptions import CommandError, ConfigurationError
-from . import backdoor, run, shell
+from . import commands
 
 ENV_VAR_MATCHER = re.compile(
     r"""
@@ -31,12 +31,11 @@ def setup_parser():
     parser = argparse.ArgumentParser()
     subparsers = parser.add_subparsers()
 
-    for module in [backdoor, run, shell]:
-        name = module.__name__.split('.')[-1]
-        module_parser = subparsers.add_parser(
-            name, description=module.__doc__)
-        module.init_parser(module_parser)
-        module_parser.set_defaults(main=module.main)
+    for command in commands.commands:
+        command_parser = subparsers.add_parser(
+            command.name, description=command.__doc__)
+        command.init_parser(command_parser)
+        command_parser.set_defaults(main=command.main)
     return parser
 
 

nameko/cli/run.py

@@ -1,8 +1,3 @@
-"""Run nameko services.  Given a python path to a module containing one or more
-nameko services, will host and run them. By default this will try to find
-classes that look like services (anything with nameko entrypoints), but a
-specific service can be specified via ``nameko run module:ServiceClass``.  """
-
 from __future__ import print_function
 
 import eventlet
@@ -183,26 +178,3 @@ def main(args):
         )
 
     run(services, config, backdoor_port=args.backdoor_port)
-
-
-def init_parser(parser):
-    parser.add_argument(
-        'services', nargs='+',
-        metavar='module[:service class]',
-        help='python path to one or more service classes to run')
-
-    parser.add_argument(
-        '--config', default='',
-        help='The YAML configuration file')
-
-    parser.add_argument(
-        '--broker', default='amqp://guest:guest@localhost',
-        help='RabbitMQ broker url')
-
-    parser.add_argument(
-        '--backdoor-port', type=int,
-        help='Specify a port number to host a backdoor, which can be connected'
-        ' to for an interactive interpreter within the running service'
-        ' process using `nameko backdoor`.')
-
-    return parser

nameko/cli/shell.py

@@ -1,8 +1,3 @@
-"""Launch an interactive python shell for working with remote nameko services.
-
-This is a regular interactive interpreter, with a special module ``n`` added
-to the built-in namespace, providing ``n.rpc`` and ``n.dispatch_event``.
-"""
 import code
 import os
 import sys
@@ -13,8 +8,7 @@
 from nameko.standalone.rpc import ClusterRpcProxy
 from nameko.standalone.events import event_dispatcher
 
-
-SHELLS = ['bpython', 'ipython', 'plain']
+from .commands import Shell
 
 
 class ShellRunner(object):
@@ -35,7 +29,7 @@ def plain(self):
         code.interact(banner=self.banner, local=self.local)
 
     def start_shell(self, name):
-        available_shells = [name] if name else SHELLS
+        available_shells = [name] if name else Shell.SHELLS
 
         # Support the regular Python interpreter startup script if someone
         # is using it.
@@ -53,19 +47,6 @@ def start_shell(self, name):
         self.plain()
 
 
-def init_parser(parser):
-    parser.add_argument(
-        '--broker', default='amqp://guest:guest@localhost',
-        help='RabbitMQ broker url')
-    parser.add_argument(
-        '--interface', choices=SHELLS,
-        help='Specify an interactive interpreter interface.')
-    parser.add_argument(
-        '--config', default='',
-        help='The YAML configuration file')
-    return parser
-
-
 def make_nameko_helper(config):
     """Create a fake module that provides some convenient access to nameko
     standalone functionality for interactive shell usage.

setup.py

@@ -23,7 +23,7 @@
     packages=find_packages(exclude=['test', 'test.*']),
     install_requires=[
         "eventlet>=0.16.1",
-        "kombu>=3.0.1",
+        "kombu>=3.0.1,<4",
         "mock>=1.2",
         "path.py>=6.2",
         "pyyaml>=3.10",

test/cli/test_backdoor.py

@@ -2,7 +2,7 @@
 from mock import patch, DEFAULT
 import pytest
 
-from nameko.cli.backdoor import main
+from nameko.cli.commands import Backdoor
 from nameko.cli.main import setup_parser
 from nameko.cli.run import setup_backdoor
 from nameko.exceptions import CommandError
@@ -23,7 +23,7 @@ def test_no_telnet():
     with patch('nameko.cli.backdoor.os') as mock_os:
         mock_os.system.return_value = -1
         with pytest.raises(CommandError) as exc:
-            main(args)
+            Backdoor.main(args)
     assert 'Could not find an installed telnet' in str(exc)
 
 
@@ -36,7 +36,7 @@ def test_no_running_backdoor():
         mocks['os'].system.return_value = 0
         mocks['call'].return_value = -1
         with pytest.raises(CommandError) as exc:
-            main(args)
+            Backdoor.main(args)
     assert 'Backdoor unreachable' in str(exc)
 
 
@@ -50,7 +50,7 @@ def test_basic(running_backdoor):
         mock_call = mocks['call']
         mocks['os'].system.return_value = 0
         mock_call.return_value = 0
-        main(args)
+        Backdoor.main(args)
     (cmd, ), _ = mock_call.call_args
     expected = (
         ['rlwrap', 'netcat'] +
@@ -70,7 +70,7 @@ def test_default_host(running_backdoor):
         mock_call = mocks['call']
         mocks['os'].system.return_value = 0
         mock_call.return_value = 0
-        main(args)
+        Backdoor.main(args)
     (cmd, ), _ = mock_call.call_args
     expected = ['rlwrap', 'netcat', 'localhost'] + [str(port)] + ['--close']
     assert cmd == expected
@@ -86,4 +86,4 @@ def test_stop(running_backdoor):
         # choose telnet (skip nc and netcat) and find rlwrap
         mocks['os'].system.side_effect = [-1, -1, 0, 0]
         mocks['call'].side_effect = [KeyboardInterrupt, 0]
-        main(args)
+        Backdoor.main(args)

test/cli/test_main.py

@@ -26,7 +26,7 @@ def fake_argv():
 
 
 def test_run():
-    with patch('nameko.cli.main.run.main') as run:
+    with patch('nameko.cli.run.main') as run:
         main()
     assert run.call_count == 1
     (args,), _ = run.call_args
@@ -35,7 +35,7 @@ def test_run():
 
 @pytest.mark.parametrize('exception', (CommandError, ConfigurationError))
 def test_error(exception, capsys):
-    with patch('nameko.cli.main.run.main') as run:
+    with patch('nameko.cli.run.main') as run:
         run.side_effect = exception('boom')
         main()
     out, _ = capsys.readouterr()