ansible: restructure package to avoid yet more madness

Ansible's PluginLoader makes up bullshit when it imports a module
(mostly because it has to make up something), therefore we ended up with
duplicate copies of ansible_mitogen loaded: one under
ansible.plugins.*.mitogen, and one under the canonical namespace.

Which broke isinstance().

ansible_mitogen/connection.py

@@ -39,7 +39,7 @@ import mitogen.unix
 from mitogen.utils import cast
 
 import ansible_mitogen.helpers
-from ansible_mitogen.strategy.mitogen import ContextService
+from ansible_mitogen.services import ContextService
 
 
 LOG = logging.getLogger(__name__)

ansible_mitogen/plugins/connection/mitogen.py

@@ -0,0 +1,56 @@
+# Copyright 2017, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+import os.path
+import sys
+
+#
+# This is not the real Connection implementation module, it simply exists as a
+# proxy to the real module, which is loaded using Python's regular import
+# mechanism, to prevent Ansible's PluginLoader from making up a fake name that
+# results in ansible_mitogen plugin modules being loaded twice: once by
+# PluginLoader with a name like "ansible.plugins.connection.mitogen", which is
+# stuffed into sys.modules even though attempting to import it will trigger an
+# ImportError, and once under its canonical name, "ansible_mitogen.connection".
+#
+# Therefore we have a proxy module that imports it under the real name, and
+# sets up the duff PluginLoader-imported module to just contain objects from
+# the real module, so duplicate types don't exist in memory, and things like
+# debuggers and isinstance() work predictably.
+#
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../..')))
+    del base_dir
+
+from ansible_mitogen.connection import Connection
+del os
+del sys

ansible_mitogen/plugins/strategy/mitogen.py

@@ -0,0 +1,56 @@
+# Copyright 2017, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+import os.path
+import sys
+
+#
+# This is not the real Strategy implementation module, it simply exists as a
+# proxy to the real module, which is loaded using Python's regular import
+# mechanism, to prevent Ansible's PluginLoader from making up a fake name that
+# results in ansible_mitogen plugin modules being loaded twice: once by
+# PluginLoader with a name like "ansible.plugins.strategy.mitogen", which is
+# stuffed into sys.modules even though attempting to import it will trigger an
+# ImportError, and once under its canonical name, "ansible_mitogen.strategy".
+#
+# Therefore we have a proxy module that imports it under the real name, and
+# sets up the duff PluginLoader-imported module to just contain objects from
+# the real module, so duplicate types don't exist in memory, and things like
+# debuggers and isinstance() work predictably.
+#
+
+try:
+    import ansible_mitogen
+except ImportError:
+    base_dir = os.path.dirname(__file__)
+    sys.path.insert(0, os.path.abspath(os.path.join(base_dir, '../..')))
+    del base_dir
+
+from ansible_mitogen.strategy import StrategyModule
+del os
+del sys

ansible_mitogen/services.py

@@ -0,0 +1,72 @@
+# Copyright 2017, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+from __future__ import absolute_import
+import mitogen.service
+
+
+class ContextService(mitogen.service.Service):
+    """
+    Used by worker processes connecting back into the top-level process to
+    fetch the single Context instance corresponding to the supplied connection
+    configuration, creating a matching connection if it does not exist.
+
+    For connection methods and their parameters, refer to:
+        http://mitogen.readthedocs.io/en/latest/api.html#context-factories
+
+    This concentrates all SSH connections in the top-level process, which may
+    become a bottleneck. There are multiple ways to fix that: 
+        * creating one .local() child context per CPU and sharding connections
+          between them, using the master process to route messages, or
+        * as above, but having each child create a unique UNIX listener and
+          having workers connect in directly.
+
+    :param dict dct:
+        Parameters passed to mitogen.master.Router.[method](). One key,
+        "method", is popped from the dictionary and used to look up the method.
+
+    :returns mitogen.master.Context:
+        Corresponding Context instance.
+    """
+    handle = 500
+    max_message_size = 1000
+
+    def __init__(self, router):
+        super(ContextService, self).__init__(router)
+        self._context_by_key = {}
+
+    def validate_args(self, args):
+        return isinstance(args, dict)
+
+    def dispatch(self, dct, msg):
+        key = repr(sorted(dct.items()))
+        if key not in self._context_by_key:
+            method = getattr(self.router, dct.pop('method'))
+            self._context_by_key[key] = method(**dct)
+        return self._context_by_key[key]
+

ansible_mitogen/strategy.py

@@ -39,6 +39,7 @@ import mitogen.utils
 import ansible.errors
 import ansible.plugins.strategy.linear
 import ansible_mitogen.mixins
+import ansible_mitogen.services
 
 try:
     from ansible.plugins.loader import action_loader
@@ -90,47 +91,6 @@ def wrap_connection_loader__get(name, play_context, new_stdin):
     return connection_loader__get(name, play_context, new_stdin, **kwargs)
 
 
-class ContextService(mitogen.service.Service):
-    """
-    Used by worker processes connecting back into the top-level process to
-    fetch the single Context instance corresponding to the supplied connection
-    configuration, creating a matching connection if it does not exist.
-
-    For connection methods and their parameters, refer to:
-        http://mitogen.readthedocs.io/en/latest/api.html#context-factories
-
-    This concentrates all SSH connections in the top-level process, which may
-    become a bottleneck. There are multiple ways to fix that: 
-        * creating one .local() child context per CPU and sharding connections
-          between them, using the master process to route messages, or
-        * as above, but having each child create a unique UNIX listener and
-          having workers connect in directly.
-
-    :param dict dct:
-        Parameters passed to mitogen.master.Router.[method](). One key,
-        "method", is popped from the dictionary and used to look up the method.
-
-    :returns mitogen.master.Context:
-        Corresponding Context instance.
-    """
-    handle = 500
-    max_message_size = 1000
-
-    def __init__(self, router):
-        super(ContextService, self).__init__(router)
-        self._context_by_key = {}
-
-    def validate_args(self, args):
-        return isinstance(args, dict)
-
-    def dispatch(self, dct, msg):
-        key = repr(sorted(dct.items()))
-        if key not in self._context_by_key:
-            method = getattr(self.router, dct.pop('method'))
-            self._context_by_key[key] = method(**dct)
-        return self._context_by_key[key]
-
-
 class StrategyModule(ansible.plugins.strategy.linear.StrategyModule):
     """
     This strategy enhances the default "linear" strategy by arranging for
@@ -207,7 +167,7 @@ class StrategyModule(ansible.plugins.strategy.linear.StrategyModule):
         Construct a ContextService and a thread to service requests for it
         arriving from worker processes.
         """
-        self.service = ContextService(self.router)
+        self.service = ansible_mitogen.services.ContextService(self.router)
         self.service_thread = threading.Thread(target=self.service.run)
         self.service_thread.start()
 
@@ -251,9 +211,9 @@ class StrategyModule(ansible.plugins.strategy.linear.StrategyModule):
         Add the mitogen connection plug-in directory to the ModuleLoader path,
         avoiding the need for manual configuration.
         """
-        basedir = os.path.dirname(os.path.dirname(__file__))
+        base_dir = os.path.join(os.path.dirname(__file__), 'plugins')
-        connection_loader.add_directory(os.path.join(basedir, 'connection'))
+        connection_loader.add_directory(os.path.join(base_dir, 'connection'))
-        action_loader.add_directory(os.path.join(basedir, 'actions'))
+        action_loader.add_directory(os.path.join(base_dir, 'actions'))
 
     def run(self, iterator, play_context, result=0):
         self._add_connection_plugin_path()