ansible: Add support for free strategy.

ansible_mitogen/plugins/strategy/mitogen.py

@@ -51,6 +51,10 @@ except ImportError:
     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
+import ansible_mitogen.strategy
+import ansible.plugins.strategy.linear
+
+
+class StrategyModule(ansible_mitogen.strategy.StrategyMixin,
+                     ansible.plugins.strategy.linear.StrategyModule):
+    pass

ansible_mitogen/plugins/strategy/mitogen_free.py

@@ -0,0 +1,60 @@
+# 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
+
+import ansible_mitogen.strategy
+import ansible.plugins.strategy.free
+
+
+class StrategyModule(ansible_mitogen.strategy.StrategyMixin,
+                     ansible.plugins.strategy.free.StrategyModule):
+    pass

ansible_mitogen/plugins/strategy/mitogen_linear.py

@@ -0,0 +1,60 @@
+# 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
+
+import ansible_mitogen.strategy
+import ansible.plugins.strategy.linear
+
+
+class StrategyModule(ansible_mitogen.strategy.StrategyMixin,
+                     ansible.plugins.strategy.linear.StrategyModule):
+    pass

ansible_mitogen/strategy.py

@@ -30,7 +30,6 @@ from __future__ import absolute_import
 import os
 
 import ansible.errors
-import ansible.plugins.strategy.linear
 import ansible_mitogen.mixins
 import ansible_mitogen.process
 
@@ -83,12 +82,12 @@ def wrap_connection_loader__get(name, play_context, new_stdin, **kwargs):
     return connection_loader__get(name, play_context, new_stdin, **kwargs)
 
 
-class StrategyModule(ansible.plugins.strategy.linear.StrategyModule):
+class StrategyMixin(object):
     """
-    This strategy enhances the default "linear" strategy by arranging for
-    various Mitogen services to be initialized in the Ansible top-level
-    process, and for worker processes to grow support for using those top-level
-    services to communicate with and execute modules on remote hosts.
+    This mix-in enhances any built-in strategy by arranging for various Mitogen
+    services to be initialized in the Ansible top-level process, and for worker
+    processes to grow support for using those top-level services to communicate
+    with and execute modules on remote hosts.
 
     Mitogen:
 
@@ -182,6 +181,6 @@ class StrategyModule(ansible.plugins.strategy.linear.StrategyModule):
         self._add_connection_plugin_path()
         self._install_wrappers()
         try:
-            return super(StrategyModule, self).run(iterator, play_context)
+            return super(StrategyMixin, self).run(iterator, play_context)
         finally:
             self._remove_wrappers()

docs/ansible.rst

@@ -97,10 +97,12 @@ Installation
 
         [defaults]
         strategy_plugins = /path/to/mitogen-master/ansible_mitogen/plugins/strategy
-        strategy = mitogen
+        strategy = mitogen_linear
 
    The ``strategy`` key is optional. If omitted, you can set the
-   ``ANSIBLE_STRATEGY=mitogen`` environment variable on a per-run basis.
+   ``ANSIBLE_STRATEGY=mitogen_linear`` environment variable on a per-run basis.
+   Like ``mitogen_linear``, the ``mitogen_free`` strategy also exists to mimic
+   the built-in ``free`` strategy.
 
 4. Cross your fingers and try it.
 
@@ -146,8 +148,6 @@ Low Risk
 * Only the ``sudo`` become method is available, however adding new methods is
   straightforward, and eventually at least ``su`` will be included.
 
-* The only supported strategy is ``linear``, which is Ansible's default.
-
 * In some cases ``remote_tmp`` may not be respected.
 
 * The extension's performance benefits do not scale perfectly linearly with the

examples/playbook/ansible.cfg

@@ -1,7 +1,7 @@
 [defaults]
 inventory = hosts
 strategy_plugins = ../../ansible_mitogen/plugins/strategy
-strategy = mitogen
+strategy = mitogen_linear
 library = modules
 retry_files_enabled = False
 forks = 50