mitogen/ansible_mitogen/planner.py

368 lines
13 KiB
Python

# 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.
"""
Classes to detect each case from [0] and prepare arguments necessary for the
corresponding Runner class within the target, including preloading requisite
files/modules known missing.
[0] "Ansible Module Architecture", developing_program_flow_modules.html
"""
from __future__ import absolute_import
import json
import logging
import os
from ansible.executor import module_common
import ansible.errors
try:
from ansible.plugins.loader import module_loader
except ImportError: # Ansible <2.4
from ansible.plugins import module_loader
import mitogen
import mitogen.service
import ansible_mitogen.target
import ansible_mitogen.services
LOG = logging.getLogger(__name__)
NO_METHOD_MSG = 'Mitogen: no invocation method found for: '
NO_INTERPRETER_MSG = 'module (%s) is missing interpreter line'
def parse_script_interpreter(source):
"""
Extract the script interpreter and its sole argument from the module
source code.
:returns:
Tuple of `(interpreter, arg)`, where `intepreter` is the script
interpreter and `arg` is its sole argument if present, otherwise
:py:data:`None`.
"""
# Linux requires first 2 bytes with no whitespace, pretty sure it's the
# same everywhere. See binfmt_script.c.
if not source.startswith('#!'):
return None, None
# Find terminating newline. Assume last byte of binprm_buf if absent.
nl = source.find('\n', 0, 128)
if nl == -1:
nl = min(128, len(source))
# Split once on the first run of whitespace. If no whitespace exists,
# bits just contains the interpreter filename.
bits = source[2:nl].strip().split(None, 1)
if len(bits) == 1:
return bits[0], None
return bits[0], bits[1]
class Invocation(object):
"""
Collect up a module's execution environment then use it to invoke
target.run_module() or helpers.run_module_async() in the target context.
"""
def __init__(self, action, connection, module_name, module_args,
remote_tmp, task_vars, templar, env, wrap_async):
#: ActionBase instance invoking the module. Required to access some
#: output postprocessing methods that don't belong in ActionBase at
#: all.
self.action = action
#: Ansible connection to use to contact the target. Must be an
#: ansible_mitogen connection.
self.connection = connection
#: Name of the module ('command', 'shell', etc.) to execute.
self.module_name = module_name
#: Final module arguments.
self.module_args = module_args
#: Value of 'remote_tmp' parameter, to allow target to create temporary
#: files in correct location.
self.remote_tmp = remote_tmp
#: Task variables, needed to extract ansible_*_interpreter.
self.task_vars = task_vars
#: Templar, needed to extract ansible_*_interpreter.
self.templar = templar
#: Final module environment.
self.env = env
#: Boolean, if :py:data:`True`, launch the module asynchronously.
self.wrap_async = wrap_async
#: Initially ``None``, but set by :func:`invoke`. The path on the
#: master to the module's implementation file.
self.module_path = None
#: Initially ``None``, but set by :func:`invoke`. The raw source or
#: binary contents of the module.
self.module_source = None
def __repr__(self):
return 'Invocation(module_name=%s)' % (self.module_name,)
class Planner(object):
"""
A Planner receives a module name and the contents of its implementation
file, indicates whether or not it understands how to run the module, and
exports a method to run the module.
"""
def detect(self, invocation):
"""
Return true if the supplied `invocation` matches the module type
implemented by this planner.
"""
raise NotImplementedError()
def get_should_fork(self, invocation):
"""
Asynchronous tasks must always be forked.
"""
return invocation.wrap_async
def plan(self, invocation, **kwargs):
"""
If :meth:`detect` returned :data:`True`, plan for the module's
execution, including granting access to or delivering any files to it
that are known to be absent, and finally return a dict::
{
# Name of the class from runners.py that implements the
# target-side execution of this module type.
"runner_name": "...",
# Remaining keys are passed to the constructor of the class
# named by `runner_name`.
}
"""
kwargs.setdefault('emulate_tty', True)
kwargs.setdefault('service_context', invocation.connection.parent)
kwargs.setdefault('should_fork', self.get_should_fork(invocation))
kwargs.setdefault('wrap_async', invocation.wrap_async)
return kwargs
class BinaryPlanner(Planner):
"""
Binary modules take their arguments and will return data to Ansible in the
same way as want JSON modules.
"""
runner_name = 'BinaryRunner'
def detect(self, invocation):
return module_common._is_binary(invocation.module_source)
def plan(self, invocation, **kwargs):
invocation.connection._connect()
mitogen.service.call(
context=invocation.connection.parent,
handle=ansible_mitogen.services.FileService.handle,
method='register',
kwargs={
'path': invocation.module_path
}
)
return super(BinaryPlanner, self).plan(
invocation=invocation,
runner_name=self.runner_name,
module=invocation.module_name,
path=invocation.module_path,
args=invocation.module_args,
env=invocation.env,
remote_tmp=invocation.remote_tmp,
**kwargs
)
class ScriptPlanner(BinaryPlanner):
"""
Common functionality for script module planners -- handle interpreter
detection and rewrite.
"""
def _rewrite_interpreter(self, invocation, interpreter):
key = u'ansible_%s_interpreter' % os.path.basename(interpreter).strip()
try:
template = invocation.task_vars[key].strip()
return invocation.templar.template(template)
except KeyError:
return interpreter
def plan(self, invocation, **kwargs):
interpreter, arg = parse_script_interpreter(invocation.module_source)
if interpreter is None:
raise ansible.errors.AnsibleError(NO_INTERPRETER_MSG % (
invocation.module_name,
))
return super(ScriptPlanner, self).plan(
invocation=invocation,
interpreter_arg=arg,
interpreter=self._rewrite_interpreter(
interpreter=interpreter,
invocation=invocation
),
**kwargs
)
class ReplacerPlanner(BinaryPlanner):
"""
The Module Replacer framework is the original framework implementing
new-style modules. It is essentially a preprocessor (like the C
Preprocessor for those familiar with that programming language). It does
straight substitutions of specific substring patterns in the module file.
There are two types of substitutions.
* Replacements that only happen in the module file. These are public
replacement strings that modules can utilize to get helpful boilerplate
or access to arguments.
"from ansible.module_utils.MOD_LIB_NAME import *" is replaced with the
contents of the ansible/module_utils/MOD_LIB_NAME.py. These should only
be used with new-style Python modules.
"#<<INCLUDE_ANSIBLE_MODULE_COMMON>>" is equivalent to
"from ansible.module_utils.basic import *" and should also only apply to
new-style Python modules.
"# POWERSHELL_COMMON" substitutes the contents of
"ansible/module_utils/powershell.ps1". It should only be used with
new-style Powershell modules.
"""
runner_name = 'ReplacerRunner'
def detect(self, invocation):
return module_common.REPLACER in invocation.module_source
class JsonArgsPlanner(ScriptPlanner):
"""
Script that has its interpreter directive and the task arguments
substituted into its source as a JSON string.
"""
runner_name = 'JsonArgsRunner'
def detect(self, invocation):
return module_common.REPLACER_JSONARGS in invocation.module_source
class WantJsonPlanner(ScriptPlanner):
"""
If a module has the string WANT_JSON in it anywhere, Ansible treats it as a
non-native module that accepts a filename as its only command line
parameter. The filename is for a temporary file containing a JSON string
containing the module's parameters. The module needs to open the file, read
and parse the parameters, operate on the data, and print its return data as
a JSON encoded dictionary to stdout before exiting.
These types of modules are self-contained entities. As of Ansible 2.1,
Ansible only modifies them to change a shebang line if present.
"""
runner_name = 'WantJsonRunner'
def detect(self, invocation):
return 'WANT_JSON' in invocation.module_source
class NewStylePlanner(ScriptPlanner):
"""
The Ansiballz framework differs from module replacer in that it uses real
Python imports of things in ansible/module_utils instead of merely
preprocessing the module.
"""
runner_name = 'NewStyleRunner'
def get_should_fork(self, invocation):
"""
In addition to asynchronous tasks, new-style modules should be forked
if mitogen_task_isolation=fork.
"""
return (
super(NewStylePlanner, self).get_should_fork(invocation) or
(invocation.task_vars.get('mitogen_task_isolation') == 'fork')
)
def detect(self, invocation):
return 'from ansible.module_utils.' in invocation.module_source
class ReplacerPlanner(NewStylePlanner):
runner_name = 'ReplacerRunner'
def detect(self, invocation):
return module_common.REPLACER in invocation.module_source
class OldStylePlanner(ScriptPlanner):
runner_name = 'OldStyleRunner'
def detect(self, invocation):
# Everything else.
return True
_planners = [
BinaryPlanner,
# ReplacerPlanner,
NewStylePlanner,
JsonArgsPlanner,
WantJsonPlanner,
OldStylePlanner,
]
def get_module_data(name):
path = module_loader.find_plugin(name, '')
with open(path, 'rb') as fp:
source = fp.read()
return path, source
def invoke(invocation):
"""
Find a suitable Planner that knows how to run `invocation`.
"""
(invocation.module_path,
invocation.module_source) = get_module_data(invocation.module_name)
for klass in _planners:
planner = klass()
if planner.detect(invocation):
LOG.debug('%r accepted %r (filename %r)', planner,
invocation.module_name, invocation.module_path)
return invocation.action._postprocess_response(
invocation.connection.call(
ansible_mitogen.target.run_module,
planner.plan(invocation),
)
)
LOG.debug('%r rejected %r', planner, invocation.module_name)
raise ansible.errors.AnsibleError(NO_METHOD_MSG + repr(invocation))