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