79 lines
1.9 KiB
Python
79 lines
1.9 KiB
Python
import abc
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import collections
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import json
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import sys
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from dcos.api import errors, util
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try:
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basestring = basestring
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except NameError:
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# We are in python3 define basestring as str
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basestring = str
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logger = util.get_logger(__name__)
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class Emitter(object):
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"""Abstract class for emitting events."""
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@abc.abstractmethod
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def publish(self, event):
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"""Publishes an event.
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:param event: event to publish
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:type event: any
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"""
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raise NotImplementedError
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class FlatEmitter(Emitter):
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"""Simple emitter that sends all publish events to the provided handler.
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If no handler is provider then use :py:const:`DEFAULT_HANDLER`.
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:param handler: event handler to call when publish is called
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:type handler: func(event) where event is defined in
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:py:func:`FlatEmitter.publish`
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"""
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def __init__(self, handler=None):
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if handler is None:
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self._handler = DEFAULT_HANDLER
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else:
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self._handler = handler
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def publish(self, event):
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"""Publishes an event.
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:param event: event to publish
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:type event: any
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"""
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self._handler(event)
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def print_handler(event):
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"""Default handler for printing event to stdout.
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:param event: event to emit to stdout
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:type event: str, dict or dcos.api.errors.Error
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"""
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if isinstance(event, basestring):
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print(event)
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elif isinstance(event, collections.Mapping) or isinstance(event, list):
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json.dump(event, sys.stdout, sort_keys=True, indent=2)
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print('')
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elif isinstance(event, errors.Error):
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print(event.error())
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else:
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logger.error(
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'Unable to print event. Type not supported: %s, %r.',
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type(event),
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event)
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DEFAULT_HANDLER = print_handler
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"""The default handler for an emitter: :py:func:`print_handler`."""
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