#
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# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
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# http://www.apache.org/licenses/LICENSE-2.0
#
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"""For rendering pipeline graph in HTML-compatible format.
This module is experimental. No backwards-compatibility guarantees.
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import abc
import os
import subprocess
from future.utils import with_metaclass
from apache_beam.utils.plugin import BeamPlugin
[docs]class PipelineGraphRenderer(with_metaclass(abc.ABCMeta, BeamPlugin)):
"""Abstract class for renderers, who decide how pipeline graphs are rendered.
"""
[docs] @classmethod
@abc.abstractmethod
def option(cls):
"""The corresponding rendering option for the renderer.
"""
raise NotImplementedError
[docs] @abc.abstractmethod
def render_pipeline_graph(self, pipeline_graph):
"""Renders the pipeline graph in HTML-compatible format.
Args:
pipeline_graph: (pipeline_graph.PipelineGraph) the graph to be rendererd.
Returns:
unicode, str or bytes that can be expressed as HTML.
"""
raise NotImplementedError
[docs]class MuteRenderer(PipelineGraphRenderer):
"""Use this renderer to mute the pipeline display.
"""
[docs] @classmethod
def option(cls):
return 'mute'
[docs] def render_pipeline_graph(self, pipeline_graph):
return ''
[docs]class TextRenderer(PipelineGraphRenderer):
"""This renderer simply returns the dot representation in text format.
"""
[docs] @classmethod
def option(cls):
return 'text'
[docs] def render_pipeline_graph(self, pipeline_graph):
return pipeline_graph.get_dot()
[docs]class PydotRenderer(PipelineGraphRenderer):
"""This renderer renders the graph using pydot.
It depends on
1. The software Graphviz: https://www.graphviz.org/
2. The python module pydot: https://pypi.org/project/pydot/
"""
[docs] @classmethod
def option(cls):
return 'graph'
[docs] def render_pipeline_graph(self, pipeline_graph):
return pipeline_graph._get_graph().create_svg().decode("utf-8") # pylint: disable=protected-access
[docs]def get_renderer(option=None):
"""Get an instance of PipelineGraphRenderer given rendering option.
Args:
option: (str) the rendering option.
Returns:
(PipelineGraphRenderer)
"""
if option is None:
if os.name == 'nt':
exists = subprocess.call(['where', 'dot.exe']) == 0
else:
exists = subprocess.call(['which', 'dot']) == 0
if exists:
option = 'graph'
else:
option = 'text'
renderer = [r for r in PipelineGraphRenderer.get_all_subclasses()
if option == r.option()]
if len(renderer) == 0:
raise ValueError()
elif len(renderer) == 1:
return renderer[0]()
else:
raise ValueError('Found more than one renderer for option: %s',
option)