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https://issues.apache.org/jira/browse/BEAM-8335?focusedWorklogId=341568&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-341568
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ASF GitHub Bot logged work on BEAM-8335:
----------------------------------------
Author: ASF GitHub Bot
Created on: 12/Nov/19 00:30
Start Date: 12/Nov/19 00:30
Worklog Time Spent: 10m
Work Description: robertwb commented on pull request #9720: [BEAM-8335]
Add initial modules for interactive streaming support
URL: https://github.com/apache/beam/pull/9720#discussion_r344969049
##########
File path:
sdks/python/apache_beam/runners/interactive/caching/streaming_cache.py
##########
@@ -0,0 +1,124 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# 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
+# the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from __future__ import absolute_import
+
+from apache_beam.portability.api.beam_interactive_api_pb2 import
InteractiveStreamHeader
+from apache_beam.portability.api.beam_interactive_api_pb2 import
InteractiveStreamRecord
+from apache_beam.portability.api.beam_runner_api_pb2 import TestStreamPayload
+from apache_beam.utils import timestamp
+from apache_beam.utils.timestamp import Timestamp
+
+
+class StreamingCache(object):
+ """Abstraction that holds the logic for reading and writing to cache.
+ """
+ def __init__(self, readers):
+ self._readers = readers
+
+ class Reader(object):
+ """Abstraction that reads from PCollection readers.
+
+ This class is an Abstraction layer over multiple PCollection readers to be
+ used for supplying the Interactive Service with TestStream events.
+
+ This class is also responsible for holding the state of the clock,
injecting
+ clock advancement events, and watermark advancement events.
+ """
+ def __init__(self, readers):
+ self._timestamp = Timestamp.of(0)
+ self._readers = {}
+ self._headers = {}
+ readers = [r.read() for r in readers]
+
+ # The header allows for metadata about an entire stream, so that the data
+ # isn't copied per record.
+ for r in readers:
+ header = InteractiveStreamHeader()
+ header.ParseFromString(next(r))
+
+ # Main PCollections in Beam have a tag as None. Deserializing a Proto
+ # with an empty tag becomes an empty string. Here we normalize to what
+ # Beam expects.
+ self._headers[header.tag if header.tag else None] = header
+ self._readers[header.tag if header.tag else None] = r
+
+ self._watermarks = {tag: timestamp.MIN_TIMESTAMP for tag in
self._headers}
+
+ def read(self):
+ """Reads records from PCollection readers.
+ """
+ records = {}
+ for tag, r in self._readers.items():
Review comment:
I'm still having hard time convincing myself that the logic between
_read_next() and read() is correct.
What you're really trying to do is perform a merge sort of the reader on
timestamp. For readability and maintainability, it would probably be best
expressed that way. Whether these are Events that already have the tag embedded
(I'm assuming the backing file format will be compressed, so little to no
overhead) or the input is a dict of {tag: iterator} and the tags applied when
merging depends on which is easier (e.g. when writing).
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Issue Time Tracking
-------------------
Worklog Id: (was: 341568)
> Add streaming support to Interactive Beam
> -----------------------------------------
>
> Key: BEAM-8335
> URL: https://issues.apache.org/jira/browse/BEAM-8335
> Project: Beam
> Issue Type: Improvement
> Components: runner-py-interactive
> Reporter: Sam Rohde
> Assignee: Sam Rohde
> Priority: Major
> Time Spent: 20h 50m
> Remaining Estimate: 0h
>
> This issue tracks the work items to introduce streaming support to the
> Interactive Beam experience. This will allow users to:
> * Write and run a streaming job in IPython
> * Automatically cache records from unbounded sources
> * Add a replay experience that replays all cached records to simulate the
> original pipeline execution
> * Add controls to play/pause/stop/step individual elements from the cached
> records
> * Add ability to inspect/visualize unbounded PCollections
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