apache-beam

Continuous state in Apache Beam pipeline

為{幸葍}努か 提交于 2019-12-01 06:05:10
问题 I'm developing a beam pipeline for dataflow runner. I need the below functionality in my use case. Read input events from Kafka topic(s). Each Kafka message value derives [userID, Event] pair. For each userID , I need to maintain a profile and based on the current Event , a possible update to the profile is possible. If the profile is updated: Updated profile is written to output stream. The next Event for that userID in the pipeline should refer to the updated profile. I was thinking of

What does object of type '_UnwindowedValues' has no len() mean?

守給你的承諾、 提交于 2019-12-01 04:02:54
I'm using Dataflow 0.5.5 Python. Ran into the following error in very simple code: print(len(row_list)) row_list is a list. Exactly the same code, same data and same pipeline runs perfectly fine on DirectRunner, but throws the following exception on DataflowRunner. What does it mean and how I can solve it? job name: `beamapp-root-0216042234-124125` (f14756f20f567f62): Traceback (most recent call last): File "/usr/local/lib/python2.7/dist-packages/dataflow_worker/batchworker.py", line 544, in do_work work_executor.execute() File "dataflow_worker/executor.py", line 973, in dataflow_worker

Apache Beam: DoFn.Setup equivalent in Python SDK

北战南征 提交于 2019-11-30 21:07:11
What is the recommended way to do expensive one-off initialization in a Beam Python DoFn? The Java SDK has DoFn.Setup , but there doesn't appear to be an equivalent in Beam Python. Is the best way currently to attach objects to threading.local() in the DoFn initializer? Setup and teardown have now been added to the Python SDK and are the recommended way to do expensive one-off initialization in a Beam Python DoFn. Dataflow Python is not particularly transparent about the optimal method for initializing expensive objects. There are a few mechanisms by which objects can be instantiated

Apache Beam: DoFn.Setup equivalent in Python SDK

北战南征 提交于 2019-11-30 17:09:13
问题 What is the recommended way to do expensive one-off initialization in a Beam Python DoFn? The Java SDK has DoFn.Setup, but there doesn't appear to be an equivalent in Beam Python. Is the best way currently to attach objects to threading.local() in the DoFn initializer? 回答1: Setup and teardown have now been added to the Python SDK and are the recommended way to do expensive one-off initialization in a Beam Python DoFn. 回答2: Dataflow Python is not particularly transparent about the optimal

What is the difference between DoFn.Setup and DoFn.StartBundle?

守給你的承諾、 提交于 2019-11-30 15:19:07
What is the difference between these two annotations? DoFn.Setup Annotation for the method to use to prepare an instance for processing bundles of elements. Uses the word "bundle", takes zero arguments. DoFn.StartBundle Annotation for the method to use to prepare an instance for processing a batch of elements. Uses the word "batch", takes zero or one arguments ( StartBundleContext , a way to access PipelineOptions ). What I'm trying to do I need to initialize a library within the DoFn instance, then use that library for every element in the "batch" or "bundle". I wouldn't normally split hairs

Windowing with Apache Beam - Fixed Windows Don't Seem to be Closing?

我们两清 提交于 2019-11-30 09:13:38
We are attempting to use fixed windows on an Apache Beam pipeline (using DirectRunner ). Our flow is as follows: Pull data from pub/sub Deserialize JSON into Java object Window events w/ fixed windows of 5 seconds Using a custom CombineFn , combine each window of Event s into a List<Event> For the sake of testing, simply output the resulting List<Event> Pipeline code: pipeline // Read from pubsub topic to create unbounded PCollection .apply(PubsubIO .<String>read() .topic(options.getTopic()) .withCoder(StringUtf8Coder.of()) ) // Deserialize JSON into Event object .apply("ParseEvent", ParDo .of

What is Apache Beam? [closed]

旧城冷巷雨未停 提交于 2019-11-29 22:05:30
I was going through the Apache posts and found a new term called Beam. Can anybody explain what exactly Apache Beam is? I tried to google out but unable to get a clear answer. Apache Beam is an open source, unified model for defining and executing both batch and streaming data-parallel processing pipelines, as well as a set of language-specific SDKs for constructing pipelines and runtime-specific Runners for executing them. History: The model behind Beam evolved from a number of internal Google data processing projects, including MapReduce , FlumeJava , and Millwheel . This model was

google dataflow read from spanner

亡梦爱人 提交于 2019-11-29 18:44:42
I am trying to read a table from a Google spanner database, and write it to a text file to do a backup, using google dataflow with the python sdk. I have written the following script: from __future__ import absolute_import import argparse import itertools import logging import re import time import datetime as dt import logging import apache_beam as beam from apache_beam.io import iobase from apache_beam.io import WriteToText from apache_beam.io.range_trackers import OffsetRangeTracker, UnsplittableRangeTracker from apache_beam.metrics import Metrics from apache_beam.options.pipeline_options

Does SortValues transform Java SDK extension in Beam only run in hadoop environment?

对着背影说爱祢 提交于 2019-11-29 17:30:22
I have tried the example code of SortValues transform using DirectRunner on local machine (Windows) PCollection<KV<String, KV<String, Integer>>> input = ... PCollection<KV<String, Iterable<KV<String, Integer>>>> grouped = input.apply(GroupByKey.<String, KV<String, Integer>>create()); PCollection<KV<String, Iterable<KV<String, Integer>>>> groupedAndSorted = grouped.apply(SortValues.<String, String, Integer>create(BufferedExternalSorter.options())); but I got the error PipelineExecutionException: java.lang.NoClassDefFoundError: org/apache/hadoop/io/Writable . Does this mean this transform

How to do Async Http Call with Apache Beam (Java)?

ぃ、小莉子 提交于 2019-11-29 17:05:29
Input PCollection is http requests, which is a bounded dataset. I want to make async http call (Java) in a ParDo , parse response and put results into output PCollection. My code is below. Getting exception as following. I cound't figure out the reason. need a guide.... java.util.concurrent.CompletionException: java.lang.IllegalStateException: Can't add element ValueInGlobalWindow{value=streaming.mapserver.backfill.EnrichedPoint@2c59e, pane=PaneInfo.NO_FIRING} to committed bundle in PCollection Call Map Server With Rate Throttle/ParMultiDo(ProcessRequests).output [PCollection] Code : public