我想在ParDo函数中调用beam.io.Write(beam.io.BigQuerySink(..))
操作,为PCollection
中的每个键生成一个单独的BigQuery表(我使用的是python SDK)。这是两个相似的主题,但遗憾的是没有帮助:
1)https://stackoverflow.com/questions/31156774/about-key-grouping-with-groupbykey
2)Dynamic table name when writing to BQ from dataflow pipelines
当我执行以下代码时,第一个键的行被插入到BigQuery中,然后管道失败并出现以下错误。我真的很感激任何有关我做错的建议或任何有关如何解决它的建议。
管道代码:
rows = p | 'read_bq_table' >> beam.io.Read(beam.io.BigQuerySource(query=query))
class par_upload(beam.DoFn):
def process(self, context):
key, value = context.element
### This block causes issues ###
value | 'write_to_bq' >> beam.io.Write(
beam.io.BigQuerySink(
'PROJECT-NAME:analytics.first_table', #will be replace by a dynamic name based on key
schema=schema,
write_disposition=beam.io.BigQueryDisposition.WRITE_APPEND,
create_disposition=beam.io.BigQueryDisposition.CREATE_IF_NEEDED
)
)
### End block ######
return [value]
### Following part works fine ###
filtered = (rows | 'filter_rows' >> beam.Filter(lambda row: row['topic'] == 'analytics')
| 'apply_projection' >> beam.Map(apply_projection, projection_fields)
| 'group_by_key' >> beam.GroupByKey()
| 'par_upload_to_bigquery' >> beam.ParDo(par_upload())
| 'flat_map' >> beam.FlatMap(lambda l: l) #this step is just for testing
)
### This part works fine if I comment out the 'write_to_bq' block above
filtered | 'write_to_bq' >> beam.io.Write(
beam.io.BigQuerySink(
'PROJECT-NAME:analytics.another_table',
schema=schema,
write_disposition=beam.io.BigQueryDisposition.WRITE_TRUNCATE,
create_disposition=beam.io.BigQueryDisposition.CREATE_IF_NEEDED)
)
错误讯息:
INFO:oauth2client.client:Attempting refresh to obtain initial access_token
INFO:oauth2client.client:Attempting refresh to obtain initial access_token
INFO:root:Writing 1 rows to PROJECT-NAME:analytics.first_table table.
INFO:root:Final: Debug counters: {'element_counts': Counter({'CreatePInput0': 1, 'write_to_bq/native_write': 1})}
ERROR:root:Error while visiting par_upload_to_bigquery
Traceback (most recent call last):
File "split_events.py", line 137, in <module>
run()
File "split_events.py", line 132, in run
p.run()
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/pipeline.py", line 159, in run
return self.runner.run(self)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/direct_runner.py", line 102, in run
super(DirectPipelineRunner, self).run(pipeline)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/runner.py", line 98, in run
pipeline.visit(RunVisitor(self))
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/pipeline.py", line 182, in visit
self._root_transform().visit(visitor, self, visited)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/pipeline.py", line 419, in visit
part.visit(visitor, pipeline, visited)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/pipeline.py", line 422, in visit
visitor.visit_transform(self)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/runner.py", line 93, in visit_transform
self.runner.run_transform(transform_node)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/runner.py", line 168, in run_transform
return m(transform_node)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/direct_runner.py", line 98, in func_wrapper
func(self, pvalue, *args, **kwargs)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/direct_runner.py", line 180, in run_ParDo
runner.process(v)
File "apache_beam/runners/common.py", line 133, in apache_beam.runners.common.DoFnRunner.process (apache_beam/runners/common.c:4483)
File "apache_beam/runners/common.py", line 139, in apache_beam.runners.common.DoFnRunner.process (apache_beam/runners/common.c:4311)
File "apache_beam/runners/common.py", line 150, in apache_beam.runners.common.DoFnRunner.reraise_augmented (apache_beam/runners/common.c:4677)
File "apache_beam/runners/common.py", line 137, in apache_beam.runners.common.DoFnRunner.process (apache_beam/runners/common.c:4245)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/typehints/typecheck.py", line 149, in process
return self.run(self.dofn.process, context, args, kwargs)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/typehints/typecheck.py", line 134, in run
result = method(context, *args, **kwargs)
File "split_events.py", line 73, in process
create_disposition=beam.io.BigQueryDisposition.CREATE_IF_NEEDED
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/transforms/ptransform.py", line 724, in __ror__
return self.transform.__ror__(pvalueish, self.label)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/transforms/ptransform.py", line 445, in __ror__
return _MaterializePValues(cache).visit(result)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/transforms/ptransform.py", line 105, in visit
return self._pvalue_cache.get_unwindowed_pvalue(node)
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/runner.py", line 262, in get_unwindowed_pvalue
return [v.value for v in self.get_pvalue(pvalue)]
File "/Users/dimitri/anaconda/lib/python2.7/site-packages/apache_beam/runners/runner.py", line 244, in get_pvalue
value_with_refcount = self._cache[self.key(pvalue)]
KeyError: "(4384177040, None) [while running 'par_upload_to_bigquery']"
编辑(在第一个回答之后):
我没有意识到我的值需要是PCollection
。
我现在已将代码更改为此(这可能非常低效):
key_pipe = p | 'pipe_' + key >> beam.Create(value)
key_pipe | 'write_' + key >> beam.io.Write(beam.io.BigQuerySink(..))
现在可以正常使用本地但不能使用BlockingDataflowPipelineRunner
: - (
管道因以下错误而失败:
JOB_MESSAGE_ERROR: (979394c29490e588): Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/dataflow_worker/batchworker.py", line 474, in do_work
work_executor.execute()
File "dataflow_worker/executor.py", line 901, in dataflow_worker.executor.MapTaskExecutor.execute (dataflow_worker/executor.c:24331)
op.start()
File "dataflow_worker/executor.py", line 465, in dataflow_worker.executor.DoOperation.start (dataflow_worker/executor.c:14193)
def start(self):
File "dataflow_worker/executor.py", line 469, in dataflow_worker.executor.DoOperation.start (dataflow_worker/executor.c:13499)
fn, args, kwargs, tags_and_types, window_fn = (
ValueError: too many values to unpack (expected 5)
答案 0 :(得分:0)
在类似的主题中,在ParDo中进行BigQuery编写操作的唯一建议是直接使用BigQuery API,或者使用client。
您编写的代码是将Dataflow ParDo class beam.io.BigQuerySink()
放入DoFn函数中。 ParDo类希望在工作代码示例中使用PCollection
之类的filtered
。对于在value
上工作的无效代码,情况并非如此。
我认为最简单的选择是查看gcloud-python BigQuery函数insert_data()
并将其放入ParDo中。