是否可以将Pub/Sub和BigQuery作为Google数据流中的输入？

Question

在我的项目中，我希望在Google Dataflow中使用流式管道来处理发布/订阅消息。在清理输入数据时，我还希望从BigQuery获得一个侧面输入。这会导致两个输入中的一个不工作。

我在流媒体的Pipeline选项中设置了=True，这允许Pub/Sub输入正确处理。但是BigQuery与流媒体管道不兼容（见下面的链接）：

https://cloud.google.com/dataflow/docs/resources/faq#what_are_the_current_limitations_of_streaming_mode

我收到了这个错误：“ValueError： Cloud Pub/Sub目前仅可用于流媒体管道。”基于限制，这是可以理解的。

但我只希望使用BigQuery作为辅助输入，以便将数据映射到传入的发布/订阅数据流。它在本地运行良好，但一旦我尝试在数据流上运行它，它就会返回错误。

有没有人找到一个很好的解决方法？

编辑：在下面添加我的管道框架以供参考：

# Set all options needed to properly run the pipeline
options = PipelineOptions(streaming=True,
                          runner='DataflowRunner', 
                          project=project_id)

p = beam.Pipeline(options = options)

n_tbl_src = (p
         | 'Nickname Table Read' >> beam.io.Read(beam.io.BigQuerySource(
            table = nickname_spec
        )))

# This is the main Dataflow pipeline. This will clean the incoming dataset for importing into BQ.
clean_vote = (p
              | beam.io.gcp.pubsub.ReadFromPubSub(topic = None,
                                     subscription = 'projects/{0}/subscriptions/{1}'
                                                  .format(project_id, subscription_name),
                                     with_attributes = True)
              | 'Isolate Attributes' >> beam.ParDo(IsolateAttrFn())
              | 'Fix Value Types' >> beam.ParDo(FixTypesFn())
              | 'Scrub First Name' >> beam.ParDo(ScrubFnameFn())
              | 'Fix Nicknames' >> beam.ParDo(FixNicknameFn(), n_tbl=AsList(n_tbl_src))
              | 'Scrub Last Name' >> beam.ParDo(ScrubLnameFn()))


# The final dictionary will then be written to BigQuery for storage
(clean_vote | 'Write to BQ' >> beam.io.WriteToBigQuery(
    table = bq_spec,
    write_disposition = beam.io.BigQueryDisposition.WRITE_APPEND,
    create_disposition = beam.io.BigQueryDisposition.CREATE_NEVER
))

# Run the pipeline
p.run()

Answer 1

@Pablo上面的评论是正确的答案。对于任何经历过同样情况的人来说，下面是我脚本中有效的更改。

# This opens the Beam pipeline to run Dataflow
p = beam.Pipeline(options = options)
logging.info('Created Dataflow pipeline.')

# This will pull in all of the recorded nicknames to compare to the incoming PubSubMessages.

client = bigquery.Client()
query_job = client.query("""
    select * from `{0}.{1}.{2}`""".format(project_id, dataset_id, nickname_table_id))
nickname_tbl = query_job.result()
nickname_tbl = [dict(row.items()) for row in nickname_tbl]

# This is the main Dataflow pipeline. This will clean the incoming dataset for importing into BQ.
clean_vote = (p
              | beam.io.gcp.pubsub.ReadFromPubSub(topic = None,
                                     subscription = 'projects/{0}/subscriptions/{1}'
                                                  .format(project_id, subscription_name),
                                     with_attributes = True)
              | 'Isolate Attributes' >> beam.ParDo(IsolateAttrFn())
              | 'Fix Value Types' >> beam.ParDo(FixTypesFn())
              | 'Scrub First Name' >> beam.ParDo(ScrubFnameFn())
              | 'Fix Nicknames' >> beam.ParDo(FixNicknameFn(), n_tbl=nickname_tbl)
              | 'Scrub Last Name' >> beam.ParDo(ScrubLnameFn()))


# The final dictionary will then be written to BigQuery for storage
(clean_vote | 'Write to BQ' >> beam.io.WriteToBigQuery(
    table = bq_spec,
    write_disposition = beam.io.BigQueryDisposition.WRITE_APPEND,
    create_disposition = beam.io.BigQueryDisposition.CREATE_NEVER
))

# Run the pipeline
p.run()