Question

我正在尝试执行一个数据流python文件，该文件使用DataFlowPythonOperator通过气流DAG从GCS存储桶读取文本文件。我已经能够独立执行python文件，但是当我通过气流执行它时它失败了。我正在使用服务帐户来验证我的默认gcp连接。我在执行作业时得到的错误是：

{gcp_dataflow_hook.py:108} INFO - Start waiting for DataFlow process to complete.
{models.py:1417} ERROR - DataFlow failed with return code 2
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/airflow/models.py", line 1374, in run
    result = task_copy.execute(context=context)
  File "/usr/local/lib/python2.7/dist-packages/airflow/contrib/operators/dataflow_operator.py", line 182, in execute
    self.py_file, self.py_options)
  File "/usr/local/lib/python2.7/dist-packages/airflow/contrib/hooks/gcp_dataflow_hook.py", line 152, in start_python_dataflow
    task_id, variables, dataflow, name, ["python"] + py_options)
  File "/usr/local/lib/python2.7/dist-packages/airflow/contrib/hooks/gcp_dataflow_hook.py", line 138, in _start_dataflow
    _Dataflow(cmd).wait_for_done()
  File "/usr/local/lib/python2.7/dist-packages/airflow/contrib/hooks/gcp_dataflow_hook.py", line 119, in wait_for_done
    self._proc.returncode))
Exception: DataFlow failed with return code 2

我的气流脚本：

from airflow import DAG
from airflow.contrib.operators.dataflow_operator import DataFlowPythonOperator
from datetime import datetime, timedelta 

# Default DAG parameters
default_args = {
    'owner': 'airflow',
    'depends_on_past': False,
    'email': <email>,
    'email_on_failure': False,
    'email_on_retry': False,
    'start_date': datetime(2018, 4, 30),
    'retries': 1,
    'retry_delay': timedelta(minutes=1),
    'dataflow_default_options': {
        'project': '<Project ID>'        
    }
}

dag = DAG(
    dag_id='df_dag_readfromgcs', 
    default_args=default_args, 
    schedule_interval=timedelta(minutes=60)
    )

task1 = DataFlowPythonOperator(
    task_id='task1',    
    py_file='~<path>/1readfromgcs.py',
    gcp_conn_id='default_google_cloud_connection',
    dag=dag
)

我的Dataflow python文件（1readfromgcs.py）包含以下代码：

from __future__ import absolute_import

import argparse
import logging
import apache_beam as beam
import apache_beam.pipeline as pipeline
import apache_beam.io as beamio
from apache_beam.options.pipeline_options import PipelineOptions
from apache_beam.io import ReadFromText


def runCode(argv=None):
    parser = argparse.ArgumentParser()
    parser.add_argument('--input',
                        default='<Input file path>',
                        help='File name')   
    known_args, pipeline_args = parser.parse_known_args(argv) 

    pipeline_args.extend([
        '--project=<project name>',
        '--runner=DataflowRunner',
        '--job_name=<job name>',
        '--region=europe-west1',
        '--staging_location=<GCS staging location>',
        '--temp_location=<GCS temp location>'
    ])

    pipeline_options = PipelineOptions(pipeline_args)
    p = beam.pipeline.Pipeline(options=pipeline_options)

    rows = p | 'read' >> beam.io.ReadFromText(known_args.input) 

    p.run().wait_until_finish()

if __name__ == '__main__':
    logging.getLogger().setLevel(logging.INFO)
    runCode()

我无法调试并找出此异常的原因，并且根据我在Airflow：https://github.com/apache/incubator-airflow/blob/master/airflow/contrib/hooks/gcp_dataflow_hook.py文件中的调查，错误来自以下几行：

def wait_for_done(self):
        reads = [self._proc.stderr.fileno(), self._proc.stdout.fileno()]
        self.log.info("Start waiting for DataFlow process to complete.")
        while self._proc.poll() is None:
            ret = select.select(reads, [], [], 5)
            if ret is not None:
                for fd in ret[0]:
                    line = self._line(fd)
                    self.log.debug(line[:-1])
            else:
                self.log.info("Waiting for DataFlow process to complete.")
        if self._proc.returncode is not 0:
            raise Exception("DataFlow failed with return code {}".format(
                self._proc.returncode))

感谢您的想法并帮助解决我的问题。

Answer 1

此例外源自_proc subprocess。它从shell返回退出代码。

我还没有使用过这个组件。根据正在执行的内容，此退出代码2将说明退出的原因。例如。 bash中的退出代码表示：

滥用shell builtins

可以连接到

缺少关键字或命令，或权限问题

因此它可能连接到基础DataFlow配置。尝试在模拟用户 airflow 时手动执行文件。

气流异常：数据流失败，返回码为2

1 个答案: