Apache Beam支持动态创建disposition的数据流处理,可以在运行时根据计算图中的状态动态确定数据的处理方式。以下是一个示例代码:
import apache_beam as beam
class MyDynamicFn(beam.DoFn):
def process(self, element):
status = get_status(element)
if status == 'success':
yield beam.utils.windowed_value.WindowedValue(element, beam.core.TimestampedValue(1))
elif status == 'failure':
yield beam.utils.windowed_value.WindowedValue(element, beam.core.TimestampedValue(1, 0))
elif status == 'unknown':
yield beam.utils.windowed_value.WindowedValue(element, beam.core.TimestampedValue(0, 0))
data = ['1', '2', '3', '4']
with beam.Pipeline() as p:
result = (
p
| beam.Create(data)
| beam.ParDo(MyDynamicFn())
)
# 定义输出的处理方式
success_output = result[beam.io.WriteFilesResult.OK]
failure_output = result[beam.io.WriteFilesResult.ERROR]
unknown_output = result[None]
# 输出结果
success_output | 'write_success' >> beam.io.WriteToText('success.txt')
failure_output | 'write_failure' >> beam.io.WriteToText('failure.txt')
unknown_output | 'write_unknown' >> beam.io.WriteToText('unknown.txt')
在上述代码中,MyDynamicFn类中的process方法根据元素的状态来动态确定数据的处理方式。处理结果根据不同的状态输出到不同的文件中。
在pipeline中,通过定义不同的输出方式来输出不同的数据。