python - python中该公式的具体正则表达式

Question

我正在尝试创建一个正则表达式来匹配我的 s3 存储桶中的此文件。这是我尝试创建的 S3 key ，但现在显然无法正确找到它。下面我提供了我尝试使用此正则表达式方程访问的路径/文件夹的存储桶的快照。

这又是针对 s3 key 的，下面我还将发布我正在使用的代码部分。我引用的是 try 语句内部。

class process_raw_snowplow_event_data(luigi.Task):
    dataset_date = luigi.DateParameter(default=date.today() - timedelta(days=1))
    # force_run = luigi.BoolParameter()
    _start = luigi.DateSecondParameter(default=datetime.utcnow())
    file_root = luigi.Parameter()


def download_s3_file(self, s3_filename):

    local_filename = "/Users/xxx/etl/%s" % s3_filename

    s3_file_full_path =re.compile("snowplow-enrich-output/enriched/archive/run=" + self.dataset_date.strftime("%Y-%m-%d") +r"-\d{2}-\d{2}-\d{2}/*.")


    try:
        s3.download_file(Bucket=os.environ.get('SP_BUCKET'), Key=s3_file_full_path, Filename=local_filename)
    except Exception as e:
        logger.error("%s - Could not retrieve %s because: %s" % ("download_s3_file()", s3_filename, e))
        raise

错误:

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/luigi/worker.py", line 199, in run
new_deps = self._run_get_new_deps()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/luigi/worker.py", line 139, in _run_get_new_deps
task_gen = self.task.run()
  File "target.py", line 123, in run
infile_name = self.download_s3_file(s3_filename)
  File "target.py", line 47, in download_s3_file
s3.download_file(Bucket=os.environ.get('SP_BUCKET'), Key=s3_filename, Filename=local_filename)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/boto3/s3/inject.py", line 172, in download_file
extra_args=ExtraArgs, callback=Callback)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/boto3/s3/transfer.py", line 307, in download_file
future.result()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/s3transfer/futures.py", line 73, in result
return self._coordinator.result()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/s3transfer/futures.py", line 233, in result
raise self._exception
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/s3transfer/tasks.py", line 255, in _main
self._submit(transfer_future=transfer_future, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/s3transfer/download.py", line 353, in _submit
**transfer_future.meta.call_args.extra_args
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/botocore/client.py", line 314, in _api_call
return self._make_api_call(operation_name, kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/botocore/client.py", line 612, in _make_api_call
raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (404) when calling the HeadObject operation: Not Found

谢谢大家

Answer 1

S3.Client.download_file 不支持作为正则表达式的 Key 参数。 ¹

s3_file_full_path 计算结果为类似于以下对象的对象

re.compile(r'snowplow-enrich-output/enriched/archive/run=2019-02-24-\d{2}-\d{2}-\d{2}/*.',
re.UNICODE)

您的存储桶快照中没有任何对象是这样命名的。

解决此问题的唯一方法是列出存储桶对象并将其键与上述正则表达式对象进行匹配。 ²

上面的正则表达式类似于列出名称前缀为 'snowplow-enrich-output/enriched/archive/run=2019-02-24-' 的对象

list_object_kwargs = {
    'Bucket': os.environ.get('SP_BUCKET'),
    'Prefix': 'snowplow-enrich-output/enriched/archive/run=2019-02-24-'
}

def object_keys(contents):
    return [content['Key'] for content in contents]

objects = s3.list_objects_v2(**list_object_kwargs)
found_object_keys = object_keys(objects['Contents'])

while objects['IsTruncated']:
    objects = s3.list_objects_v2(
        ContinuationToken=objects['ContinuationToken'],
        **list_object_kwargs
    )
    found_object_keys.extend(object_keys(objects['Contents']))

try:
    for key in found_object_keys:
        s3.download_file(
            Bucket=os.environ.get('SP_BUCKET'), 
            Key=key)
except Exception as e:
    logger.error(
        "Could not retrieve %s because: %s" % (key, e))
    raise