Question

因此，我尝试通过云功能更新云Firestore中的日期时间字段，如下所示：

transaction.update(doc_ref, {'dateTimeField1': dateTimeValue})

Google在云函数的事件参数中以字符串%Y-%m-%dT%H:%M:%SZ或%Y-%m-%dT%H:%M:%S.%fZ的形式将日期时间对象作为字符串发送。
例如：2019-01-25T15:25:03.881Z

我将其转换为datetime对象，如下所示：

try:
    datetime_obj = datetime.datetime.strptime(datetime_obj, '%Y-%m-%dT%H:%M:%S.%fZ')
except:
    datetime_obj = datetime.datetime.strptime(datetime_obj, '%Y-%m-%dT%H:%M:%SZ')
datetime_obj = datetime_obj.replace(tzinfo=timezone('UTC'))

但是当我尝试执行该操作时，出现以下错误： AttributeError: _nanosecond

跟踪：
File "/env/local/lib/python3.7/site-packages/google/cloud/firestore_v1beta1/batch.py", line 112, in update reference._document_path, field_updates, option File "/env/local/lib/python3.7/site-packages/google/cloud/firestore_v1beta1/_helpers.py", line 822, in pbs_for_update update_pb = extractor.get_update_pb(document_path) File "/env/local/lib/python3.7/site-packages/google/cloud/firestore_v1beta1/_helpers.py", line 459, in get_update_pb name=document_path, fields=encode_dict(self.set_fields) File "/env/local/lib/python3.7/site-packages/google/cloud/firestore_v1beta1/_helpers.py", line 215, in encode_dict return {key: encode_value(value) for key, value in six.iteritems(values_dict)} File "/env/local/lib/python3.7/site-packages/google/cloud/firestore_v1beta1/_helpers.py", line 215, in <dictcomp> return {key: encode_value(value) for key, value in six.iteritems(values_dict)} File "/env/local/lib/python3.7/site-packages/google/cloud/firestore_v1beta1/_helpers.py", line 169, in encode_value return document_pb2.Value(timestamp_value=value.timestamp_pb()) File "/env/local/lib/python3.7/site-packages/google/api_core/datetime_helpers.py", line 278, in timestamp_pb nanos = self._nanosecond or self.microsecond * 1000 AttributeError: _nanosecond

是否允许通过交易设置日期时间，或者我在这里错过了什么？

编辑：
代码段：

@firestore.transactional
def update_datetime_field(transaction, doc_ref, datetime_value):
    try:
        datetime_obj = datetime.datetime.strptime(datetime_value, '%Y-%m-%dT%H:%M:%S.%fZ')
    except:
        datetime_obj = datetime.datetime.strptime(datetime_value, '%Y-%m-%dT%H:%M:%SZ')
    datetime_obj = datetime_obj.replace(tzinfo=timezone('UTC'))
    # Example of datetime_obj -> datetime.datetime(2019, 1, 25, 15, 25, 3, 881000, tzinfo=<UTC>)
    transaction.update(doc_ref, {'datetimeField1': datetime_obj})
    return True

更多信息：

在更新文档时触发上述代码 collection1/document1/collection2/document2
datetime对象是标准库中python的日期时间
我正在尝试通过使用pytz更改时区来将日期转换为UTC

编辑2：

更好的完整图片：

from firebase_admin import credentials, firestore

# initialize firebase admin sdk
creds = credentials.ApplicationDefault()
firebase_admin.initialize_app(creds,{'projectId': 'myProjectId'})


@firestore.transactional
def update_datetime_field(transaction, doc_ref, datetime_value):
    try:
        datetime_obj = datetime.datetime.strptime(datetime_value, '%Y-%m-%dT%H:%M:%S.%fZ')
    except:
        datetime_obj = datetime.datetime.strptime(datetime_value, '%Y-%m-%dT%H:%M:%SZ')
    datetime_obj = datetime_obj.replace(tzinfo=timezone('UTC'))
    # Example of datetime_obj -> datetime.datetime(2019, 1, 25, 15, 25, 3, 881000, tzinfo=<UTC>)
    transaction.update(doc_ref, {'datetimeField1': datetime_obj})
    return True

def update_datetime_in_transaction(event, context):
    datetime_value = event['value']['fields']['datetimeField1']['timestampValue']
    # this looks something like 2019-01-25T15:25:03.881Z

    # prepare document reference to document
    doc_ref = prepare_doc_ref(event, context)

    # update_datetime_field
    client = firestore.client()
    transaction = client.transaction()
    update_datetime_field(transaction, doc_ref, datetime_value)

    return True

编辑3：

事件参数的屏幕截图：

控制台的屏幕截图：

Answer 1

因此，firestore python sdk希望使用_nanosecond属性，该属性目前在python标准库的日期时间中不可用（将在以后添加。更多详细信息here）

因此，在检查了他们的代码库之后，我发现了一个名为DatetimeWithNanoseconds的类，该类为传统的日期时间对象添加了纳秒级的支持。

该类的代码（google / api_core中的datetime_helpers.py文件）如下（为简洁起见，故意删除了某些部分）：

class DatetimeWithNanoseconds(datetime.datetime):
"""Track nanosecond in addition to normal datetime attrs.

Nanosecond can be passed only as a keyword argument.
"""
__slots__ = ('_nanosecond',)

@classmethod
def from_rfc3339(cls, stamp):
    with_nanos = _RFC3339_NANOS.match(stamp)
    if with_nanos is None:
        raise ValueError(
            'Timestamp: {}, does not match pattern: {}'.format(
                stamp, _RFC3339_NANOS.pattern))
    bare = datetime.datetime.strptime(
        with_nanos.group('no_fraction'), _RFC3339_NO_FRACTION)
    fraction = with_nanos.group('nanos')
    if fraction is None:
        nanos = 0
    else:
        scale = 9 - len(fraction)
        nanos = int(fraction) * (10 ** scale)
    return cls(bare.year, bare.month, bare.day,
               bare.hour, bare.minute, bare.second,
               nanosecond=nanos, tzinfo=pytz.UTC)

因此，现在，我可以使用datetime.datetime方法使用此类而不是DatetimeWithNanoseconds.from_rfc3339(timestamp)来解析在云函数的事件参数中以字符串形式发送的日期时间。

示例：

from google.api_core.datetime_helpers import DatetimeWithNanoseconds

d1 = DatetimeWithNanoseconds.from_rfc3339('2019-01-25T15:25:03.881Z')
print(d1)
# DatetimeWithNanoseconds(2019, 1, 25, 15, 25, 3, 881000, tzinfo=<UTC>)

该类还具有rfc3339()方法来为您提供字符串表示形式。

示例：

d1.rfc3339()
# 2019-01-25T15:25:03.881Z

替代解决方案：

您也可以使用pandas.Timestamp()代替DatetimeWithNanoseconds.from_rfc3339()。

示例：

import pandas as pd

d1 = pd.Timestamp('2019-01-25T15:25:03.881Z')
print(d1)
# Timestamp('2019-01-25 15:25:03.881000+0000', tz='UTC')

我建议使用DatetimeWithNanoseconds，因为它与sdk一起提供，并且您不需要在requirements.txt中添加熊猫的额外依赖关系，这可以增加冷启动期间的调用延迟。更多详细信息here。

希望这会有所帮助。

AttributeError：在交易中更新日期时间时为_nanosecond

1 个答案: