使用Google SDK获取表格时出现TypeError: 'str' object is not callable错误

问题背景 #

我正尝试使用Google SDK获取电子表格，当前登录账号拥有Service Account Token Creator角色，目标服务账号已具备该电子表格的访问权限。

代码示例 #

def build_gcp_sheets_service():
    target_scopes = ['https://www.googleapis.com/auth/spreadsheets.readonly']

    source_credentials, _ = google.auth.default()

    target_credentials = impersonated_credentials.Credentials(
        source_credentials=source_credentials,
        target_principal=config.gcp.local_service_account,
        target_scopes=target_scopes,
        lifetime=60
    )

    service = build('sheets', 'v4', credentials=target_credentials)
    return service


service = build_gcp_sheets_service()

sheet = service.spreadsheets()
request = sheet.values().get(spreadsheetId=file_id, range=sheet_range)
result = request.execute() # Error occurs here

报错信息 #

调用request.execute()时触发以下错误：

Traceback (most recent call last):
  File "/aircraft-detection/ml/gcp.py", line 69, in _fetch_spreadsheet
    result = request.execute()
             ^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/googleapiclient/_helpers.py", line 130, in positional_wrapper
    return wrapped(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/googleapiclient/http.py", line 923, in execute
    resp, content = _retry_request(
                    ^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/googleapiclient/http.py", line 191, in _retry_request
    resp, content = http.request(uri, method, *args, **kwargs)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/google_auth_httplib2.py", line 207, in request
    self.credentials.before_request(self._request, method, uri, request_headers)
  File "/usr/local/lib/python3.11/site-packages/google/auth/credentials.py", line 228, in before_request
    self._blocking_refresh(request)
  File "/usr/local/lib/python3.11/site-packages/google/auth/credentials.py", line 191, in _blocking_refresh
    self.refresh(request)
  File "/usr/local/lib/python3.11/site-packages/google/auth/credentials.py", line 365, in refresh
    self._refresh_token(request)
  File "/usr/local/lib/python3.11/site-packages/google/auth/impersonated_credentials.py", line 289, in _refresh_token
    self._source_credentials._refresh_token(request)
TypeError: 'str' object is not callable

怀疑方向 #

我认为问题出在gcloud配置而非代码，理由：

• 这段代码之前可正常运行，无代码改动情况下突然报错；
• 代码在其他开发者的机器上可正常运行。

已尝试过重装gcloud SDK并重新配置，但问题仍未解决。

排查与解决建议 #

• 检查本地gcloud认证状态
  执行gcloud auth list确认当前活跃账号是否为拥有Service Account Token Creator角色的账号；执行gcloud auth application-default print-access-token验证默认凭证是否有效，若返回错误则重新执行gcloud auth application-default login刷新默认凭证。
• 排查环境变量干扰
  检查是否存在GOOGLE_APPLICATION_CREDENTIALS环境变量，若该变量指向无效的服务账号密钥文件（或路径字符串未被正确解析为凭证对象），会导致google.auth.default()返回异常类型；执行unset GOOGLE_APPLICATION_CREDENTIALS（Linux/macOS）或set GOOGLE_APPLICATION_CREDENTIALS=（Windows）临时清除该变量后重新测试。
• 验证Impersonation权限
  手动测试服务账号模拟是否可行：执行gcloud auth print-access-token --impersonate-service-account=[目标服务账号邮箱]，若报错则需重新确认当前账号的Service Account Token Creator角色是否绑定在目标服务账号的正确层级。
• 对齐依赖版本
  对比其他正常运行机器的google-auth、google-api-python-client版本，执行pip freeze | grep google-查看本地版本，若版本不一致则安装对应版本：

  pip install google-auth==[对应版本] google-api-python-client==[对应版本]
  

内容的提问来源于stack exchange，提问作者Szymon Gołębiowski