[Feature] Support impersonate service-account for BigQuery (#900)

* Support impersonate service-account for BigQuery

Signed-off-by: Ching Yi, Chan <[email protected]>

piperider_cli/datasource/bigquery.py

@@ -1,12 +1,13 @@
 import json
 import os
-from typing import List
+from typing import List, Optional
 
 import inquirer
 
 from piperider_cli.error import PipeRiderConnectorError
+
 from . import DataSource
-from .field import PathField, ListField, DataSourceField, _default_validate_func
+from .field import DataSourceField, ListField, _default_validate_func
 
 APPLICATION_DEFAULT_CREDENTIALS = os.path.join(os.path.expanduser('~'), '.config', 'gcloud',
                                                'application_default_credentials.json')
@@ -222,6 +223,14 @@ def engine_args(self):
             args['credentials_path'] = self.credential.get('keyfile')
         elif self.credential.get('method') == AUTH_METHOD_SERVICE_ACCOUNT_JSON:
             args['credentials_info'] = self.credential.get('keyfile_json', {})
+
+        target_service_account_email = self.credential.get('impersonate_service_account', None)
+        if target_service_account_email:
+            # monkey-patch
+            import piperider_cli.datasource.bigquery_patch
+            from sqlalchemy_bigquery import _helpers
+            piperider_cli.datasource.bigquery_patch.target_service_account_email = target_service_account_email
+            _helpers.create_bigquery_client = piperider_cli.datasource.bigquery_patch.create_impersonated_bigquery_client
         return args
 
     def verify_connector(self):

piperider_cli/datasource/bigquery_patch.py

@@ -0,0 +1,79 @@
+import base64
+import json
+from typing import Optional
+
+import google.auth
+import sqlalchemy
+from google.api_core import client_info
+from google.auth import impersonated_credentials
+from google.cloud import bigquery
+from google.oauth2 import service_account
+
+USER_AGENT_TEMPLATE = "sqlalchemy/{}"
+SCOPES = (
+    "https://www.googleapis.com/auth/bigquery",
+    "https://www.googleapis.com/auth/cloud-platform",
+    "https://www.googleapis.com/auth/drive",
+)
+
+target_service_account_email: Optional[str] = None
+
+
+def google_client_info():
+    user_agent = USER_AGENT_TEMPLATE.format(sqlalchemy.__version__)
+    return client_info.ClientInfo(user_agent=user_agent)
+
+
+def create_impersonated_bigquery_client(
+        credentials_info=None,
+        credentials_path=None,
+        credentials_base64=None,
+        default_query_job_config=None,
+        location=None,
+        project_id=None,
+):
+    default_project = None
+
+    if credentials_base64:
+        credentials_info = json.loads(base64.b64decode(credentials_base64))
+
+    if credentials_path:
+        credentials = service_account.Credentials.from_service_account_file(
+            credentials_path
+        )
+        credentials = credentials.with_scopes(SCOPES)
+        default_project = credentials.project_id
+    elif credentials_info:
+        credentials = service_account.Credentials.from_service_account_info(
+            credentials_info
+        )
+        credentials = credentials.with_scopes(SCOPES)
+        default_project = credentials.project_id
+    else:
+        credentials, default_project = google.auth.default(scopes=SCOPES)
+
+    if project_id is None:
+        project_id = default_project
+
+    if target_service_account_email:
+        impersonated_creds = impersonated_credentials.Credentials(
+            source_credentials=credentials,
+            target_principal=target_service_account_email,
+            target_scopes=SCOPES,
+            lifetime=3600  # Duration for which the token is valid (in seconds)
+        )
+        return bigquery.Client(
+            client_info=google_client_info(),
+            project=project_id,
+            credentials=impersonated_creds,
+            location=location,
+            default_query_job_config=default_query_job_config,
+        )
+
+    return bigquery.Client(
+        client_info=google_client_info(),
+        project=project_id,
+        credentials=credentials,
+        location=location,
+        default_query_job_config=default_query_job_config,
+    )