bigquery: modify LoadJob (#4103)

This PR handles loading from GCS. Loading from a local
file will be done separately.

Author: jba

bigquery/google/cloud/bigquery/__init__.py

@@ -35,6 +35,7 @@
 from google.cloud.bigquery.job import CopyJobConfig
 from google.cloud.bigquery.job import ExtractJobConfig
 from google.cloud.bigquery.job import QueryJobConfig
+from google.cloud.bigquery.job import LoadJobConfig
 from google.cloud.bigquery.schema import SchemaField
 from google.cloud.bigquery.table import Table
 
@@ -47,6 +48,7 @@
     'CopyJobConfig',
     'ExtractJobConfig',
     'QueryJobConfig',
+    'LoadJobConfig',
     'ScalarQueryParameter',
     'SchemaField',
     'StructQueryParameter',

bigquery/google/cloud/bigquery/client.py

@@ -19,6 +19,8 @@
 import collections
 import uuid
 
+import six
+
 from google.api.core import page_iterator
 from google.cloud.client import ClientWithProject
 from google.cloud.bigquery._http import Connection
@@ -490,26 +492,37 @@ def list_jobs(self, max_results=None, page_token=None, all_users=None,
             max_results=max_results,
             extra_params=extra_params)
 
-    def load_table_from_storage(self, job_id, destination, *source_uris):
-        """Construct a job for loading data into a table from CloudStorage.
+    def load_table_from_storage(self, source_uris, destination,
+                                job_id=None, job_config=None):
+        """Starts a job for loading data into a table from CloudStorage.
 
         See
         https://cloud.google.com/bigquery/docs/reference/rest/v2/jobs#configuration.load
 
-        :type job_id: str
-        :param job_id: Name of the job.
+        :type source_uris: One of:
+                           str
+                           sequence of string
+        :param source_uris: URIs of data files to be loaded; in format
+                            ``gs://<bucket_name>/<object_name_or_glob>``.
 
-        :type destination: :class:`google.cloud.bigquery.table.Table`
+        :type destination: :class:`google.cloud.bigquery.table.TableReference`
         :param destination: Table into which data is to be loaded.
 
-        :type source_uris: sequence of string
-        :param source_uris: URIs of data files to be loaded; in format
-                            ``gs://<bucket_name>/<object_name_or_glob>``.
+        :type job_id: str
+        :param job_id: Name of the job.
+
+        :type job_config: :class:`google.cloud.bigquery.job.LoadJobConfig`
+        :param job_config: (Optional) Extra configuration options for the job.
 
         :rtype: :class:`google.cloud.bigquery.job.LoadJob`
         :returns: a new ``LoadJob`` instance
         """
-        return LoadJob(job_id, destination, source_uris, client=self)
+        job_id = _make_job_id(job_id)
+        if isinstance(source_uris, six.string_types):
+            source_uris = [source_uris]
+        job = LoadJob(job_id, source_uris, destination, self, job_config)
+        job.begin()
+        return job
 
     def copy_table(self, sources, destination, job_id=None, job_config=None):
         """Start a job for copying one or more tables into another table.