Fix requirements, handle missing requirements

Author: alonme

dev_requirements.txt

@@ -1,7 +1,7 @@
 sqlalchemy>=1.1.9
-google-cloud-bigquery[bqstorage]>=1.25.0
-google-cloud-bigquery-storage[fastavro]>=1.0.0
+google-cloud-bigquery>=1.12.0
 future==0.16.0
+packaging>=20.0
 
 pytest==3.2.2
 pytz==2017.2

pybigquery/sqlalchemy_bigquery.py

@@ -3,12 +3,20 @@
 from __future__ import absolute_import
 from __future__ import unicode_literals
 
+import re
+import warnings
+from packaging.version import Version, parse as parse_version
+
 from google import auth
-from google.cloud import bigquery, bigquery_storage_v1beta1
-from google.cloud.bigquery import dbapi, QueryJobConfig
+from google.cloud import bigquery
+
+try:
+    from google.cloud import bigquery_storage_v1
+except ImportError:
+    pass
+
+from google.cloud.bigquery import dbapi
 from google.cloud.bigquery.schema import SchemaField
-from google.cloud.bigquery.table import EncryptionConfiguration
-from google.cloud.bigquery.dataset import DatasetReference
 from google.oauth2 import service_account
 from google.api_core.exceptions import NotFound
 from sqlalchemy.exc import NoSuchTableError
@@ -18,7 +26,6 @@
 from sqlalchemy.engine.base import Engine
 from sqlalchemy.sql.schema import Column
 from sqlalchemy.sql import elements
-import re
 
 from .parse_url import parse_url
 
@@ -342,11 +349,19 @@ def create_connect_args(self, url):
             default_query_job_config=default_query_job_config
         )
 
-        storage_client = None 
+        clients = [client]
+
         if use_bqstorage_api:
-            storage_client = bigquery_storage_v1beta1.BigQueryStorageClient(credentials=credentials)
+            if parse_version(bigquery.__version__) >= Version("1.26.0"):
+                try:
+                    storage_client = bigquery_storage_v1.BigQueryReadClient(credentials=credentials)
+                    clients.append(storage_client)
+                except NameError:
+                    warnings.warn("It is not possible to use the bqstorage api without installing the bqstorage extra requirement")
+            else:
+                warnings.warn('It is not possible to use the bqstorage api with google-cloud-bigquery < 1.26.0')
 
-        return ([client, storage_client], {})
+        return (clients, {})
 
     def _json_deserializer(self, row):
         """JSON deserializer for RECORD types.

setup.py

@@ -24,11 +24,18 @@ def readme():
         "Topic :: Database :: Front-Ends"
     ],
     install_requires=[
+        'google-cloud-bigquery>=1.12.0',
+        'packaging>=20.0'
         'sqlalchemy>=1.1.9',
-        'google-cloud-bigquery[bqstorage]>=1.25.0',
-        'google-cloud-bigquery-storage[fastavro]>=1.0.0',
         'future',
     ],
+    extras_require = {
+    "bqstorage": [
+        "google-cloud-bigquery-storage >= 1.0.0, <2.0.0dev",
+        "grpcio >= 1.8.2, < 2.0dev",
+        "pyarrow>=0.16.0, < 2.0dev",
+        ]
+    },
     tests_require=[
         'pytz'
     ],