Have the config setup tool automatically prepare the S3 or GCS storage with CORS config

storage/basestorage.py

@@ -54,6 +54,10 @@ class BaseStorage(StoragePaths):
   # Set the IO buffer to 64kB
   buffer_size = 64 * 1024
 
+  def setup(self):
+    """ Called to perform any storage system setup. """
+    pass
+
   def get_direct_download_url(self, path, expires_in=60, requires_cors=False):
     return None
 

storage/cloud.py

@@ -77,6 +77,13 @@ class _CloudStorage(BaseStorage):
       return path[1:]
     return path
 
+  def get_cloud_conn(self):
+    self._initialize_cloud_conn()
+    return self._cloud_conn
+
+  def get_cloud_bucket(self):
+    return self._cloud_bucket
+
   def get_content(self, path):
     self._initialize_cloud_conn()
     path = self._init_path(path)
@@ -221,6 +228,25 @@ class S3Storage(_CloudStorage):
                                     connect_kwargs, upload_params, storage_path, s3_access_key,
                                     s3_secret_key, s3_bucket)
 
+  def setup(self):
+    self.get_cloud_bucket().set_cors_xml("""<?xml version="1.0" encoding="UTF-8"?>
+      <CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
+          <CORSRule>
+              <AllowedOrigin>*</AllowedOrigin>
+              <AllowedMethod>GET</AllowedMethod>
+              <MaxAgeSeconds>3000</MaxAgeSeconds>
+              <AllowedHeader>Authorization</AllowedHeader>
+          </CORSRule>
+          <CORSRule>
+              <AllowedOrigin>*</AllowedOrigin>
+              <AllowedMethod>PUT</AllowedMethod>
+              <MaxAgeSeconds>3000</MaxAgeSeconds>
+              <AllowedHeader>Content-Type</AllowedHeader>
+              <AllowedHeader>x-amz-acl</AllowedHeader>
+              <AllowedHeader>origin</AllowedHeader>
+          </CORSRule>
+      </CORSConfiguration>""")
+
 
 class GoogleCloudStorage(_CloudStorage):
   def __init__(self, storage_path, access_key, secret_key, bucket_name):
@@ -230,6 +256,24 @@ class GoogleCloudStorage(_CloudStorage):
                                              connect_kwargs, upload_params, storage_path,
                                              access_key, secret_key, bucket_name)
 
+  def setup(self):
+    self.get_cloud_bucket().set_cors_xml("""<?xml version="1.0" encoding="UTF-8"?>
+      <CorsConfig>
+        <Cors>
+          <Origins>
+            <Origin>*</Origin>
+          </Origins>
+          <Methods>
+            <Method>GET</Method>
+            <Method>PUT</Method>
+          </Methods>
+          <ResponseHeaders>
+            <ResponseHeader>Content-Type</ResponseHeader>
+          </ResponseHeaders>
+          <MaxAgeSec>3000</MaxAgeSec>
+        </Cors>
+      </CorsConfig>""")
+
   def stream_write(self, path, fp, content_type=None, content_encoding=None):
     # Minimum size of upload part size on S3 is 5MB
     self._initialize_cloud_conn()

util/config/validator.py

@@ -15,6 +15,13 @@ from util.oauth import GoogleOAuthConfig, GithubOAuthConfig
 
 SSL_FILENAMES = ['ssl.cert', 'ssl.key']
 
+def get_storage_provider(config):
+  parameters = config.get('DISTRIBUTED_STORAGE_CONFIG', {}).get('local', ['LocalStorage', {}])
+  try:
+    return get_storage_driver(parameters)
+  except TypeError:
+    raise Exception('Missing required storage configuration parameter(s)')
+
 def validate_service_for_config(service, config):
   """ Attempts to validate the configuration for the given service. """
   if not service in _VALIDATORS:
@@ -57,16 +64,18 @@ def _validate_redis(config):
 
 def _validate_registry_storage(config):
   """ Validates registry storage. """
-  parameters = config.get('DISTRIBUTED_STORAGE_CONFIG', {}).get('local', ['LocalStorage', {}])
+  driver = get_storage_provider(config)
-  try:
-    driver = get_storage_driver(parameters)
-  except TypeError:
-    raise Exception('Missing required storage configuration parameter(s)')
 
   # Put and remove a temporary file.
   driver.put_content('_verify', 'testing 123')
   driver.remove('_verify')
 
+  # Run setup on the driver if the read/write succeeded.
+  try:
+    driver.setup()
+  except Exception as ex:
+    raise Exception('Could not prepare storage: %s' % str(ex))
+
 
 def _validate_mailing(config):
   """ Validates sending email. """