Make zencoder and algolia optional packages

If zencoder is not set as ENCODING_BACKEND this can cause issues, but
at least it is possible to run Pillar without the zencoder package
installed. Also, we load the algolia module using the new
SEARCH_BACKEND config setting.

pillar/application/__init__.py

@@ -4,7 +4,6 @@ import os
 import tempfile
 from bson import ObjectId
 from datetime import datetime
-from zencoder import Zencoder
 from flask import g
 from flask import request
 from flask import abort
@@ -137,7 +136,7 @@ except KeyError:
     raise SystemExit('GCLOUD_PROJECT configuration value is missing')
 
 # Algolia search
-if 'ALGOLIA_USER' in app.config:
+if app.config['SEARCH_BACKEND'] == 'algolia':
     from algoliasearch import algoliasearch
 
     client = algoliasearch.Client(
@@ -151,6 +150,7 @@ else:
 
 # Encoding backend
 if app.config['ENCODING_BACKEND'] == 'zencoder':
+    from zencoder import Zencoder
     encoding_service_client = Zencoder(app.config['ZENCODER_API_KEY'])
 else:
     encoding_service_client = None

pillar/application/utils/encoding.py

@@ -2,7 +2,6 @@ import logging
 import os
 
 from flask import current_app
-from zencoder import Zencoder
 
 from application import encoding_service_client
 
@@ -18,13 +17,13 @@ class Encoder:
     def job_create(src_file):
         """Create an encoding job. Return the backend used as well as an id.
         """
-
-        if not isinstance(encoding_service_client, Zencoder):
-            log.error('I can only work with Zencoder, not with %r', encoding_service_client)
+        if current_app.config['ENCODING_BACKEND'] != 'zencoder' or \
+                encoding_service_client is None:
+            log.error('I can only work with Zencoder, check the config file.')
             return None
 
         if src_file['backend'] != 'gcs':
-            log.error("Unable to work with storage backend %r", src_file['backend'])
+            log.error('Unable to work with storage backend %r', src_file['backend'])
             return None
 
         # Build the specific GCS input url, assuming the file is stored

pillar/config.py

@@ -51,6 +51,8 @@ ALGOLIA_API_KEY = '-SECRET-'
 ALGOLIA_INDEX_USERS = 'dev_Users'
 ALGOLIA_INDEX_NODES = 'dev_Nodes'
 
+SEARCH_BACKEND = 'algolia'  # algolia, elastic
+
 ZENCODER_API_KEY = '-SECRET-'
 ZENCODER_NOTIFICATIONS_SECRET = '-SECRET-'
 ZENCODER_NOTIFICATIONS_URL = 'http://zencoderfetcher/'