only connect to pandora as needed

etc/systemd/system/dd-re.service

@@ -7,7 +7,6 @@ Restart=always
 User=dd
 Group=dd
 WorkingDirectory=/srv/dd/re
-ExecStartPre=/usr/bin/wait-for-it -h pandora.dmp -p 80
 ExecStart=/srv/dd/re/server.py
 
 [Install]

recommendation_engine.py

@@ -5,18 +5,24 @@ Recommendation Engine Example
 
 from collections import defaultdict
 import json
+import logging
 import os
 import random
+import time
 
 import ox
 
 from utils import run_async
 
+logger = logging.getLogger(__name__)
+
+
 class Engine:
+    _pandora = None
 
     def __init__(self, path, **kwargs):
         self.path = path
-        self.pandora = Pandora(
+        self.pandora_args = dict(
             url=kwargs.get('pandora', 'http://pandora.dmp/api/'),
             username=kwargs.get('username', 'dd.re'),
             password=kwargs.get('password', 'dd.re')
@@ -28,6 +34,16 @@ class Engine:
         else:
             self.playlists = []
 
+    @property
+    def pandora(self):
+        while not self._pandora:
+            try:
+                self._pandora = Pandora(**self.pandora_args)
+            except:
+                logger.error('failed to connect to pandora, retry in 10 seconds')
+                time.sleep(10)
+        return self._pandora
+
     def _patch_clips(self, clips):
         inpoints = {}
         for index, clip in enumerate(clips):