Make health check failures report their reasons

Note that we add a new block with expanded service info, to avoid breaking compatibility with existing callers of the health endpoint

data/buildlogs.py

@@ -120,15 +120,14 @@ class RedisBuildLogs(object):
 
       connection = redis.StrictRedis(**args)
       if not connection.ping() == True:
-        return False
+        return (False, 'Could not ping redis')
 
       # Ensure we can write and read a key.
       connection.set(self._health_key(), time.time())
       connection.get(self._health_key())
-
-      return True
-    except redis.RedisError:
-      return False
+      return (True, None)
+    except redis.RedisError as re:
+      return (False, 'Could not connect to redis: %s' % re.message)
 
 
 class BuildLogs(object):

data/model/health.py

@@ -11,12 +11,11 @@ def check_health(app_config):
   # check).
   try:
     validate_database_url(app_config['DB_URI'], {}, connect_timeout=3)
-  except Exception:
-    logger.exception('Could not connect to the database')
-    return False
+  except Exception as ex:
+    return (False, 'Could not connect to the database: %s', ex.message)
 
   # We will connect to the db, check that it contains some team role kinds
   try:
-    return bool(list(TeamRole.select().limit(1)))
-  except:
-    return False
+    return (bool(list(TeamRole.select().limit(1))), 'Could not connect to the database')
+  except Exception as ex:
+    return (False, 'Could not connect to the database: %s', ex.message)