add loki realtime logging

pilot/util/realtimelogger.py

@@ -179,7 +179,8 @@ def __init__(self, args, info_dic, workdir, secrets, level=INFO):
                     transport=transport,
                     database_path='logstash_test.db'
                 )
-
+            elif logtype == 'loki':
+                _handler = self.setup_loki_handler()
             else:
                 logger.warning(f'unknown logtype: {logtype}')
                 _handler = None
@@ -194,6 +195,41 @@ def __init__(self, args, info_dic, workdir, secrets, level=INFO):
             RealTimeLogger.glogger = None
             del self
 
+    def setup_loki_handler(self):
+        from loki_logger_handler.loki_logger_handler import LokiLoggerHandler
+
+        loki_labels = {'application': 'PanDA_Pilot', 'envirnment': 'Production'}
+        try:
+            labels = os.environ.get('LOKI_LABELS', {})
+            if labels:
+                labels = json.loads(labels)
+                loki_labels = labels
+        except Exception as ex:
+            logger.warning(f'failed to load LOKI_LABELS from environment: {ex}')
+
+        loki_labelkeys = ['application', 'environment']
+        try:
+            labelkeys = os.environ.get('LOKI_LABELKEYS', {})
+            if labelkeys:
+                labelkeys = json.loads(labelkeys)
+                loki_labelkeys = labelkeys
+        except Exception as ex:
+            logger.warning(f'failed to load LOKI_LABELKEYS from environment: {ex}')
+
+        try:
+            loki_period = int(os.environ.get('LOKI_PERIOD', 30))
+        except Exception as ex:
+            logger.warning(f'failed to load LOKI_PERIOD from environment: {ex}')
+            loki_period = 30
+
+        _handler = LokiLoggerHandler(
+            url=os.environ["LOKI_URL"],
+            labels=loki_labels,
+            labelKeys=loki_labelkeys,
+            timeout=loki_period
+        )
+        return _handler
+
     def cleanup(self):
         """
         Clean-up.