Allow creation of Metric from data structure without __name__ (#306)

* Allow creation of Metric from datastructure without __name__

When applying a function to a time series in a query to Prometheus,
the Prometheus server returns a data structure without __name__ key.
Apart from that aspect, the time series could still be used to create
a Metric object.

This PR proposes to set "metric_name" to None when __name__ is missing.

* Update prometheus_api_client/metric.py

Co-authored-by: Copilot <[email protected]>

---------

Co-authored-by: Anand Sanmukhani <[email protected]>
Co-authored-by: Copilot <[email protected]>

Author: 3 people

prometheus_api_client/metric.py

@@ -54,10 +54,11 @@ def __init__(self, metric, oldest_data_datetime=None):
             self.metric_values = metric.metric_values
             self.oldest_data_datetime = oldest_data_datetime
         else:
-            self.metric_name = metric["metric"]["__name__"]
+            self.metric_name = metric["metric"].get("__name__", None)
             self.label_config = deepcopy(metric["metric"])
+            if "__name__" in self.label_config:
+                del self.label_config["__name__"]
             self.oldest_data_datetime = oldest_data_datetime
-            del self.label_config["__name__"]
 
             # if it is a single value metric change key name
             if "value" in metric: