feat(metrics): store dimensions alongside metrics in store_data

In d6e5521b we added a metrics.json to dump all emitted metrics, but we
don't add the dimensions to easily parse and know to know to what they
refer.
This patch changes the format of the metrics.json to add two keys:
metrics, contanining the old dict of metrics, and dimensions,
contiaining the dict of dimensions.
We're not storing all other properties as they are the same across all
tests on the same executor and they can be fetched from test_result.json
already, under "user_properties".

Signed-off-by: Riccardo Mancini <[email protected]>

Author: Manciukic

tests/host_tools/metrics.py

@@ -57,19 +57,25 @@ class MetricsWrapper:
     """A convenient metrics logger"""
 
     def __init__(self, logger):
-        self.data = {}
+        self.metrics = {}
+        self.dimensions = {}
         self.logger = logger
 
-    def set_dimensions(self, *args, **kwargs):
+    def set_dimensions(self, *dimensions, **kwargs):
         """Set dimensions"""
         if self.logger:
-            self.logger.set_dimensions(*args, **kwargs)
+            self.logger.set_dimensions(*dimensions, **kwargs)
+
+        self.dimensions = {}
+        for dimension_dict in dimensions:
+            for k, v in dimension_dict.items():
+                self.dimensions[k] = v
 
     def put_metric(self, name, data, unit):
         """Put a datapoint with given dimensions"""
-        if name not in self.data:
-            self.data[name] = {"unit": unit, "values": []}
-        self.data[name]["values"].append(data)
+        if name not in self.metrics:
+            self.metrics[name] = {"unit": unit, "values": []}
+        self.metrics[name]["values"].append(data)
 
         if self.logger:
             self.logger.put_metric(name, data, unit)
@@ -88,7 +94,13 @@ def store_data(self, dir_path):
         """Store data into a file"""
         metrics_path = Path(dir_path / "metrics.json")
         with open(metrics_path, "w", encoding="utf-8") as f:
-            json.dump(self.data, f)
+            json.dump(
+                {
+                    "metrics": self.metrics,
+                    "dimensions": self.dimensions,
+                },
+                f,
+            )
 
 
 def get_metrics_logger():