feat: implement query_metrics

query_metrics currently has no implementation, meaning once a metric is emitted there is no way in llama stack to query it from the store.

implement query_metrics for the meta_reference provider which follows a similar style to `query_traces`, using the trace_store to format an SQL query and execute it

in this case the parameters for the query are `metric.METRIC_NAME, start_time, and end_time`.

this required client side changes since the client had no `query_metrics` or any associated resources, so any tests here will fail but I will provider manual execution logs for the new tests I am adding

order the metrics by timestamp.

Additionally add `unit` to the `MetricDataPoint` class since this adds much more context to the metric being queried.

these metrics can also be aggregated via a `granularity` parameter. This was pre-defined as a string like: `1m, 1h, 1d` where metrics occuring in same timespan specified are aggregated together.

Signed-off-by: Charlie Doern <cdoern@redhat.com>

llama_stack/providers/inline/telemetry/meta_reference/telemetry.py

@@ -4,6 +4,7 @@
 # This source code is licensed under the terms described in the LICENSE file in
 # the root directory of this source tree.
 
+import datetime
 import threading
 from typing import Any
 
@@ -145,11 +146,41 @@ class TelemetryAdapter(TelemetryDatasetMixin, Telemetry):
         metric_name: str,
         start_time: int,
         end_time: int | None = None,
-        granularity: str | None = "1d",
+        granularity: str | None = None,
         query_type: MetricQueryType = MetricQueryType.RANGE,
         label_matchers: list[MetricLabelMatcher] | None = None,
     ) -> QueryMetricsResponse:
-        raise NotImplementedError("Querying metrics is not implemented")
+        """Query metrics from the telemetry store.
+
+        Args:
+            metric_name: The name of the metric to query (e.g., "prompt_tokens")
+            start_time: Start time as Unix timestamp
+            end_time: End time as Unix timestamp (defaults to now if None)
+            granularity: Time granularity for aggregation
+            query_type: Type of query (RANGE or INSTANT)
+            label_matchers: Label filters to apply
+
+        Returns:
+            QueryMetricsResponse with metric time series data
+        """
+        # Convert timestamps to datetime objects
+        start_dt = datetime.datetime.fromtimestamp(start_time, datetime.UTC)
+        end_dt = datetime.datetime.fromtimestamp(end_time, datetime.UTC) if end_time else None
+
+        # Use SQLite trace store if available
+        if hasattr(self, "trace_store") and self.trace_store:
+            return await self.trace_store.query_metrics(
+                metric_name=metric_name,
+                start_time=start_dt,
+                end_time=end_dt,
+                granularity=granularity,
+                query_type=query_type,
+                label_matchers=label_matchers,
+            )
+        else:
+            raise ValueError(
+                f"In order to query_metrics, you must have {TelemetrySink.SQLITE} set in your telemetry sinks"
+            )
 
     def _log_unstructured(self, event: UnstructuredLogEvent, ttl_seconds: int) -> None:
         with self._lock: