Add more details to "no relevant sample found" warning log

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

src/frequenz/sdk/timeseries/_resampling.py

@@ -746,14 +746,46 @@ def resample(self, timestamp: datetime) -> Sample[Quantity]:
         # resort to some C (or similar) implementation.
         relevant_samples = list(itertools.islice(self._buffer, min_index, max_index))
         if not relevant_samples:
-            _logger.warning("No relevant samples found for: %s", self._name)
+            self._log_no_relevant_samples(minimum_relevant_timestamp, timestamp)
+
         value = (
             conf.resampling_function(relevant_samples, conf, props)
             if relevant_samples
             else None
         )
         return Sample(timestamp, None if value is None else Quantity(value))
 
+    def _log_no_relevant_samples(
+        self, minimum_relevant_timestamp: datetime, timestamp: datetime
+    ) -> None:
+        """Log that no relevant samples were found.
+
+        Args:
+            minimum_relevant_timestamp: The minimum timestamp for which relevant samples
+            timestamp: The timestamp for which no relevant samples were found.
+        """
+        if self._buffer:
+            buffer_label = f"Buffer({len(self._buffer)}):"
+            buffer_info = f"{self._buffer[0].timestamp} - {self._buffer[-1].timestamp}"
+        else:
+            buffer_label = "Buffer:"
+            buffer_info = "Buffer is empty"
+
+        # Calculate the maximum label width for alignment
+        label_width = max(len("Requested:"), len(buffer_label))
+
+        _logger.warning(
+            ("No relevant samples found for: %s\n%-*s %s - %s\n%-*s %s"),
+            self._name,
+            label_width,
+            "Requested:",
+            minimum_relevant_timestamp,
+            timestamp,
+            label_width,
+            buffer_label,
+            buffer_info,
+        )
+
 
 class _StreamingHelper:
     """Resample data coming from a source, sending the results to a sink."""