feat: added cached token metrics -metrics

Author: poshinchen

src/strands/telemetry/metrics.py

@@ -11,7 +11,7 @@
 
 from ..telemetry import metrics_constants as constants
 from ..types.content import Message
-from ..types.streaming import Metrics, Usage
+from ..types.event_loop import Metrics, Usage
 from ..types.tools import ToolUse
 
 logger = logging.getLogger(__name__)
@@ -265,21 +265,19 @@ def update_usage(self, usage: Usage) -> None:
         self.accumulated_usage["totalTokens"] += usage["totalTokens"]
 
         # Handle optional cached token metrics
-        if "cacheReadInputTokens" in usage and usage["cacheReadInputTokens"] is not None:
+        if "cacheReadInputTokens" in usage:
             cache_read_tokens = usage["cacheReadInputTokens"]
-            self._metrics_client.event_loop_cache_read_tokens.record(cache_read_tokens)
-            if "cacheReadInputTokens" not in self.accumulated_usage:
-                self.accumulated_usage["cacheReadInputTokens"] = 0
-            current_cache_read = self.accumulated_usage.get("cacheReadInputTokens", 0) or 0
-            self.accumulated_usage["cacheReadInputTokens"] = current_cache_read + cache_read_tokens
+            self._metrics_client.event_loop_cache_read_input_tokens.record(cache_read_tokens)
+            self.accumulated_usage["cacheReadInputTokens"] = (
+                self.accumulated_usage.get("cacheReadInputTokens", 0) + cache_read_tokens
+            )
 
-        if "cacheWriteInputTokens" in usage and usage["cacheWriteInputTokens"] is not None:
+        if "cacheWriteInputTokens" in usage:
             cache_write_tokens = usage["cacheWriteInputTokens"]
-            self._metrics_client.event_loop_cache_write_tokens.record(cache_write_tokens)
-            if "cacheWriteInputTokens" not in self.accumulated_usage:
-                self.accumulated_usage["cacheWriteInputTokens"] = 0
-            current_cache_write = self.accumulated_usage.get("cacheWriteInputTokens", 0) or 0
-            self.accumulated_usage["cacheWriteInputTokens"] = current_cache_write + cache_write_tokens
+            self._metrics_client.event_loop_cache_write_input_tokens.record(cache_write_tokens)
+            self.accumulated_usage["cacheWriteInputTokens"] = (
+                self.accumulated_usage.get("cacheWriteInputTokens", 0) + cache_write_tokens
+            )
 
     def update_metrics(self, metrics: Metrics) -> None:
         """Update the accumulated performance metrics with new metrics data.
@@ -448,8 +446,8 @@ class MetricsClient:
     event_loop_latency: Histogram
     event_loop_input_tokens: Histogram
     event_loop_output_tokens: Histogram
-    event_loop_cache_read_tokens: Histogram
-    event_loop_cache_write_tokens: Histogram
+    event_loop_cache_read_input_tokens: Histogram
+    event_loop_cache_write_input_tokens: Histogram
 
     tool_call_count: Counter
     tool_success_count: Counter
@@ -503,9 +501,9 @@ def create_instruments(self) -> None:
         self.event_loop_output_tokens = self.meter.create_histogram(
             name=constants.STRANDS_EVENT_LOOP_OUTPUT_TOKENS, unit="token"
         )
-        self.event_loop_cache_read_tokens = self.meter.create_histogram(
-            name=constants.STRANDS_EVENT_LOOP_CACHE_READ_TOKENS, unit="token"
+        self.event_loop_cache_read_input_tokens = self.meter.create_histogram(
+            name=constants.STRANDS_EVENT_LOOP_CACHE_READ_INPUT_TOKENS, unit="token"
         )
-        self.event_loop_cache_write_tokens = self.meter.create_histogram(
-            name=constants.STRANDS_EVENT_LOOP_CACHE_WRITE_TOKENS, unit="token"
+        self.event_loop_cache_write_input_tokens = self.meter.create_histogram(
+            name=constants.STRANDS_EVENT_LOOP_CACHE_WRITE_INPUT_TOKENS, unit="token"
         )