fix: The statistics page cannot display the tokens consumed by agent node (#21861)

api/core/model_runtime/entities/llm_entities.py

@@ -53,6 +53,37 @@ class LLMUsage(ModelUsage):
             latency=0.0,
         )
 
+    @classmethod
+    def from_metadata(cls, metadata: dict) -> "LLMUsage":
+        """
+        Create LLMUsage instance from metadata dictionary with default values.
+
+        Args:
+            metadata: Dictionary containing usage metadata
+
+        Returns:
+            LLMUsage instance with values from metadata or defaults
+        """
+        total_tokens = metadata.get("total_tokens", 0)
+        completion_tokens = metadata.get("completion_tokens", 0)
+        if total_tokens > 0 and completion_tokens == 0:
+            completion_tokens = total_tokens
+
+        return cls(
+            prompt_tokens=metadata.get("prompt_tokens", 0),
+            completion_tokens=completion_tokens,
+            total_tokens=total_tokens,
+            prompt_unit_price=Decimal(str(metadata.get("prompt_unit_price", 0))),
+            completion_unit_price=Decimal(str(metadata.get("completion_unit_price", 0))),
+            total_price=Decimal(str(metadata.get("total_price", 0))),
+            currency=metadata.get("currency", "USD"),
+            prompt_price_unit=Decimal(str(metadata.get("prompt_price_unit", 0))),
+            completion_price_unit=Decimal(str(metadata.get("completion_price_unit", 0))),
+            prompt_price=Decimal(str(metadata.get("prompt_price", 0))),
+            completion_price=Decimal(str(metadata.get("completion_price", 0))),
+            latency=metadata.get("latency", 0.0),
+        )
+
     def plus(self, other: "LLMUsage") -> "LLMUsage":
         """
         Add two LLMUsage instances together.