Add _to_trace_dict for image content and file content (#10989)

* Add _to_trace_dict for image content and file content

* update

Author: sjrl

haystack/dataclasses/chat_message.py

@@ -559,9 +559,9 @@ def _to_trace_dict(self) -> dict[str, Any]:
         for part in self._content:
             serialized_part = _serialize_content_part(part)
             if isinstance(part, ImageContent):
-                serialized_part["image"]["base64_image"] = f"Base64 string ({len(part.base64_image)} characters)"
+                serialized_part["image"] = part._to_trace_dict()
             elif isinstance(part, FileContent):
-                serialized_part["file"]["base64_data"] = f"Base64 string ({len(part.base64_data)} characters)"
+                serialized_part["file"] = part._to_trace_dict()
             serialized["content"].append(serialized_part)
 
         return serialized

haystack/dataclasses/file_content.py

@@ -84,6 +84,19 @@ def to_dict(self) -> dict[str, Any]:
         """
         return asdict(self)
 
+    def _to_trace_dict(self) -> dict[str, Any]:
+        """
+        Convert the FileContent to a dictionary representation for tracing.
+
+        The base64_data is replaced with a placeholder string to avoid sending large payloads to the tracing backend.
+
+        :returns:
+            Serialized version of the object only for tracing purposes.
+        """
+        data = self.to_dict()
+        data["base64_data"] = f"Base64 string ({len(self.base64_data)} characters)"
+        return data
+
     @classmethod
     def from_dict(cls, data: dict[str, Any]) -> "FileContent":
         """

haystack/dataclasses/image_content.py

@@ -142,6 +142,19 @@ def to_dict(self) -> dict[str, Any]:
         """
         return asdict(self)
 
+    def _to_trace_dict(self) -> dict[str, Any]:
+        """
+        Convert the ImageContent to a dictionary representation for tracing.
+
+        The base64_image is replaced with a placeholder string to avoid sending large payloads to the tracing backend.
+
+        :returns:
+            Serialized version of the object only for tracing purposes.
+        """
+        data = self.to_dict()
+        data["base64_image"] = f"Base64 string ({len(self.base64_image)} characters)"
+        return data
+
     @classmethod
     def from_dict(cls, data: dict[str, Any]) -> "ImageContent":
         """

releasenotes/notes/add-trace-dict-image-file-content-4b1ba2b8b1786294.yaml

@@ -0,0 +1,7 @@
+---
+enhancements:
+  - |
+    Add ``_to_trace_dict`` method to ``ImageContent`` and ``FileContent`` dataclasses.
+    When tracing is enabled, the large base64-encoded binary fields (``base64_image`` and ``base64_data``)
+    are replaced with placeholder strings (e.g. ``"Base64 string (N characters)"``),
+    consistent with the behavior of ``ByteStream._to_trace_dict``.

test/dataclasses/test_file_content.py

@@ -164,3 +164,14 @@ def test_file_content_warn_on_inplace_mutation():
     fc = FileContent(base64_data="dGVzdA==", mime_type="text/plain", validation=False)
     with pytest.warns(Warning, match="dataclasses.replace"):
         fc.mime_type = "application/pdf"
+
+
+def test_file_content_to_trace_dict(base64_pdf_string):
+    file_content = FileContent(
+        base64_data=base64_pdf_string, mime_type="application/pdf", filename="test.pdf", extra={"key": "value"}
+    )
+    data = file_content._to_trace_dict()
+    assert data["base64_data"] == f"Base64 string ({len(base64_pdf_string)} characters)"
+    assert data["mime_type"] == "application/pdf"
+    assert data["filename"] == "test.pdf"
+    assert data["extra"] == {"key": "value"}

test/dataclasses/test_image_content.py

@@ -235,3 +235,14 @@ def test_image_content_warn_on_inplace_mutation(base64_image_string):
     ic = ImageContent(base64_image=base64_image_string, mime_type="image/png")
     with pytest.warns(Warning, match="dataclasses.replace"):
         ic.detail = "high"
+
+
+def test_image_content_to_trace_dict(base64_image_string):
+    image_content = ImageContent(
+        base64_image=base64_image_string, mime_type="image/png", detail="auto", meta={"key": "value"}
+    )
+    data = image_content._to_trace_dict()
+    assert data["base64_image"] == f"Base64 string ({len(base64_image_string)} characters)"
+    assert data["mime_type"] == "image/png"
+    assert data["detail"] == "auto"
+    assert data["meta"] == {"key": "value"}