opamp-client: support text effective config bodies

opamp/opentelemetry-opamp-client/.changelog/4536.added

@@ -0,0 +1 @@
+`opentelemetry-opamp-client`: support non-JSON effective config bodies

opamp/opentelemetry-opamp-client/src/opentelemetry/_opamp/client.py

@@ -4,7 +4,7 @@
 from __future__ import annotations
 
 from logging import getLogger
-from typing import Generator, Mapping
+from typing import Any, Generator, Mapping
 
 from uuid_utils import uuid7
 
@@ -98,7 +98,9 @@ def build_heartbeat_message(self) -> bytes:
         return data
 
     def update_effective_config(
-        self, effective_config: dict[str, dict[str, str]], content_type: str
+        self,
+        effective_config: Mapping[str, Any],
+        content_type: str,
     ) -> opamp_pb2.EffectiveConfig:
         self._effective_config = messages.build_effective_config_message(
             config=effective_config, content_type=content_type

opamp/opentelemetry-opamp-client/src/opentelemetry/_opamp/messages.py

@@ -6,7 +6,8 @@
 from __future__ import annotations
 
 import json
-from typing import Generator, Mapping
+from logging import getLogger
+from typing import Any, Generator, Mapping
 
 from opentelemetry._opamp.exceptions import (
     OpAMPRemoteConfigDecodeException,
@@ -21,6 +22,8 @@
 )
 from opentelemetry.util.types import AnyValue
 
+_logger = getLogger(__name__)
+
 
 def decode_message(data: bytes) -> opamp_pb2.ServerToAgent:
     message = opamp_pb2.ServerToAgent()
@@ -119,19 +122,47 @@ def build_remote_config_status_response_message(
 
 
 def build_effective_config_message(
-    config: dict[str, dict[str, str]], content_type: str
+    config: Mapping[str, Any], content_type: str
 ):
     agent_config_map = opamp_pb2.AgentConfigMap()
     for filename, value in config.items():
-        if content_type == "application/json":
-            body = json.dumps(value)
-            agent_config_map.config_map[filename].body = body.encode("utf-8")
-            agent_config_map.config_map[filename].content_type = content_type
+        body = encode_effective_config_body(content_type, value)
+        if body is None:
+            _logger.warning(
+                "Skipping effective config entry %s with content type %s "
+                "because the value cannot be encoded",
+                filename,
+                content_type,
+            )
+            continue
+
+        config_entry = agent_config_map.config_map[filename]
+        config_entry.body = body
+        config_entry.content_type = content_type
     return opamp_pb2.EffectiveConfig(
         config_map=agent_config_map,
     )
 
 
+def encode_effective_config_body(
+    content_type: str, value: Any
+) -> bytes | None:
+    if content_type == "application/json":
+        try:
+            return json.dumps(value).encode("utf-8")
+        except (TypeError, ValueError):
+            _logger.warning(
+                "Failed to encode effective config body as JSON",
+                exc_info=True,
+            )
+            return None
+    if isinstance(value, str):
+        return value.encode("utf-8")
+    if isinstance(value, bytes):
+        return value
+    return None
+
+
 def build_full_state_message(
     instance_uid: bytes,
     sequence_num: int,

opamp/opentelemetry-opamp-client/tests/opamp/test_client.py

@@ -4,6 +4,7 @@
 # pylint: disable=no-name-in-module
 
 import json
+import logging
 from unittest import mock
 
 import pytest
@@ -307,6 +308,68 @@ def test_update_effective_config_json_content_type(client):
     assert config == decoded_config
 
 
+def test_update_effective_config_skips_non_serializable_json_content(
+    client, caplog
+):
+    caplog.set_level(logging.WARNING, logger="opentelemetry._opamp.messages")
+    effective_config = client.update_effective_config(
+        {"config": {"a": object()}},
+        content_type="application/json",
+    )
+    assert effective_config.config_map.config_map == {}
+    message = "Failed to encode effective config body as JSON"
+    exception_records = [
+        record for record in caplog.records if message in record.getMessage()
+    ]
+    assert len(exception_records) == 1
+    assert exception_records[0].exc_info
+    assert exception_records[0].exc_info[0] is TypeError
+    assert "Skipping effective config entry config" in caplog.text
+
+
+def test_update_effective_config_text_content_type(client):
+    config = {"config": "FEATURE_ENABLED=false\n"}
+    effective_config = client.update_effective_config(
+        config,
+        content_type="text/plain",
+    )
+    config_entry = effective_config.config_map.config_map["config"]
+    assert config_entry.content_type == "text/plain"
+    assert config_entry.body == b"FEATURE_ENABLED=false\n"
+
+
+def test_update_effective_config_bytes_content(client):
+    config = {"config": b"FEATURE_ENABLED=false\n"}
+    effective_config = client.update_effective_config(
+        config,
+        content_type="text/plain",
+    )
+    config_entry = effective_config.config_map.config_map["config"]
+    assert config_entry.content_type == "text/plain"
+    assert config_entry.body == b"FEATURE_ENABLED=false\n"
+
+
+def test_update_effective_config_skips_unencodable_content(client, caplog):
+    caplog.set_level(logging.WARNING, logger="opentelemetry._opamp.messages")
+    effective_config = client.update_effective_config(
+        {"config": {"a": "config"}},
+        content_type="text/plain",
+    )
+    assert effective_config.config_map.config_map == {}
+    assert "Skipping effective config entry config" in caplog.text
+
+
+def test_build_full_state_message_text_effective_config(client):
+    config = {"config": "FEATURE_ENABLED=false\n"}
+    client.update_effective_config(config, content_type="text/plain")
+    data = client.build_full_state_message()
+    message = opamp_pb2.AgentToServer()
+    message.ParseFromString(data)
+    config_entry = message.effective_config.config_map.config_map["config"]
+    assert config_entry.content_type == "text/plain"
+    assert config_entry.body == b"FEATURE_ENABLED=false\n"
+
+
 def test_build_full_state_message(client):
     client.update_remote_config_status(
         remote_config_hash=b"12345678",