Update the body type in the log (#3343)

Co-authored-by: Shalev Roda <65566801+shalevr@users.noreply.github.com>
Co-authored-by: Srikanth Chekuri <srikanth.chekuri92@gmail.com>

CHANGELOG.md

@@ -7,7 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
-
+- Update the body type in the log
+  ([$3343](https://github.com/open-telemetry/opentelemetry-python/pull/3343))
 - Add max_scale option to Exponential Bucket Histogram Aggregation 
   ([#3323](https://github.com/open-telemetry/opentelemetry-python/pull/3323))
 - Use BoundedAttributes instead of raw dict to extract attributes from LogRecord
@@ -23,6 +24,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed bug where logging export is tracked as trace
   [#3375](https://github.com/open-telemetry/opentelemetry-python/pull/3375))
 
+
 ## Version 1.18.0/0.39b0 (2023-05-19)
 
 - Select histogram aggregation with an environment variable

opentelemetry-sdk/src/opentelemetry/sdk/_logs/_internal/__init__.py

@@ -21,7 +21,7 @@
 import traceback
 from os import environ
 from time import time_ns
-from typing import Any, Callable, Optional, Tuple, Union
+from typing import Any, Callable, Optional, Tuple, Union  # noqa
 
 from opentelemetry._logs import Logger as APILogger
 from opentelemetry._logs import LoggerProvider as APILoggerProvider
@@ -476,15 +476,56 @@ def _translate(self, record: logging.LogRecord) -> LogRecord:
         timestamp = int(record.created * 1e9)
         span_context = get_current_span().get_span_context()
         attributes = self._get_attributes(record)
+        # This comment is taken from GanyedeNil's PR #3343, I have redacted it
+        # slightly for clarity:
+        # According to the definition of the Body field type in the
+        # OTel 1.22.0 Logs Data Model article, the Body field should be of
+        # type 'any' and should not use the str method to directly translate
+        # the msg. This is because str only converts non-text types into a
+        # human-readable form, rather than a standard format, which leads to
+        # the need for additional operations when collected through a log
+        # collector.
+        # Considering that he Body field should be of type 'any' and should not
+        # use the str method but record.msg is also a string type, then the
+        # difference is just the self.args formatting?
+        # The primary consideration depends on the ultimate purpose of the log.
+        # Converting the default log directly into a string is acceptable as it
+        # will be required to be presented in a more readable format. However,
+        # this approach might not be as "standard" when hoping to aggregate
+        # logs and perform subsequent data analysis. In the context of log
+        # extraction, it would be more appropriate for the msg to be
+        # converted into JSON format or remain unchanged, as it will eventually
+        # be transformed into JSON. If the final output JSON data contains a
+        # structure that appears similar to JSON but is not, it may confuse
+        # users. This is particularly true for operation and maintenance
+        # personnel who need to deal with log data in various languages.
+        # Where is the JSON converting occur? and what about when the msg
+        # represents something else but JSON, the expected behavior change?
+        # For the ConsoleLogExporter, it performs the to_json operation in
+        # opentelemetry.sdk._logs._internal.export.ConsoleLogExporter.__init__,
+        # so it can handle any type of input without problems. As for the
+        # OTLPLogExporter, it also handles any type of input encoding in
+        # _encode_log located in
+        # opentelemetry.exporter.otlp.proto.common._internal._log_encoder.
+        # Therefore, no extra operation is needed to support this change.
+        # The only thing to consider is the users who have already been using
+        # this SDK. If they upgrade the SDK after this change, they will need
+        # to readjust their logging collection rules to adapt to the latest
+        # output format. Therefore, this change is considered a breaking
+        # change and needs to be upgraded at an appropriate time.
         severity_number = std_to_otel(record.levelno)
+        if isinstance(record.msg, str) and record.args:
+            body = record.msg % record.args
+        else:
+            body = record.msg
         return LogRecord(
             timestamp=timestamp,
             trace_id=span_context.trace_id,
             span_id=span_context.span_id,
             trace_flags=span_context.trace_flags,
             severity_text=record.levelname,
             severity_number=severity_number,
-            body=record.getMessage(),
+            body=body,
             resource=self._logger.resource,
             attributes=attributes,
         )

opentelemetry-sdk/tests/logs/test_export.py

@@ -173,6 +173,40 @@ def test_simple_log_record_processor_shutdown(self):
         finished_logs = exporter.get_finished_logs()
         self.assertEqual(len(finished_logs), 0)
 
+    def test_simple_log_record_processor_different_msg_types(self):
+        exporter = InMemoryLogExporter()
+        log_record_processor = BatchLogRecordProcessor(exporter)
+
+        provider = LoggerProvider()
+        provider.add_log_record_processor(log_record_processor)
+
+        logger = logging.getLogger("different_msg_types")
+        logger.addHandler(LoggingHandler(logger_provider=provider))
+
+        logger.warning("warning message: %s", "possible upcoming heatwave")
+        logger.error("Very high rise in temperatures across the globe")
+        logger.critical("Temperature hits high 420 C in Hyderabad")
+        logger.warning(["list", "of", "strings"])
+        logger.error({"key": "value"})
+        log_record_processor.shutdown()
+
+        finished_logs = exporter.get_finished_logs()
+        expected = [
+            ("warning message: possible upcoming heatwave", "WARNING"),
+            ("Very high rise in temperatures across the globe", "ERROR"),
+            (
+                "Temperature hits high 420 C in Hyderabad",
+                "CRITICAL",
+            ),
+            (["list", "of", "strings"], "WARNING"),
+            ({"key": "value"}, "ERROR"),
+        ]
+        emitted = [
+            (item.log_record.body, item.log_record.severity_text)
+            for item in finished_logs
+        ]
+        self.assertEqual(expected, emitted)
+
 
 class TestBatchLogRecordProcessor(ConcurrencyTestBase):
     def test_emit_call_log_record(self):