[Serve] add RAY_SERVE_LOG_ENCODING env to set the global logging be…

…havior for Serve (ray-project#42781)

We want a way to be able to use environment variables to setup Serve's structured json logging. Add `RAY_SERVE_LOG_ENCODING_ENV` env to set the global logging behavior for Serve.

---------

Signed-off-by: Gene Su <[email protected]>

python/ray/serve/_private/constants.py

@@ -163,8 +163,13 @@
     "instead (see https://docs.ray.io/en/latest/serve/model_composition.html)."
 )
 
-# Jsonify the log messages
+# Environment variable name for to specify the encoding of the log messages
+RAY_SERVE_LOG_ENCODING = os.environ.get("RAY_SERVE_LOG_ENCODING", "TEXT")
+
+# Jsonify the log messages. This constant is deprecated and will be removed in the
+# future. Use RAY_SERVE_LOG_ENCODING or 'LoggingConfig' to enable json format.
 RAY_SERVE_ENABLE_JSON_LOGGING = os.environ.get("RAY_SERVE_ENABLE_JSON_LOGGING") == "1"
+
 # Logging format attributes
 SERVE_LOG_REQUEST_ID = "request_id"
 SERVE_LOG_ROUTE = "route"

python/ray/serve/_private/logging_utils.py

@@ -189,6 +189,8 @@ def configure_component_logger(
     component_id: str,
     logging_config: LoggingConfig,
     component_type: Optional[ServeComponentType] = None,
+    max_bytes: Optional[int] = None,
+    backup_count: Optional[int] = None,
 ):
     """Configure a logger to be used by a Serve component.
 
@@ -228,8 +230,10 @@ def record_factory(*args, **kwargs):
         logs_dir = get_serve_logs_dir()
     os.makedirs(logs_dir, exist_ok=True)
 
-    max_bytes = ray._private.worker._global_node.max_bytes
-    backup_count = ray._private.worker._global_node.backup_count
+    if max_bytes is None:
+        max_bytes = ray._private.worker._global_node.max_bytes
+    if backup_count is None:
+        backup_count = ray._private.worker._global_node.backup_count
 
     log_file_name = get_component_log_file_name(
         component_name=component_name,

python/ray/serve/schema.py

@@ -26,6 +26,7 @@
 from ray.serve._private.constants import (
     DEFAULT_GRPC_PORT,
     DEFAULT_UVICORN_KEEP_ALIVE_TIMEOUT_S,
+    RAY_SERVE_LOG_ENCODING,
     SERVE_DEFAULT_APP_NAME,
 )
 from ray.serve._private.deployment_info import DeploymentInfo
@@ -130,10 +131,11 @@ class Config:
         extra = Extra.forbid
 
     encoding: Union[str, EncodingType] = Field(
-        default="TEXT",
+        default_factory=lambda: RAY_SERVE_LOG_ENCODING,
         description=(
-            "Encoding type for the serve logs. Default to 'TEXT'. 'JSON' is also "
-            "supported to format all serve logs into json structure."
+            "Encoding type for the serve logs. Defaults to 'TEXT'. The default can be "
+            "overwritten using the `RAY_SERVE_LOG_ENCODING` environment variable. "
+            "'JSON' is also supported for structured logging."
         ),
     )
     log_level: Union[int, str] = Field(

python/ray/serve/tests/test_logging.py

@@ -7,6 +7,7 @@
 import sys
 import time
 from contextlib import redirect_stderr
+from unittest.mock import patch
 
 import pytest
 import requests
@@ -17,12 +18,15 @@
 from ray import serve
 from ray._private.test_utils import wait_for_condition
 from ray.serve._private.common import ServeComponentType
-from ray.serve._private.constants import SERVE_LOG_EXTRA_FIELDS
+from ray.serve._private.constants import SERVE_LOG_EXTRA_FIELDS, SERVE_LOGGER_NAME
 from ray.serve._private.logging_utils import (
+    ServeFormatter,
     ServeJSONFormatter,
+    configure_component_logger,
     get_component_log_file_name,
     get_serve_logs_dir,
 )
+from ray.serve.schema import EncodingType, LoggingConfig
 
 
 @pytest.fixture
@@ -578,5 +582,67 @@ def format_and_verify_json_output(record, expected_record: dict):
     format_and_verify_json_output(record, expected_json)
 
 
+@pytest.mark.parametrize(
+    "log_encoding",
+    [
+        [None, None, "TEXT"],
+        [None, "TEXT", "TEXT"],
+        [None, "JSON", "JSON"],
+        ["TEXT", None, "TEXT"],
+        ["TEXT", "TEXT", "TEXT"],
+        ["TEXT", "JSON", "JSON"],
+        ["JSON", None, "JSON"],
+        ["JSON", "TEXT", "TEXT"],
+        ["JSON", "JSON", "JSON"],
+        ["FOOBAR", None, "TEXT"],
+        ["FOOBAR", "TEXT", "TEXT"],
+        ["FOOBAR", "JSON", "JSON"],
+    ],
+)
+def test_configure_component_logger_with_log_encoding_env_text(log_encoding):
+    """Test the configure_component_logger function with different log encoding env.
+
+    When the log encoding env is not set, set to "TEXT" or set to unknon values,
+    the ServeFormatter should be used. When the log encoding env is set to "JSON",
+    the ServeJSONFormatter should be used. Also, the log config should take the
+    precedence it's set.
+    """
+    env_encoding, log_config_encoding, expected_encoding = log_encoding
+
+    with patch("ray.serve.schema.RAY_SERVE_LOG_ENCODING", env_encoding):
+
+        # Clean up logger handlers
+        logger = logging.getLogger(SERVE_LOGGER_NAME)
+        logger.handlers.clear()
+
+        # Ensure there is no logger handlers before calling configure_component_logger
+        assert logger.handlers == []
+
+        if log_config_encoding is None:
+            logging_config = LoggingConfig(logs_dir="/tmp/fake_logs_dir")
+        else:
+            logging_config = LoggingConfig(
+                encoding=log_config_encoding, logs_dir="/tmp/fake_logs_dir"
+            )
+        configure_component_logger(
+            component_name="fake_component_name",
+            component_id="fake_component_id",
+            logging_config=logging_config,
+            component_type=ServeComponentType.REPLICA,
+            max_bytes=100,
+            backup_count=3,
+        )
+
+        for handler in logger.handlers:
+            if isinstance(handler, logging.handlers.RotatingFileHandler):
+                if expected_encoding == EncodingType.JSON:
+                    assert isinstance(handler.formatter, ServeJSONFormatter)
+                else:
+                    assert isinstance(handler.formatter, ServeFormatter)
+
+        # Clean up logger handlers
+        logger.handlers.clear()
+
+
 if __name__ == "__main__":
     sys.exit(pytest.main(["-v", "-s", __file__]))