[Python] Add flag to disable logging config (#3060)

Fixes #2780

This adds a environment variable `MLC_UNSET_LOGGING` to
force the logging format to be disabled. It also removes
`enable_logging` calls except for in MLC entrypoints (e.g. CLI main).

python/mlc_llm/bench/api_endpoint.py

@@ -12,7 +12,6 @@
 from mlc_llm.bench.request_record import Metrics, RequestRecord, ServerMetrics
 from mlc_llm.support import logging
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/bench/request_processor.py

@@ -19,7 +19,6 @@
 from mlc_llm.protocol.openai_api_protocol import ChatCompletionMessage, DebugConfig
 from mlc_llm.support import logging
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/bench/request_record.py

@@ -8,7 +8,6 @@
 from mlc_llm.protocol.openai_api_protocol import ChatCompletionRequest
 from mlc_llm.support import logging
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/cli/delivery.py

@@ -16,7 +16,6 @@
 from mlc_llm.support.argparse import ArgumentParser
 from mlc_llm.support.style import bold, green, red
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 GEN_CONFIG_OPTIONAL_ARGS = [

python/mlc_llm/cli/lib_delivery.py

@@ -16,7 +16,6 @@
 from mlc_llm.support.constants import MLC_TEMP_DIR
 from mlc_llm.support.style import bold, green, red
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/cli/model_metadata.py

@@ -13,7 +13,6 @@
 from mlc_llm.support.config import ConfigBase
 from mlc_llm.support.style import green, red
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/serve/engine.py

@@ -30,7 +30,6 @@
 
 from . import engine_base
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/serve/engine_base.py

@@ -28,7 +28,6 @@
 from mlc_llm.support.style import green
 from mlc_llm.tokenizers import TextStreamer, Tokenizer
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/serve/sync_engine.py

@@ -29,7 +29,6 @@
 from mlc_llm.support import logging
 from mlc_llm.tokenizers import TextStreamer, Tokenizer
 
-logging.enable_logging()
 logger = logging.getLogger(__name__)
 
 

python/mlc_llm/support/logging.py

@@ -4,10 +4,13 @@
 """
 
 import logging
+import os
 
 
 def enable_logging():
     """Enable MLC's default logging format"""
+    if os.getenv("MLC_UNSET_LOGGING"):
+        return
     logging.basicConfig(
         level=logging.INFO,
         style="{",