Add configurable logging

Author: olliesilvester

pyproject.toml

@@ -41,6 +41,7 @@ dev = [
     "cachetools",
     "fastapi",
     "uvicorn",
+    "graypy"
 ]
 
 [project.scripts]

src/daq_config_server/log.py

@@ -1,24 +1,72 @@
 import logging
+from typing import Literal, TextIO
 
+from graypy import GELFTCPHandler
+from pydantic import BaseModel, HttpUrl
 
-# See https://github.com/DiamondLightSource/daq-config-server/issues/73
-# for making the logging configurable
-def get_default_logger(name: str = __name__) -> logging.Logger:
-    logger = logging.getLogger(name)
-    logger.setLevel(logging.INFO)
+LogLevel = Literal["NOTSET", "DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"]
 
-    # Prevent adding handlers multiple times
-    if not logger.handlers:
-        console_handler = logging.StreamHandler()
-        formatter = logging.Formatter(
-            "%(asctime)s - %(levelname)s - %(message)s", datefmt="%Y-%m-%d %H:%M:%S"
-        )
-        console_handler.setFormatter(formatter)
-        logger.addHandler(console_handler)
 
-    return logger
+class GraylogConfig(BaseModel):
+    enabled: bool = False
+    url: HttpUrl = HttpUrl("http://localhost:5555")
 
 
-# For now use a basic console-writing logger. Integrate properly with kubernetes in the
-# future
-LOGGER = get_default_logger("daq-config-server")
+class LoggingConfig(BaseModel):
+    level: LogLevel = "INFO"
+    graylog: GraylogConfig = GraylogConfig()
+
+
+def set_up_stream_handler(
+    logger: logging.Logger, logging_config: LoggingConfig
+) -> logging.StreamHandler[TextIO]:
+    """Creates and configures StreamHandler, then attaches to logger.
+
+    Args:
+        logger: Logger to attach handler to
+        logging_config: LoggingConfig
+    """
+    stream_handler = logging.StreamHandler()
+    stream_handler.setLevel(logging_config.level)
+
+    logger.addHandler(stream_handler)
+    return stream_handler
+
+
+def set_up_graylog_handler(
+    logger: logging.Logger, logging_config: LoggingConfig
+) -> GELFTCPHandler:
+    """Creates and configures GELFTCPHandler, then attaches to logger.
+
+    Args:
+        logger: Logger to attach handler to
+        logging_config: LoggingConfig
+    """
+    assert logging_config.graylog.url.host is not None, "Graylog URL missing host"
+    assert logging_config.graylog.url.port is not None, "Graylog URL missing port"
+    graylog_handler = GELFTCPHandler(
+        logging_config.graylog.url.host,
+        logging_config.graylog.url.port,
+    )
+    graylog_handler.setLevel(logging_config.level)
+
+    logger.addHandler(graylog_handler)
+    return graylog_handler
+
+
+def set_up_logging(logging_config: LoggingConfig) -> None:
+    """Configure root level logger for the config-server.
+
+    Configures root logger. Any other logger will propogate to this logger assuming the
+    default `logger.propagate` is True.
+
+    Args:
+        logging_config: LoggingConfig
+    """
+
+    logger = logging.getLogger()
+
+    logger.setLevel(logging_config.level)
+
+    if logging_config.graylog.enabled:
+        set_up_graylog_handler(logger, logging_config)

src/daq_config_server/whitelist.py

@@ -1,4 +1,5 @@
 import atexit
+import logging
 import time
 from functools import cache
 from pathlib import Path
@@ -11,7 +12,8 @@
     WHITELIST_REFRESH_RATE_S,
     WHITELIST_URL,
 )
-from daq_config_server.log import LOGGER
+
+LOGGER = logging.getLogger(__name__)
 
 
 class WhitelistFetcher: