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Logging Monitoring - Usage Examples

This document provides usage examples for the Logging Monitoring module.

Example 1: Basic Setup and Logging​

This example demonstrates how to initialize the logging system in a main application script and use a logger in another module.

1. Configure .env file (in project root):

# .env
CODOMYRMEX_LOG_LEVEL=DEBUG
CODOMYRMEX_LOG_FILE=app_debug.log
CODOMYRMEX_LOG_FORMAT="%(asctime)s - %(levelname)s - %(name)s - %(message)s"
CODOMYRMEX_LOG_OUTPUT_TYPE=TEXT

2. Main application script (e.g., main.py in project root):

from codomyrmex.logging_monitoring import setup_logging, get_logger
import my_module # Assuming my_module.py exists

def run_app():
    # Initialize logging ONCE at the start of your application
    setup_logging()

    # Get a logger for the main script itself (optional)
    logger = get_logger(__name__) # __name__ will be '__main__' here
    logger.info("Application starting...")
    logger.debug("This is a debug message from the main application.")

    # Call functions from other modules that use logging
    my_module.do_something()

    logger.info("Application finished.")

if __name__ == "__main__":
    run_app()

3. Another module (e.g., my_module.py):

from codomyrmex.logging_monitoring import get_logger

# Get a logger specific to this module
# Using __name__ (which will be 'my_module') is a best practice
logger = get_logger(__name__)

def do_something():
    logger.info("do_something() called in my_module.")
    # Simulate some work
    try:
        x = 1 / 0
    except ZeroDivisionError:
        logger.error("Attempted to divide by zero!", exc_info=True) # exc_info=True logs stack trace
    logger.debug("Finished attempt in do_something().")

Expected Outcome​

  • Console Output: You will see log messages (DEBUG level and above) printed to the console, formatted as specified in CODOMYRMEX_LOG_FORMAT.
  • File Output: A file named app_debug.log will be created (or appended to) in the same directory as main.py (or wherever the relative path resolves from the CWD). It will contain the same log messages.
  • Log messages from main.py will have __main__ as the logger name.
  • Log messages from my_module.py will have my_module as the logger name.

Example 2: Using Detailed Log Format and Different Log Level​

This example shows how to use the "DETAILED" log format and set a higher log level (e.g., WARNING) to reduce verbosity.

1. Configure .env file (in project root):

# .env
CODOMYRMEX_LOG_LEVEL=WARNING
CODOMYRMEX_LOG_FORMAT=DETAILED
CODOMYRMEX_LOG_OUTPUT_TYPE=TEXT

2. Using the same Python scripts as in Example 1.

Expected Outcome​

  • Console Output:
    • Only WARNING and ERROR level messages will be displayed.
    • The format will be more detailed: %(asctime)s - %(name)s - %(levelname)s - %(module)s:%(funcName)s:%(lineno)d - %(message)s.
    • You would not see the "Application starting..." (INFO) and debug messages because the level is WARNING.
    • You would see the "Attempted to divide by zero!" (ERROR) message from my_module.
  • File Output: No log file will be created as CODOMYRMEX_LOG_FILE is not set.

Example 3: JSON Log Output​

This example demonstrates how to configure the logging system to output logs in JSON format.

1. Configure .env file (in project root):

# .env
CODOMYRMEX_LOG_LEVEL=INFO
CODOMYRMEX_LOG_FILE=app_json.log
CODOMYRMEX_LOG_OUTPUT_TYPE=JSON
# CODOMYRMEX_LOG_FORMAT is ignored when CODOMYRMEX_LOG_OUTPUT_TYPE is JSON

2. Using the same Python scripts as in Example 1 (main.py and my_module.py).

Expected Outcome​

  • Console Output: Log messages (INFO level and above) will be printed to the console, formatted as JSON objects, one per line.
  • File Output: A file named app_json.log will be created (or appended to). It will contain the same JSON log messages.
  • Each JSON log entry will contain fields like timestamp, level, name, module, funcName, lineno, and message.
  • If extra data is passed to a log call (e.g., logger.info("message", extra={"custom_key": "custom_value"})), it will appear under an "extra" field in the JSON.

Example JSON Log Entry (content will vary):

{"timestamp":"2023-10-27T12:34:56.789012Z","level":"INFO","name":"my_module","module":"my_module","funcName":"do_something","lineno":10,"message":"do_something() called in my_module."}
{"timestamp":"2023-10-27T12:34:56.790000Z","level":"ERROR","name":"my_module","module":"my_module","funcName":"do_something","lineno":15,"message":"Attempted to divide by zero!","exception":"Traceback (most recent call last):\
  File \\"my_module.py\\\", line 13, in do_something\
    x = 1 / 0\
ZeroDivisionError: division by zero"}

Common Pitfalls & Troubleshooting​

  • Issue: No logs are appearing, or logs are not at the expected level.

    • Solution:
      1. Ensure setup_logging() is called once at the very beginning of your application.
      2. Verify the CODOMYRMEX_LOG_LEVEL in your .env file is set correctly (e.g., DEBUG, INFO).
      3. Check that the .env file is in the project root and is being loaded (e.g., no typos in environment variable names).
      4. Ensure python-dotenv is installed.

  • Issue: "No handlers could be found for logger X" message.

    • Solution: This usually means setup_logging() was not called before get_logger() was used, or the setup failed silently. Ensure setup_logging() is called first and check for any warning messages during its execution (e.g., problems opening a log file).

  • Issue: Log file is not being created or written to.

    • Solution:
      1. Check if CODOMYRMEX_LOG_FILE is correctly set in your .env file.
      2. Ensure the application has write permissions for the specified file path and that the directory path exists. The logger does not create directories.
      3. Look for any warning messages printed to the console by setup_logging() regarding file access issues.

  • Issue: Logs from third-party libraries are too verbose or are missing.

    • Solution:
      • The current setup_logging() configures the root logger. If third-party libraries use standard Python logging, their messages should be captured.
      • To silence a specific verbose library: logging.getLogger("some_verbose_library").setLevel(logging.WARNING) after your setup_logging() call.
      • To make a quiet library louder (if it logs to a specific logger and its level is higher than your root logger): logging.getLogger("some_quiet_library").setLevel(logging.DEBUG) after setup_logging(). You also need to ensure your root logger level (set by CODOMYRMEX_LOG_LEVEL) is also at least DEBUG.