Python logging - 1

Python's logging module is a powerful tool for tracking events in applications. It provides flexibility in handling log messages and directing them to different outputs, such as files, consoles, or external monitoring services. Here’s a structured way to explore Python logging:

1.Basics of Python Logging

Python’s built-in logging module allows you to log messages with different severity levels.

For example:

import logging

# Configure basic logging
logging.basicConfig(
    filename="app.log",  # Logs will be saved in 'app.log'
    filemode="w",        # Overwrites the file each run
    format="%(asctime)s - %(levelname)s - %(message)s",
    level=logging.DEBUG  # Set log level
)

# Generate log messages
logging.debug("This is a debug message")
logging.info("This is an info message")
logging.warning("This is a warning message")
logging.error("This is an error message")
logging.critical("This is a critical message")

print("Logging completed. Check 'app.log' for output.")

2️⃣ Run the Script

Open a terminal or command prompt and navigate to the folder where the file is saved.

Run the script with:

or, if using Python 3:

3️⃣ Check the Output

Console Output

Since we are only logging to a file (not the console), the terminal output will be:

File Output (app.log)

Open the app.log file in any text editor, and you’ll see:

2. Configuring Log Output

You can specify where logs should be written using basicConfig():

Then, when you run the script, the log messages will appear in the terminal:

5️⃣ Logging to Both Console and File

Modify your script to send logs to both console and file:

Output

📌 Terminal (console) will only show WARNING, ERROR, and CRITICAL messages:

📌 app.log file will contain all log messages:

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