How to Check Error Logs in CodeIgniter 4: Ultimate Tutorial

How to Check Error Logs in CodeIgniter 4

Error logging is a crucial aspect of web application development and maintenance. It helps developers track down issues and ensure their applications run smoothly. In this post, we’ll walk you through the steps to configure and check error logs in CodeIgniter 4.

Error logs provide valuable insights into the behavior of your application. They can reveal problems that might not be immediately apparent, such as deprecated functions, warnings, or even critical errors that could lead to application crashes. By diligently monitoring error logs, developers can proactively address potential issues before they escalate, ensuring a more stable and reliable application.

In this guide, we will explore how to check error logs in CodeIgniter 4.

1. Configuring Logging in CodeIgniter 4

Before you can check error logs, you need to ensure logging is properly configured in your CodeIgniter 4 application.

A. Log Configuration File

1) Locate the Logger Configuration:

Open the Logger.php file located in the app/Config directory of your CodeIgniter project.


2) Set the Threshold Level:

The threshold level determines the types of messages that will be logged. You can configure it by setting the $threshold property. The available levels are:

  • 0 = Disables logging
  • 1 = Error Messages (including PHP errors)
  • 2 = Debug Messages
  • 3 = Informational Messages
  • 4 = All Messages


3) Specify the Log Path:

The directory where log files will be stored is set using the $path property.

public $path = WRITEPATH . 'logs/'; // Default path

4) Set File Permissions:

Define the permissions for log files with the $filePermissions property.

public $filePermissions = 0644; // Default permissions

2) Viewing Log Files

Log files are stored in the directory specified in the Logger.php configuration. By default, this is the writable/logs directory.

1) Navigate to the Logs Directory:

Open the writable/logs directory in your CodeIgniter project.

2) Open a Log File:

Log files are typically named by the date they were created, such as log-2023-06-17.php. Open the file you want to review.

3) Interpret the Log Entries:

Each log entry includes a timestamp, the logging level, and the message.

3. Writing Custom Log Messages

You can also write custom log messages from your application code using the log_message function. This is useful for debugging and tracking application behavior.


log_message('error', 'This is an error message');
log_message('debug', 'This is a debug message');
log_message('info', 'This is an info message');

4. Example of a Log Entry

Here’s what a typical log entry might look like:
ERROR - 2023-06-17 12:34:56 --> Severity: Error --> Call to undefined function example_function() /path/to/file.php 123
DEBUG - 2023-06-17 12:35:00 --> Debugging message here
INFO - 2023-06-17 12:36:00 --> Informational message here

5. Additional Tips

  • Environment Configuration: Ensure your environment configuration is set correctly in the .env file. For example, CI_ENVIRONMENT = development enables detailed error messages and logging.

  • Customize Error Handling: You can customize error handling by modifying app/Config/Exceptions.php if needed.

  • To effectively manage and interpret error logs in your CodeIgniter 4 application, follow these steps to ensure smooth development and maintenance:

    1. Configuration: Begin by configuring error logging settings in the app/Config/Logger.php file. Adjust the threshold level to determine which types of errors are logged (e.g., debug, info, notice, warning, error). You can also configure the log path and file permissions here.

    2. Error Handling: CodeIgniter 4 provides a robust error handling system. Ensure that app/Config/Boot/development.php (or production.php for production) has appropriate error reporting levels set. For development, use error_reporting(E_ALL) to capture all errors, whereas for production, you might want to suppress notices and warnings by setting error_reporting(E_ERROR | E_PARSE).

    3. Accessing Logs: Error logs are stored in the writable/logs directory by default. Regularly check this directory to review logs and diagnose issues. Use a log viewer or a text editor to open and analyze these logs.

    4. Interpreting Logs: Each log entry includes a timestamp, log level, and a detailed message. Familiarize yourself with these components to quickly identify and address issues. Look for patterns or recurring errors to spot underlying problems.

    By following these steps, your CodeIgniter 4 application will be well-equipped to handle and log errors efficiently. This process aids in a smoother development and maintenance experience, ensuring that potential issues are promptly identified and resolved.


This version is designed to be clear, concise, and informative, making it suitable for a blog post. Feel free to adjust the tone and detail level according to your audience’s familiarity with CodeIgniter.

Understanding CodeIgniter 4 Logging Configuration
Understanding How to Check Error Logs in CodeIgniter 4 Ultimate Tutorial
How to Check Error Logs in CodeIgniter 4: Ultimate Tutorial

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