Saving PHP errors in a file

In a production environment it is a bad idea to display errors, since errors may display too much of internal technical information. However certain errors will be produced in production environment only. Developers and quality assurance people simply were not able to reproduce error conditions. In such a case it is possible to save errors in a log file. This is done via error_log command. This command has several options of how to deal with error messages. Please refer to the PHP documentation of how this command needs to be used. Please ensure file permissions that it is available to write to this file.

If there is more than a single server that saves errors in a log file, please consider aggregation of errors to a single location, it would be a pain in a neck to chase errors from server to server.

Why this can be done this way? Because in production environment developers may not have access to ini file, however they still may need a way to troubleshoot issues.

Logging Production Errors Study Guide

Quiz

Why is it generally a bad idea to display errors directly in a production environment?

What is a primary reason developers or QA might not be able to reproduce errors encountered in production?

What command is specifically mentioned for saving errors in a log file?

What crucial file permission needs to be checked when using error_log to write to a file?

What problem can arise if errors are logged across multiple servers?

What solution is suggested for the problem of errors being logged across multiple servers?

According to the text, why might developers need a way to troubleshoot production issues without access to the ini file?

Where should you refer for detailed information on how to use the error_log command?

What kind of information might be inadvertently displayed if errors are shown directly in production?

What are the two main groups of people mentioned who were unable to reproduce production errors?

Answer Key

It's a bad idea because errors can reveal too much internal technical information, which is a security risk.

Certain error conditions may only occur specifically in the production environment itself.

The error_log command is mentioned for saving errors in a log file.

You need to ensure that the file specified for logging has write permissions for the web server process.

Chasing errors from server to server becomes a difficult and time-consuming process ("a pain in a neck").

Aggregation of errors to a single location is suggested to avoid having to check multiple servers.

They may need to troubleshoot issues even without ini file access because they may not have access to modify it in the production environment.

You should refer to the PHP documentation for detailed usage of the error_log command.

Internal technical information could be inadvertently displayed to the user if errors are shown directly.

Developers and quality assurance people were the two groups mentioned as being unable to reproduce production errors.

Essay Questions

Discuss the security implications of displaying detailed error messages in a production environment and explain how logging helps mitigate these risks.

Analyze the logistical challenges presented by distributed systems (multiple servers) when it comes to error tracking and explain how error aggregation addresses these challenges.

Explain the specific scenario described where error_log is particularly useful for developers who may not have full access to modify server configurations.

Compare and contrast the typical error handling practices in development/testing environments versus a production environment based on the provided text.

Research and describe additional best practices for logging errors in a production environment beyond what is mentioned in the excerpt, including considerations like log rotation, log levels, and structured logging.

Glossary

Production Environment: The live environment where a software application is used by end-users.

Errors: Problems or issues that occur during the execution of a software application.

Logging: The process of recording events, including errors, in a file for later analysis.

Log File: A file where system and application events, such as errors, are recorded.

error_log command: A command used to send error messages to a log file or other destinations.

File Permissions: Settings that control who can access and modify a file.

Aggregation: The process of gathering data from multiple sources into a single location.

ini file: A configuration file used by PHP and other applications to store settings.

Troubleshoot: To identify and resolve problems or issues.

Production Error Logging Best Practices

Why is displaying errors in a production environment a bad idea?

Displaying errors directly in a production environment is discouraged because it can expose sensitive internal technical information to end-users, which could be a security risk or simply confuse them.

When is logging errors in a production environment particularly useful?

Logging errors is particularly useful for errors that occur only in the production environment and cannot be reproduced during development or quality assurance testing. This allows developers to troubleshoot issues that are unique to the production setup.

What is the primary command mentioned for logging errors?

The primary command mentioned for logging errors is error_log.

Where should I look for detailed information on using the error_log command?

For detailed information on how to use the error_log command and its various options, you should refer to the official PHP documentation.

What is a crucial consideration regarding file permissions when logging errors to a file?

When logging errors to a file, it is crucial to ensure that the file has the necessary write permissions so that the logging mechanism can successfully write error messages to it.

What is the recommendation when multiple servers are logging errors to files?

When errors are being logged to files on multiple servers, it is strongly recommended to aggregate these errors into a single location. This simplifies the process of troubleshooting as you don't have to check logs on each individual server.

Why is error logging in production important, even if developers don't have access to the ini file?

Error logging in production is important because it provides a way for developers to troubleshoot issues that only occur in the production environment, even if they lack direct access to modify the ini configuration file.

What are the main benefits of aggregating errors from multiple servers?

Aggregating errors from multiple servers into a single location significantly reduces the effort and time required to track and diagnose issues, making the troubleshooting process much more efficient.