12 Logging Best Practices: Do's & Don'ts

Here's a quick guide to effective logging in software development:

1. Define clear logging objectives
2. Use appropriate log levels
3. Implement structured logging
4. Write meaningful log messages
5. Centralize log management
6. Implement log rotation and retention policies
7. Don't log sensitive information
8. Don't ignore performance impact
9. Don't rely solely on logs for monitoring
10. Don't neglect log security
11. Don't log everything
12. Don't forget to review and maintain logs

These practices help create a robust logging system that aids in debugging, improves system performance, and maintains data security.

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1. Do Define Clear Logging Objectives

Objective Alignment

Setting clear logging goals helps focus your efforts and makes sure you're tracking the right things. Without clear goals, you might log too much or too little, wasting time and missing key information.

Log Level Usage

When setting logging goals, think about which log levels to use. Log levels help sort messages by how important they are. Common levels are:

Choose the levels that fit your needs and help you track what matters most.

Structured Format

Use a set format for your log messages. This makes them easier to read and analyze. Include things like:

• Time the event happened
• Log level
• Message
• Any other useful details

A good format helps you find and use the information you need quickly.

Why Clear Logging Goals Matter

Clear logging goals help you:

• Focus on what's important
• Avoid logging too much or too little
• Find and fix problems faster
• Match your logging to your system's needs

How to Set Clear Logging Goals

1. Decide what you want to track and why 2. Pick which log levels you'll use 3. Choose a format for your log messages 4. Make sure your goals fit with what your system needs to do 5. Check and update your goals regularly to keep them useful

2. Do Use Appropriate Log Levels

Log Level Usage

Picking the right log level helps sort log entries by how important they are. This makes it easier to find and fix problems. Here are the common log levels:

Using the right level helps you log the right amount of info and spot big problems quickly.

Contextual Information

Think about where you'll use the log when picking a level. For example:

Best Practices for Log Levels

Here's how to use log levels well:

• Use Fatal for big problems that stop everything
• Use Error for issues that break things
• Use Warn for possible future problems
• Use Info for general system updates
• Use Debug for extra details when fixing issues
• Use Trace for very detailed info when hunting bugs
• Don't use too many levels - it makes sorting hard
• Use the same levels throughout your app for clarity

3. Do Implement Structured Logging

Structured Format

Structured logging organizes log data in a set format. It uses key-value pairs instead of plain text. This makes logs easier to read and analyze.

Benefits of Structured Logging

Best Practices for Structured Logging

To use structured logging well:

1. Pick one format: Use the same format, like JSON, for all logs

2. Add helpful details: Include things like time, error codes, and other useful info

3. Use standard labels: Make labels and time formats the same across all logs

4. Keep it simple: Don't use too many fields in your logs

5. Use a log tool: Pick a tool that can handle and analyze your structured logs

Structured vs. Unstructured Logging

4. Do Write Meaningful Log Messages

Contextual Information

Good log messages should include key details that help explain what happened. This makes it easier to understand and fix problems. Include things like:

• Error codes
• Important data related to the event
• Time it happened
• User or system IDs
• What the system was doing

Adding this info helps teams quickly find and fix issues.

Matching Goals

Write log messages that help with:

• Keeping track of what the system does
• Finding and fixing problems
• Meeting security and rule requirements
• Making the system work better

Keep these goals in mind when writing log messages.

Using Log Levels

Write messages that fit the right log level:

Using the right level helps get the right info to the right people.

Organized Format

Use a set format for log messages. This makes them easier to read and use. For example:

2022-07-27 14:30:00 ERROR [USER-123] User login failed: wrong password

This format shows:

• When it happened
• How serious it is
• Who it affects
• What went wrong

5. Do Centralize Log Management

Centralized log management helps collect and store logs from different sources in one place. This makes it easier to find and fix problems across your whole system.

Why Use Centralized Log Management?

How to Choose a Log Management Tool

When picking a tool to manage your logs, think about:

• Can it handle lots of logs?
• Is it safe?
• Is it easy to use?
• Does it work with your other tools?
• How much does it cost?

Some popular tools are ELK Stack, Splunk, and Sumo Logic.

Steps to Set Up Centralized Log Management

1. Pick a tool that fits your needs

2. Set up log collection from all your sources

3. Store logs in a central place

4. Set up ways to search and analyze your logs

5. Create alerts for important events

6. Train your team to use the new system

6. Do Implement Log Rotation and Retention Policies

Rotation and Retention

Log rotation and retention policies help manage logs better. Here's what they do:

• Log rotation: Renames, compresses, or deletes old log files when they get too big or old.
• Log retention: Sets how long to keep logs before deleting or storing them elsewhere.

These policies help save space, keep systems running well, and follow rules about data storage.

Benefits of Log Rotation and Retention

How to Do Log Rotation and Retention Well

1. Make Clear Rules: Decide how often to rotate logs and how long to keep them.
2. Use Tools: Set up software to rotate logs automatically.
3. Keep Logs Safe: Store logs where only the right people can see them.
4. Check Your System: Make sure your log rotation and retention are working right.

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7. Don't Log Sensitive Information

Sensitive Data Handling

When logging, avoid recording sensitive information like personal details, financial data, and health records. Logging this type of data can cause security problems and break rules.

Why It's Bad to Log Sensitive Information

Logging sensitive information can lead to:

How to Handle Sensitive Information Safely

To keep sensitive information out of logs:

• Hide sensitive data (e.g., credit card numbers, passwords)
• Use safe logging methods (e.g., encryption, access controls)
• Only let certain people see sensitive information
• Check logs often to make sure sensitive data isn't there

Following these steps helps keep sensitive information safe and follows the rules.

Good Things About Not Logging Sensitive Information

Not logging sensitive information helps:

• Keep data safer
• Follow the rules
• Lower the chance of problems

Tools for Safe Logging

Use these to log safely:

These tools help you log safely and protect sensitive information.

Wrap-up

Logging sensitive information can cause big problems. By hiding sensitive data, using safe logging methods, and limiting access, you can keep information safe and follow the rules. Not logging sensitive information helps keep data safe, follow rules, and avoid problems. Using the right tools helps you log safely and protect sensitive information.

8. Don't Ignore Performance Impact

Performance Impact

Logging can slow down your app if not done right. Poor logging can make your app run slowly, make it hard to fix problems, cost more, and create security risks.

Why Performance Impact Matters

Bad logging can hurt your app:

How to Log Without Slowing Things Down

To log well and keep your app fast:

• Use fast logging tools like Chronicle Logger and Log4j2 Memory Mapped File Appender
• Check how logging affects speed, especially for debug or info logs
• Use lazy logging to avoid extra work
• Try async logging when you can
• Don't log info that's hard to process
• Use JSON directly to save time later

These tips help you log without making your app slow.

Tools to Help Log Faster

Some tools can make logging faster:

These tools can help you log without slowing down your app.

Good Things About Fast Logging

Logging without slowing things down helps:

• Keep your app fast
• Make users happy
• Save money
• Keep things safe

When you log the right way, your app works better and costs less to run.

Wrap-up

Don't forget about how logging can slow things down. Use the right tools and methods to log without hurting your app's speed. This keeps your app running well and your users happy.

9. Don't Rely Solely on Logs for Monitoring

Monitoring Integration

Logging and monitoring are different but work together. Logging keeps track of what happens in your system. Monitoring looks at this information to spot problems.

Using only logs for monitoring can cause issues:

• Logs can be long and hard to read
• It's tough for people to check logs all the time
• Big systems make too many logs to read

Monitoring tools help by:

• Looking at log data quickly
• Finding problems faster
• Showing how the system is doing

Logs vs Monitoring

Why Use Both Logs and Monitoring

Using both logs and monitoring helps you:

• Understand your system better
• Find problems before they get big
• Make your system work better

How to Use Logs and Monitoring Together

To use logs and monitoring well:

1. Use tools that can read and understand logs
2. Keep all your logs in one place
3. Use a simple format for logs (like JSON)
4. Set up alerts for important issues
5. Look at your logs often to see patterns

10. Don't Neglect Log Security

Security Measures

Not protecting your logs can lead to data leaks and rule-breaking. It's important to keep your logs safe.

Protecting Log Data

To keep log data safe:

• Use encryption for logs when they're moving and stored
• Control who can see and change logs
• Use safe ways to send logs, like TLS or SSL
• Check who's looking at logs often to spot problems

Log Storage Security

When storing logs:

• Use a safe place to keep them, like a log management tool or secure cloud storage
• Encrypt stored logs and control who can access them
• Make backups of logs to avoid losing data if something goes wrong

Following Rules

Depending on what you do and where you are, you might need to follow certain rules about log security. Here are some examples:

Make sure you know which rules apply to you and follow them when keeping your logs safe.

Wrap-up

Not keeping logs safe can cause big problems like data leaks and breaking rules. By using things like encryption, controlling who can see logs, and storing them safely, you can protect your logs and follow the rules. Check who's looking at your logs often to make sure they're still safe.

11. Don't Log Everything

Log Selectivity

Logging too much can make it hard to find important issues. It's best to log only what you need. This doesn't mean logging nothing, but choosing what's useful.

Objective Alignment

Before logging, know what you want to achieve. Are you trying to:

• Fix bugs?
• Check how well things work?
• See what users do?

Once you know your goals, you can decide what to log.

Log Level Usage

Use log levels to sort your logs by how important they are. This helps you focus on big problems. Here's a simple guide:

Structured Format

Use a set format for your logs. This makes them easier to read and use. You can:

• Use JSON or XML
• Use a tool that helps organize logs

A set format helps you find important info quickly.

Contextual Information

Add details to your logs to help understand what happened. Include things like:

• Who did it (user ID)
• When it happened
• Where it came from (IP address)
• What device or browser was used

This extra info helps figure out why things happened.

Centralization

Keep all your logs in one place. This makes them easier to manage. You can:

• Use a tool to manage logs
• Store logs in the cloud

Keeping logs together helps you:

• Collect logs from different places
• Store them all in one spot
• Look at log data easily
• Set up alerts for problems

Rotation and Retention

Manage your logs well by:

• Changing log files regularly (like daily or weekly)
• Keeping logs for a set time (like 30 days or 1 year)
• Making logs smaller to save space

This helps you keep your logs organized and easy to use.

Sensitive Data Handling

Be careful with private info in logs:

• Hide sensitive details (like passwords)
• Use safe ways to send logs
• Store logs in a safe place

This keeps your logs safe and follows the rules.

Performance Impact

Think about how logging affects how fast your system works. Logging too much can slow things down. By choosing what to log carefully, you can keep your system running smoothly.

Monitoring Integration

Use your logs with your monitoring tools. This can help you:

• Set up alerts for problems
• See how your system is doing
• Make better decisions about your system

Security Measures

Keep your logs safe:

• Use safe ways to send logs
• Store logs in a secure place
• Control who can see the logs

This keeps your logs safe and follows the rules.

Regular Review

Check your logs often:

• Look at log data regularly
• Make sure log data matches other info
• Update how you log if needed

Checking your logs helps make sure they're correct and useful.

12. Don't Forget to Review and Maintain Logs

Regular Review

Checking logs often helps make sure they work well. When you look at logs regularly, you can:

• Find and fix problems early
• Make your system run better
• Keep things safe by spotting possible threats
• Improve how you handle logs

Log Analysis and Monitoring

Looking closely at logs and watching them is important. When you do this, you can:

• See patterns in how your system works
• Find odd things that might be unsafe
• Make your system work better
• Fix problems more easily

Log Maintenance

Taking care of logs is key. This means:

• Changing old logs and keeping them for the right time
• Updating how you handle logs when needed
• Making sure log info is correct and complete
• Backing up logs often

How to Review and Maintain Logs Well

To check and take care of logs the right way:

Conclusion

Good logging helps make software work better, find problems faster, and keep systems safe. By following the 12 logging tips in this article, developers can make their logging strong and useful.

Using these tips helps solve common logging problems, like:

• Handling lots of logs
• Keeping logs safe
• Dealing with different log types

This makes it easier to:

• Find and fix issues
• See what users are doing
• Make the system run better

Logging is a key part of making software. It's important to do it right. These tips help make logging work well, run smoothly, and stay safe. Remember, logging isn't just about writing messages. It's about building a system that helps you:

• Find problems
• Make things run faster
• Keep data safe

FAQs

What should logging practices do?

Good logging practices should:

• Set clear goals for logging
• Help with fixing problems
• Keep track of system health
• Follow rules and keep data safe

How to log the right way?

To log well:

How to log without slowing things down?

To log without hurting speed:

• Pick some logs to record, not all
• Use one log line for each request
• Set rules for how long to keep logs
• Put all logs in one place
• Use tools that can handle lots of logs quickly

These steps help you get useful info from logs without making your system slow.

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