mo-service: add periodic memory metrics logs

[reusee]

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #15973

What this PR does / why we need it:

log gc and memory metrics periodically

[matrix-meow]

@reusee Thanks for your contributions!

Pull Request Review:

Title:

The title of the pull request is clear and concise, indicating the addition of periodic memory metrics logs to the mo-service.

Body:

The body of the pull request provides relevant information about the type of PR, the issue it fixes, and the purpose of the changes. It mentions that the PR is an improvement and addresses issue #15973 by adding periodic memory metrics logs.

Changes:

1. Addition of Code for Periodic Memory Metrics:
   • The PR introduces a new function init() that sets up a goroutine to periodically log memory metrics.
   • It collects metrics related to garbage collection and memory usage and logs them periodically.
   • It uses the metrics package to gather metrics and zap for logging.
   • The formatMetricsValue function formats the metrics values based on their kind.
   • A sync.Pool is used to manage a pool of strings.Builder for efficient memory usage.

Suggestions for Improvement:

1. Avoid Hardcoding Time Interval:

   • Instead of using a fixed time interval of one second (time.NewTicker(time.Second)), consider making the interval configurable through a configuration parameter. This would allow users to adjust the frequency of logging based on their needs.

2. Error Handling:

   • Add error handling mechanisms in the goroutine to handle any potential errors that may occur during metric collection or logging. This will make the code more robust and prevent unexpected failures.

3. Resource Management:

   • Ensure proper resource management, especially with the use of sync.Pool. Make sure that resources are released appropriately to prevent memory leaks.

4. Logging Level:

   • Consider making the logging level configurable to allow users to control the verbosity of the memory metrics logs. This can be useful for debugging or production scenarios where different levels of detail are required.

5. Code Comments:

   • Add comments to explain the purpose of the functions, variables, and logic to improve code readability and maintainability.

6. Unit Testing:

   • Write unit tests to cover the new functionality added in this PR. This will ensure that the code behaves as expected and help prevent regressions in the future.

7. Security Considerations:

   • Ensure that sensitive information or data is not inadvertently logged in the memory metrics. Review the metrics being collected to avoid exposing any confidential information.

8. Optimization:

   • Consider optimizing the code for performance, especially in the metric collection and logging process, to minimize overhead and improve efficiency.

By addressing these suggestions, the code quality, maintainability, and security of the mo-service can be enhanced.