Only process some metrics when OpenTSDB is enabled

[harudark]

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Description

When OpenTSDB is not enabled, the processing of metrics sending to OpenTSDB is in vain.

The underlying reason to make this change is to make the scheduler run more accurately.

In production, it takes about 100 - 300ms to process these metrics. Suppose the time to process metric is always 200ms and one alert is scheduled to run every minute, the actual number of alert execution for one day becomes 60 60 24 / 60.2 = 1435.2, less than expected 1440. Whether the reduced 5 times execution matters or not depends on use cases and people may have different opinions.

The real problem we have is one important minutely SLO metric bosun_uptime relying on the accuracy of the scheduler. In current situation, because of this extra processing time, every few minutes, the minutely alert starting time is delayed 1s, which causes the metric missing problem.

Ideally, we may introduce jitter to reduce the impact of metrics processing time or optimze the processing time, but both are tricky to implement. This change is not very elegant but straightforward.

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How has this been tested?

Test in production

Checklist:

• [x] This contribution follows the project's code of conduct
• [x] This contribution follows the project's contributing guidelines
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.