Active health check

[iyangsj]

Background

• BFE can be configured with Passive Health Check (i.e. Outlier Detection) and use responses from real requests to determine whether an backend instance is healthy.

Description
Add Active Health Check support:

• Actively and periodically send health checking requests to backend.
• Use responses from health checking requests to determine whether an backend instance is healthy.

Changes to configuration

• Add configuration option CheckMode in BackendCheck Configuration

type BackendCheck struct {
	...
	CheckMode *string    // health check mode (PASSIVE/ACTIVE)
}

[nitishm]

@iyangsj I would love to take on this task. What would this entail?

[iyangsj]

@nitishm Thanks for your contribution! The issue has been updated.

[nitishm]

@iyangsj So I make the configuration change. Where does the configuration get used? I am searching for the existing passive health check code. Looking at healthcheck.go https://github.com/baidu/bfe/blob/develop/bfe_balance/backend/health_check.go but kind find the right place to plug it in.