healthcheck-go-sdk

This is library for implementing k8s health check with go-restful

It provides dependencies health checking which returns dependency info, health status, timestamp and last error information of the dependency check result.

What's new in v2

Support soft and hard dependency option. AddHealthCheck defaults to soft and AddHardHealthCheck is available for registering a hard dependency. A soft dependency will not affect the overall healthy status of the service if the dependency is not healthy, meanwhile a hard dependency health will.
Support background periodic check instead of immediate check on every /healthz request
The /healthz response now returns last call time, last known good call time, and last error message of the corresponding dependency health check
New UpdateHealth method to enable the implementer service to update a dependency health
CheckFunc templates improvements

Usage

Installing

go get -u github.com/AccelByte/healthcheck-go-sdk/v2

NOTE: since the v2 includes eventstream-go-sdk v4 template check function, you will need to make sure that cgo is enabled (configurable with CGO_ENABLED=1 environment variable) and parsing -tags musl param when building your Go application in Alpine Linux.

Reference: https://github.com/AccelByte/eventstream-go-sdk#v4

Initiating

h := healthcheck.New(&healthcheck.Config{
ServiceName: "serviceName",
BasePath: "/servicePath"},
BackgroundCheckInterval: 60*time.Second,
})

Registering a (soft) dependency (recommended)

redisClient := new(redis.Client)
timeout := 5 * time.Second
h.AddHealthCheck("redis", "redis:6379", h.RedisHealthCheck(redisClient, timeout))

Registering a hard dependency

h.AddHardHealthCheck("other-dependency", "dependency:1234", func() error {
// do checking
return nil
})

Use periodic background checking (recommended)

h.StartBackgroundCheck(ctx)

Registering health check webservice to a go-restful container

serviceContainer := restful.NewContainer()
...
serviceContainer.Add(h.AddWebservice())

Methods for Updating Health Dependency

There are two ways for a dependency health to be updated.

The first one is by attaching a check function when adding a dependency using AddHealthCheck or AddHardHealthCheck as shown in the previous section. It suits well if the dependency already provides a way for doing health check, hence the check can be done easily inside the check function.

When a dependency does not provide a straight-forward way for health check and there is no easy workaround, we can use UpdateHealth instead to update the dependency health. The idea is to update the dependency health status right after the dependency is called.

h.AddHealthCheck("emailProvider", "https://email-provider", nil) // register dependency health check with nil check function

...

err := emailProvider.Send(from, to, emailBody)
if err != nil {
	_ = h.UpdateHealth("emailProvider", false, &healthcheck.CheckError{Timestamp: time.Now(), Message: err.Error()}) // update health to false with check error included
	return err
}

_ = h.UpdateHealth("emailProvider", true, nil) // update to healthy if succeed

Check Funtion Templates

Health check function templates are available at checks.go

AccelByte / healthcheck-go-sdk