forked from rcrowley/go-metrics
/
healthcheck.go
80 lines (66 loc) · 2.07 KB
/
healthcheck.go
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package metrics
// Healthchecks hold an error value describing an arbitrary up/down status.
type Healthcheck interface {
Check()
Error() error
Healthy()
Unhealthy(error)
}
// GetOrRegisterHealthcheck returns an existing Healthcheck or
// constructs and registers a new StandardHealthcheck.
func GetOrRegisterHealthcheck(name string, r Registry, f func(Healthcheck)) Healthcheck {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, func() Healthcheck { return NewHealthcheck(f) }).(Healthcheck)
}
// NewHealthcheck constructs a new Healthcheck which will use the given
// function to update its status.
func NewHealthcheck(f func(Healthcheck)) Healthcheck {
if UseNilMetrics {
return NilHealthcheck{}
}
return &StandardHealthcheck{nil, f}
}
// NewRegisteredHealthcheck constructs and registers a new StandardHealthcheck.
func NewRegisteredHealthcheck(name string, r Registry, f func(Healthcheck)) Healthcheck {
c := NewHealthcheck(f)
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// NilHealthcheck is a no-op.
type NilHealthcheck struct{}
// Check is a no-op.
func (NilHealthcheck) Check() {}
// Error is a no-op.
func (NilHealthcheck) Error() error { return nil }
// Healthy is a no-op.
func (NilHealthcheck) Healthy() {}
// Unhealthy is a no-op.
func (NilHealthcheck) Unhealthy(error) {}
// StandardHealthcheck is the standard implementation of a Healthcheck and
// stores the status and a function to call to update the status.
type StandardHealthcheck struct {
err error
f func(Healthcheck)
}
// Check runs the healthcheck function to update the healthcheck's status.
func (h *StandardHealthcheck) Check() {
h.f(h)
}
// Error returns the healthcheck's status, which will be nil if it is healthy.
func (h *StandardHealthcheck) Error() error {
return h.err
}
// Healthy marks the healthcheck as healthy.
func (h *StandardHealthcheck) Healthy() {
h.err = nil
}
// Unhealthy marks the healthcheck as unhealthy. The error is stored and
// may be retrieved by the Error method.
func (h *StandardHealthcheck) Unhealthy(err error) {
h.err = err
}