healthy

type AlwaysSuccessfulCmd ¶

type AlwaysSuccessfulCmd struct{}

A Checker that always returns success. Usually used in cases where a service can't actually be health checked for some reason.

func (a *AlwaysSuccessfulCmd) Run(args string) (int, error)

type Check ¶

type Check struct {
	// The ID of this check
	ID string

	// The most recent status of this check
	Status int

	// The number of runs it has been in failed state
	Count int

	// The maximum number before we declare that it failed
	MaxCount int

	// String describing the kind of check
	Type string

	// The arguments to pass to the Checker
	Args string

	// The Checker to run to validate this
	Command Checker

	// The last recorded error on this check
	LastError error
}

A Check defines some information about how to talk to the service to determine health. Each Check has a Command that is used to actually do the work. The command is invoked each interval and passed the arguments stored in the Check. The default Check type is an HttpGetCmd and the Args must be the URL to pass to the check.

func NewCheck(id string) *Check

func (check *Check) ServiceStatus() int

func (check *Check) UpdateStatus(status int, err error)

type Checker ¶

type Checker interface {
	Run(args string) (int, error)
}

type ExternalCmd ¶

type ExternalCmd struct{}

A Checker that works with Nagios checks or other simple external tools. It expects a 0 exit code from the command that was run. Anything else is considered to be SICKLY. The command is passed as the args to the Run method. The command will be executed without a shell wrapper to keep the call as lean as possible in the majority case. If you need a shell you must invoke it yourself.

func (e *ExternalCmd) Run(args string) (int, error)

type HttpGetCmd ¶

type HttpGetCmd struct{}

A Checker that makes an HTTP get call and expects to get a 200-299 back as success. Anything else is considered a failure. The URL to hit is passed as the args to the Run method.

func (h *HttpGetCmd) Run(args string) (int, error)

type Monitor ¶

type Monitor struct {
	Checks               map[string]*Check
	CheckInterval        time.Duration
	DefaultCheckHost     string
	DiscoveryFn          func() []service.Service
	DefaultCheckEndpoint string
	sync.RWMutex
}

The Monitor is responsible for managing and running Checks. It has a fixed check interval that is used for all checks. Access must be synchronized so direct access to struct members is possible but requires use of the RWMutex.

func NewMonitor(defaultCheckHost string, defaultCheckEndpoint string) *Monitor

func (m *Monitor) AddCheck(check *Check)

func (m *Monitor) CheckForService(svc *service.Service, disco discovery.Discoverer) *Check

func (m *Monitor) GetCommandNamed(name string) Checker

func (m *Monitor) MarkService(svc *service.Service)

func (m *Monitor) Run(looper director.Looper)

func (m *Monitor) Services() []service.Service

func (m *Monitor) Watch(disco discovery.Discoverer, looper director.Looper)