services

Documentation

Overview

Package services contain the key components of the Chainlink node. This includes the Application, JobRunner, LogListener, and Scheduler.

Application

The Application is the main component used for starting and stopping the Chainlink node.

JobRunner

The JobRunner keeps track of Runs within a Job and ensures that they're executed in order. Within each Run, the tasks are also executed from the JobRunner.

JobSubscriber

The JobSubscriber coordinates running job events with the EventLog in the Store, and also subscribes to the given address on the Ethereum blockchain.

Scheduler

The Scheduler ensures that recurring events are executed according to their schedule, and one-time events occur only when the specified time has passed.

Index

• type CheckFunc
• type Checkable
• type Checker
  • func NewChecker() Checker
• type Config
• type Meta
• type Nurse
  • func NewNurse(cfg Config, log logger.Logger) *Nurse
  • func (n *Nurse) AddCheck(reason string, checkFunc CheckFunc)
  • func (n *Nurse) Close() error
  • func (n *Nurse) GatherVitals(reason string, meta Meta)
  • func (n *Nurse) Start() error
• type Service
• type State
• type Status

Types

type CheckFunc

type CheckFunc func() (unwell bool, meta Meta)

type Checkable

type Checkable interface {
	// Checkables should return nil if ready, or an error message otherwise.
	Ready() error
	// Checkables should return nil if healthy, or an error message otherwise.
	Healthy() error
}

Checkable should be implemented by any type requiring health checks.

type Checker

type Checker interface {
	// Register a service for health checks.
	Register(name string, service Checkable) error
	// Unregister a service.
	Unregister(name string) error
	// IsReady returns the current readiness of the system.
	// A system is considered ready if all checks are passing (no errors)
	IsReady() (ready bool, errors map[string]error)
	// IsHealthy returns the current health of the system.
	// A system is considered healthy if all checks are passing (no errors)
	IsHealthy() (healthy bool, errors map[string]error)

	Start() error
	Close() error
}

Checker provides a service which can be probed for system health.

func NewChecker

func NewChecker() Checker

type Config

type Config interface {
	AutoPprofProfileRoot() string
	AutoPprofPollInterval() models.Duration
	AutoPprofGatherDuration() models.Duration
	AutoPprofGatherTraceDuration() models.Duration
	AutoPprofMaxProfileSize() utils.FileSize
	AutoPprofCPUProfileRate() int
	AutoPprofMemProfileRate() int
	AutoPprofBlockProfileRate() int
	AutoPprofMutexProfileFraction() int
	AutoPprofMemThreshold() utils.FileSize
	AutoPprofGoroutineThreshold() int
}

type Meta

type Meta map[string]interface{}

type Nurse

type Nurse struct {
	utils.StartStopOnce
	// contains filtered or unexported fields
}

func NewNurse

func NewNurse(cfg Config, log logger.Logger) *Nurse

func (*Nurse) AddCheck

func (n *Nurse) AddCheck(reason string, checkFunc CheckFunc)

func (*Nurse) Close

func (n *Nurse) Close() error

func (*Nurse) GatherVitals

func (n *Nurse) GatherVitals(reason string, meta Meta)

func (*Nurse) Start

func (n *Nurse) Start() error

type Service

type Service interface {
	// Start the service.
	Start() error
	// Close stops the Service.
	// Invariants: Usually after this call the Service cannot be started
	// again, you need to build a new Service to do so.
	Close() error

	Checkable
}

Service represents a long running service inside the Application.

Typically a Service will leverage utils.StartStopOnce to implement these calls in a safe manner.

Template

Mockable Foo service with a run loop

//go:generate mockery --name Foo --output ../internal/mocks/ --case=underscore
type (
	// Expose a public interface so we can mock the service.
	Foo interface {
		service.Service

		// ...
	}

	foo struct {
		// ...

		stop chan struct{}
		done chan struct{}

		utils.StartStopOnce
	}
)

var _ Foo = (*foo)(nil)

func NewFoo() Foo {
	f := &foo{
		// ...
	}

	return f
}

func (f *foo) Start() error {
	return f.StartOnce("Foo", func() error {
		go f.run()

		return nil
	})
}

func (f *foo) Close() error {
	return f.StopOnce("Foo", func() error {
		// trigger goroutine cleanup
		close(f.stop)
		// wait for cleanup to complete
		<-f.done
		return nil
	})
}

func (f *foo) run() {
	// signal cleanup completion
	defer close(f.done)

	for {
		select {
		// ...
		case <-f.stop:
			// stop the routine
			return
		}
	}

}

type State

type State struct {
	// contains filtered or unexported fields
}

type Status

type Status string

const (
	StatusPassing Status = "passing"
	StatusFailing Status = "failing"
)