health

Documentation

Overview

Package health defines standard interfaces and utilities for health checks.

Index

• Constants
• func NewClient(cc grpc.ClientConnInterface) grpc_health_v1.HealthClient
• type CheckFunc
  • func (c CheckFunc) CheckHealth(ctx context.Context) error
• type CheckRequest
• type CheckResponse
• type Checker
• type Config
• type MServer
  • func NewServer(m map[string]Checker, opts ...ServerOption) *MServer
  • func (s *MServer) Check(ctx context.Context, req *CheckRequest) (*CheckResponse, error)
  • func (s *MServer) Close() error
  • func (s *MServer) Init(status Status) error
  • func (s *MServer) Register(srv *grpc.Server)
  • func (s *MServer) ServeHTTP(w http.ResponseWriter, r *http.Request)
  • func (s *MServer) SetStatus(service string, status Status)
  • func (s *MServer) Watch(req *CheckRequest, srv WatchServer) error
• type Server
• type ServerOption
  • func FromConfig(conf Config) ServerOption
  • func FromEnv(opts ...config.ReadOption) ServerOption
  • func Interval(d time.Duration) ServerOption
  • func Logger(l log.Logger) ServerOption
  • func Timeout(d time.Duration) ServerOption
• type Status
• type StatusSetter
• type WatchServer

Constants

const (
	StatusUnknown        = grpc_health_v1.HealthCheckResponse_UNKNOWN
	StatusServing        = grpc_health_v1.HealthCheckResponse_SERVING
	StatusNotServing     = grpc_health_v1.HealthCheckResponse_NOT_SERVING
	StatusServiceUnknown = grpc_health_v1.HealthCheckResponse_SERVICE_UNKNOWN
)

Status const defines short name for grpc_health_v1.HealthCheckResponse_ServingStatus.

const (
	// OverallServiceName is service name of server's overall status.
	OverallServiceName = ""
)

Functions

func NewClient

func NewClient(cc grpc.ClientConnInterface) grpc_health_v1.HealthClient

NewClient return a new HealthClient.

Types

type CheckFunc

type CheckFunc func(context.Context) error

CheckFunc is quick way to define a health checker.

func (CheckFunc) CheckHealth

func (c CheckFunc) CheckHealth(ctx context.Context) error

CheckHealth implements Checker interface.

type CheckRequest

type CheckRequest = grpc_health_v1.HealthCheckRequest

CheckRequest is an alias of grpc_health_v1.HealthCheckRequest.

type CheckResponse

type CheckResponse = grpc_health_v1.HealthCheckResponse

CheckResponse is an alias of grpc_health_v1.HealthCheckResponse

type Checker

type Checker interface {
	// CheckHealth establish health check to the target service.
	// Return error if target service cannot be reached
	// or not working properly.
	CheckHealth(ctx context.Context) error
}

Checker provide functionality for checking health of a service.

type Config

type Config struct {
	Interval time.Duration `envconfig:"HEALTH_CHECK_INTERVAL" default:"60s"`
	Timeout  time.Duration `envconfig:"HEALTH_CHECK_TIMEOUT" default:"1s"`
}

Config hold server config.

type MServer

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

MServer is a simple implementation of Server.

func NewServer

func NewServer(m map[string]Checker, opts ...ServerOption) *MServer

NewServer return new gRPC health server.

func (*MServer) Check

func (s *MServer) Check(ctx context.Context, req *CheckRequest) (*CheckResponse, error)

Check implements health.Server.

func (*MServer) Close

func (s *MServer) Close() error

Close implements health.Server.

func (*MServer) Init

func (s *MServer) Init(status Status) error

Init implements health.Server.

func (*MServer) Register

func (s *MServer) Register(srv *grpc.Server)

Register implements health.Server.

func (*MServer) ServeHTTP

func (s *MServer) ServeHTTP(w http.ResponseWriter, r *http.Request)

ServeHTTP implements health.Server.

func (*MServer) SetStatus

func (s *MServer) SetStatus(service string, status Status)

SetStatus implements health.Server

func (*MServer) Watch

func (s *MServer) Watch(req *CheckRequest, srv WatchServer) error

Watch implements health.Server.

type Server

type Server interface {
	// Implements grpc_health_v1.HealthServer for general health check and
	// load balancing according to gRPC protocol.
	grpc_health_v1.HealthServer
	// Implements http.Handler Check API via HTTP.
	http.Handler
	// Register register the Server with grpc.Server
	Register(srv *grpc.Server)
	// Init initialize status, perform necessary setup and start a
	// first health check immediately to update overall status and all
	// dependent services's status.
	Init(status Status) error
	// Close close the underlying resources.
	// It sets all serving status to NOT_SERVING, and configures the server to
	// ignore all future status changes.
	Close() error
}

Server provides health check services via both gRPC and HTTP. The implementation must follow protocol defined in https://github.com/grpc/grpc/blob/master/doc/health-checking.md

type ServerOption

type ServerOption func(srv *MServer)

ServerOption is a function to provide additional options for server.

func FromConfig

func FromConfig(conf Config) ServerOption

FromConfig is an option to override server's config.

func FromEnv

func FromEnv(opts ...config.ReadOption) ServerOption

FromEnv is an option to load config from environment variables.

func Interval

func Interval(d time.Duration) ServerOption

Interval is an option to set interval for health check.

func Logger

func Logger(l log.Logger) ServerOption

Logger is an option to set logger for the health check server.

func Timeout

func Timeout(d time.Duration) ServerOption

Timeout is an option to set timeout for each service health check.

type Status

type Status = grpc_health_v1.HealthCheckResponse_ServingStatus

Status is an alias of grpc_health_v1.HealthCheckResponse_ServingStatus.

type StatusSetter

type StatusSetter interface {
	// SetStatus is called when need to reset the serving status of a service
	// or insert a new service entry into the statusMap.
	// Use empty string for setting overall status.
	SetStatus(name string, status Status)
}

StatusSetter is an interface to set status for a service according to gRPC Health Check protocol.

type WatchServer

type WatchServer = grpc_health_v1.Health_WatchServer

WatchServer is an alias of grpc_health_v1.Health_WatchServer.