healthz

Documentation

Index

• Variables
• type Endpoint
• type Logger
• type Resolver
  • func NewResolver(options ...ResolverOption) (*Resolver, error)
  • func (r *Resolver) Close()
  • func (r *Resolver) Next() ([]*naming.Update, error)
  • func (r *Resolver) Resolve(target string) (naming.Watcher, error)
• type ResolverOption
  • func SetCheckTimeout(timeout time.Duration) ResolverOption
  • func SetEndpoints(endpoints ...Endpoint) ResolverOption
  • func SetLogger(logger Logger) ResolverOption
  • func SetUpdateInterval(interval time.Duration) ResolverOption

Variables

var (

	// ErrNoEndpoints is returned when you passed no endpoints to the Resolver.
	ErrNoEndpoints = errors.New("no endpoints specified")
)

Types

type Endpoint

type Endpoint struct {
	Addr     string // e.g. 127.0.0.1:10000
	CheckURL string // e.g. http://127.0.0.1:10000/healthz
	// contains filtered or unexported fields
}

Endpoint is an endpoint that serves gRPC and responds to health checks on the CheckURL.

type Logger

type Logger interface {
	Printf(format string, values ...interface{})
}

Logger allows to pass an optional logger to the resolver.

type Resolver

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

Resolver implements the gRPC Resolver interface using a simple health endpoint check on a list of clients initially passed to the resolver.

See the gRPC load balancing documentation for details about Balancer and Resolver: https://github.com/grpc/grpc/blob/master/doc/load-balancing.md.

func NewResolver

func NewResolver(options ...ResolverOption) (*Resolver, error)

NewResolver initializes and returns a new Resolver.

It resolves addresses for gRPC connections to the given list of host:port endpoints. It runs HTTP-based health checks periodically to ensure that all endpoints are still reachable and healthy. If an endpoint does not respond in time, it is removed from the list of valid endpoints. Once it comes up again, it will be added to the list of healthy endpoints again, and traffic will be served to that endpoint again.

func (*Resolver) Close

func (r *Resolver) Close()

Close closes the watcher.

func (*Resolver) Next

func (r *Resolver) Next() ([]*naming.Update, error)

Next blocks until an update or error happens. It may return one or more updates. The first call will return the full set of instances available as NewResolver will look those up. Subsequent calls to Next() will block until the resolver finds any new or removed instance.

An error is returned if and only if the watcher cannot recover.

func (*Resolver) Resolve

func (r *Resolver) Resolve(target string) (naming.Watcher, error)

Resolve creates a watcher for target. The watcher interface is implemented by Resolver as well, see Next and Close.

type ResolverOption

type ResolverOption func(*Resolver) error

ResolverOption is a callback for setting the options of the Resolver.

func SetCheckTimeout

func SetCheckTimeout(timeout time.Duration) ResolverOption

SetCheckTimeout specifies the duration after which an endpoint is considered gone in a health check.

func SetEndpoints

func SetEndpoints(endpoints ...Endpoint) ResolverOption

SetEndpoints specifies the endpoints for the resolver.

func SetLogger

func SetLogger(logger Logger) ResolverOption

SetLogger allows to pass a logger for Resolver.

func SetUpdateInterval

func SetUpdateInterval(interval time.Duration) ResolverOption

SetUpdateInterval specifies the interval in which to run health checks.