connector

-- import "github.com/hesmar/grpc-proxy/connector"

Package connector provides connection management strategies for gRPC proxies.

Usage

type CachingConnector

type CachingConnector struct {

	// OnConnect is an optional callback when a connection request is received.
	// Use for metrics integration.
	OnConnect func(addr string)
	// OnCacheMiss is an optional callback when a new connection will be
	// established.  Use for metrics integration.
	OnCacheMiss func(addr string)
	// OnConnectionCountUpdate is an optional callback which provides the
	// total active connection count.  Use for metrics integration.
	OnConnectionCountUpdate func(count int)
}

CachingConnector is a caching creator of rpc connections, keyed by address.

func NewCachingConnector

func NewCachingConnector(opts ...Opt) *CachingConnector

NewCachingConnector returns a new connection cache instance. Connections will be cached and reused between calls.

The provided dialer is used to create new gRPC connections. This may be a grpc.Dialer.

To use, use CachingConnector.Dial instead of grpc.Dial when creating connections to remote endpoints. CachingConnector.Release must be called once for each successful Dial call.

Note that CachingConnector.Expire must be called periodically in order to free unused resources. Any connection which has been inactive for 2 consecutive Expire calls will be closed.

func (*CachingConnector) CloseOnRelease

func (c *CachingConnector) CloseOnRelease(addr string) bool

CloseOnRelease moves any connection associated with the given address to the cleanup list, where it will be closed by Expire as soon as the reference count reaches zero.

It is not normally necessary to call this function, as unused connections are closed automatically over time.

func (*CachingConnector) Dial

func (c *CachingConnector) Dial(ctx context.Context, addr string) (*grpc.ClientConn, error)

Dial establishes a connection or returns a cached entry. Close must be called on the returned value, if not nil.

Dial options are not supported, since they would be ignored if a cached connection is used.

func (*CachingConnector) Expire

func (c *CachingConnector) Expire() []string

Expire cleans up old connections.

This must be called periodically for proper functioning of CachedConnection.

func (*CachingConnector) Release

func (c *CachingConnector) Release(addr string, conn *grpc.ClientConn)

Release allows unused resources to be freed. Must be called once per successful call to Connect.

type Opt

type Opt func(*CachingConnector)

Opt is an option to NewCachingConnector.

func WithDialer

func WithDialer(dialer func(ctx context.Context, target string, opts ...grpc.DialOption) (*grpc.ClientConn, error)) Opt

WithDialer specifies a customer dialer for the caching connector.