proxy

Documentation

Overview

Package proxy implements a forwarding proxy. It caches an upstream net.Conn for some time, so if the same client returns the upstream's Conn will be precached. Depending on how you benchmark this looks to be 50% faster than just opening a new connection for every client. It works with UDP and TCP and uses inband healthchecking.

Index

• Constants
• Variables
• type HealthChecker
  • func NewHealthChecker(proxyName, trans string, recursionDesired bool, domain string) HealthChecker
• type Options
• type Proxy
  • func NewProxy(proxyName, addr, trans string) *Proxy
  • func (p *Proxy) Addr() string
  • func (p *Proxy) Connect(ctx context.Context, state request.Request, opts Options) (*dns.Msg, error)
  • func (p *Proxy) Down(maxfails uint32) bool
  • func (p *Proxy) Fails() uint32
  • func (p *Proxy) GetHealthchecker() HealthChecker
  • func (p *Proxy) Healthcheck()
  • func (p *Proxy) SetExpire(expire time.Duration)
  • func (p *Proxy) SetReadTimeout(duration time.Duration)
  • func (p *Proxy) SetTLSConfig(cfg *tls.Config)
  • func (p *Proxy) Start(duration time.Duration)
  • func (p *Proxy) Stop()
• type Transport
  • func (t *Transport) Dial(proto string) (*persistConn, bool, error)
  • func (t *Transport) SetExpire(expire time.Duration)
  • func (t *Transport) SetTLSConfig(cfg *tls.Config)
  • func (t *Transport) Start()
  • func (t *Transport) Stop()
  • func (t *Transport) Yield(pc *persistConn)

Constants

const (
	ErrTransportStopped              = "proxy: transport stopped"
	ErrTransportStoppedDuringDial    = "proxy: transport stopped during dial"
	ErrTransportStoppedRetClosed     = "proxy: transport stopped, ret channel closed"
	ErrTransportStoppedDuringRetWait = "proxy: transport stopped during ret wait"
)

Variables

var (
	// ErrNoHealthy means no healthy proxies left.
	ErrNoHealthy = errors.New("no healthy proxies")
	// ErrNoForward means no forwarder defined.
	ErrNoForward = errors.New("no forwarder defined")
	// ErrCachedClosed means cached connection was closed by peer.
	ErrCachedClosed = errors.New("cached connection was closed by peer")
)

Types

type HealthChecker

type HealthChecker interface {
	Check(*Proxy) error
	SetTLSConfig(*tls.Config)
	GetTLSConfig() *tls.Config
	SetRecursionDesired(bool)
	GetRecursionDesired() bool
	SetDomain(domain string)
	GetDomain() string
	SetTCPTransport()
	GetReadTimeout() time.Duration
	SetReadTimeout(time.Duration)
	GetWriteTimeout() time.Duration
	SetWriteTimeout(time.Duration)
}

HealthChecker checks the upstream health.

func NewHealthChecker

func NewHealthChecker(proxyName, trans string, recursionDesired bool, domain string) HealthChecker

NewHealthChecker returns a new HealthChecker based on transport.

type Options

type Options struct {
	// ForceTCP use TCP protocol for upstream DNS request. Has precedence over PreferUDP flag
	ForceTCP bool
	// PreferUDP use UDP protocol for upstream DNS request.
	PreferUDP bool
	// HCRecursionDesired sets recursion desired flag for Proxy healthcheck requests
	HCRecursionDesired bool
	// HCDomain sets domain for Proxy healthcheck requests
	HCDomain string
}

Options holds various Options that can be set.

type Proxy

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

Proxy defines an upstream host.

func NewProxy

func NewProxy(proxyName, addr, trans string) *Proxy

NewProxy returns a new proxy.

func (*Proxy) Addr

func (p *Proxy) Addr() string

func (*Proxy) Connect

func (p *Proxy) Connect(ctx context.Context, state request.Request, opts Options) (*dns.Msg, error)

Connect selects an upstream, sends the request and waits for a response.

func (*Proxy) Down

func (p *Proxy) Down(maxfails uint32) bool

Down returns true if this proxy is down, i.e. has *more* fails than maxfails.

func (*Proxy) Fails

func (p *Proxy) Fails() uint32

func (*Proxy) GetHealthchecker

func (p *Proxy) GetHealthchecker() HealthChecker

func (*Proxy) Healthcheck

func (p *Proxy) Healthcheck()

Healthcheck kicks of a round of health checks for this proxy.

func (*Proxy) SetExpire

func (p *Proxy) SetExpire(expire time.Duration)

SetExpire sets the expire duration in the lower p.transport.

func (*Proxy) SetReadTimeout

func (p *Proxy) SetReadTimeout(duration time.Duration)

func (*Proxy) SetTLSConfig

func (p *Proxy) SetTLSConfig(cfg *tls.Config)

SetTLSConfig sets the TLS config in the lower p.transport and in the healthchecking client.

func (*Proxy) Start

func (p *Proxy) Start(duration time.Duration)

Start starts the proxy's healthchecking.

func (*Proxy) Stop

func (p *Proxy) Stop()

Stop close stops the health checking goroutine.

type Transport

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

Transport hold the persistent cache.

func (*Transport) Dial

func (t *Transport) Dial(proto string) (*persistConn, bool, error)

Dial dials the address configured in transport, potentially reusing a connection or creating a new one.

func (*Transport) SetExpire

func (t *Transport) SetExpire(expire time.Duration)

SetExpire sets the connection expire time in transport.

func (*Transport) SetTLSConfig

func (t *Transport) SetTLSConfig(cfg *tls.Config)

SetTLSConfig sets the TLS config in transport.

func (*Transport) Start

func (t *Transport) Start()

Start starts the transport's connection manager.

func (*Transport) Stop

func (t *Transport) Stop()

Stop stops the transport's connection manager.

func (*Transport) Yield

func (t *Transport) Yield(pc *persistConn)

Yield returns the connection to transport for reuse.