bootstrap

Documentation

Overview

Package bootstrap provides types and functions to resolve upstream hostnames and to dial retrieved addresses.

Index

• Constants
• func LookupParallel(ctx context.Context, resolvers []Resolver, host string) (addrs []netip.Addr, err error)
• type DialHandler
  • func NewDialContext(timeout time.Duration, addrs ...string) (h DialHandler)
  • func ResolveDialContext(u *url.URL, timeout time.Duration, resolvers []Resolver, preferIPv6 bool) (h DialHandler, err error)
• type Resolver

Constants

const ErrNoResolvers errors.Error = "no resolvers specified"

ErrNoResolvers is returned when zero resolvers specified.

Functions

func LookupParallel

func LookupParallel(
	ctx context.Context,
	resolvers []Resolver,
	host string,
) (addrs []netip.Addr, err error)

LookupParallel performs lookup for IP address of host with all resolvers concurrently.

Types

type DialHandler

type DialHandler func(ctx context.Context, network, addr string) (conn net.Conn, err error)

DialHandler is a dial function for creating unencrypted network connections to the upstream server. It establishes the connection to the server specified at initialization and ignores the addr.

func NewDialContext

func NewDialContext(timeout time.Duration, addrs ...string) (h DialHandler)

NewDialContext returns a DialHandler that dials addrs and returns the first successful connection. At least a single addr should be specified.

TODO(e.burkov): Consider using Resolver instead of [upstream.Options.Bootstrap] and [upstream.Options.ServerIPAddrs].

func ResolveDialContext

func ResolveDialContext(
	u *url.URL,
	timeout time.Duration,
	resolvers []Resolver,
	preferIPv6 bool,
) (h DialHandler, err error)

ResolveDialContext returns a DialHandler that uses addresses resolved from u using resolvers. u must not be nil.

type Resolver

type Resolver interface {
	// LookupIPAddr looks up the IP addresses for the given host.  network must
	// be one of "ip", "ip4" or "ip6".
	LookupNetIP(ctx context.Context, network string, host string) (addrs []netip.Addr, err error)
}

Resolver resolves the hostnames to IP addresses.