diff options
Diffstat (limited to 'modules/caddyhttp/reverseproxy')
| -rw-r--r-- | modules/caddyhttp/reverseproxy/httptransport.go | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/modules/caddyhttp/reverseproxy/httptransport.go b/modules/caddyhttp/reverseproxy/httptransport.go index 327cc89..dce7b9e 100644 --- a/modules/caddyhttp/reverseproxy/httptransport.go +++ b/modules/caddyhttp/reverseproxy/httptransport.go @@ -21,6 +21,7 @@ import ( "encoding/base64" "fmt" "io/ioutil" + weakrand "math/rand" "net" "net/http" "reflect" @@ -43,6 +44,9 @@ type HTTPTransport struct { // able to borrow/use at least some of these config fields; if so, // maybe move them into a type called CommonTransport and embed it? + // Configures the DNS resolver used to resolve the IP address of upstream hostnames. + Resolver *UpstreamResolver `json:"resolver,omitempty"` + // Configures TLS to the upstream. Setting this to an empty struct // is sufficient to enable TLS with reasonable defaults. TLS *TLSConfig `json:"tls,omitempty"` @@ -146,7 +150,30 @@ func (h *HTTPTransport) NewTransport(ctx caddy.Context) (*http.Transport, error) dialer := &net.Dialer{ Timeout: time.Duration(h.DialTimeout), FallbackDelay: time.Duration(h.FallbackDelay), - // TODO: Resolver + } + + if h.Resolver != nil { + for _, v := range h.Resolver.Addresses { + addr, err := caddy.ParseNetworkAddress(v) + if err != nil { + return nil, err + } + if addr.PortRangeSize() != 1 { + return nil, fmt.Errorf("resolver address must have exactly one address; cannot call %v", addr) + } + h.Resolver.netAddrs = append(h.Resolver.netAddrs, addr) + } + d := &net.Dialer{ + Timeout: time.Duration(h.DialTimeout), + FallbackDelay: time.Duration(h.FallbackDelay), + } + dialer.Resolver = &net.Resolver{ + PreferGo: true, + Dial: func(ctx context.Context, _, _ string) (net.Conn, error) { + addr := h.Resolver.netAddrs[weakrand.Intn(len(h.Resolver.netAddrs))] + return d.DialContext(ctx, addr.Network, addr.JoinHostPort(0)) + }, + } } rt := &http.Transport{ @@ -359,6 +386,18 @@ func (t TLSConfig) MakeTLSClientConfig(ctx caddy.Context) (*tls.Config, error) { return cfg, nil } +// UpstreamResolver holds the set of addresses of DNS resolvers of +// upstream addresses +type UpstreamResolver struct { + // The addresses of DNS resolvers to use when looking up the addresses of proxy upstreams. + // It accepts [network addresses](/docs/conventions#network-addresses) + // with port range of only 1. If the host is an IP address, it will be dialed directly to resolve the upstream server. + // If the host is not an IP address, the addresses are resolved using the [name resolution convention](https://golang.org/pkg/net/#hdr-Name_Resolution) of the Go standard library. + // If the array contains more than 1 resolver address, one is chosen at random. + Addresses []string `json:"addresses,omitempty"` + netAddrs []caddy.NetworkAddress +} + // KeepAlive holds configuration pertaining to HTTP Keep-Alive. type KeepAlive struct { // Whether HTTP Keep-Alive is enabled. Default: true |