github-mirror/caddy
2
0
Fork 0
mirror of https://github.com/caddyserver/caddy.git synced 2025-05-28 06:40:01 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

reverse_proxy: Add support for SRV backends (#3180)

Browse Source 
* reverse_proxy: Begin SRV lookup support (WIP)

* reverse_proxy: Finish adding support for SRV-based backends (#3179)
This commit is contained in:
Matt Holt
2020-03-24 10:53:53 -06:00
committed by GitHub
parent 95b2863df2
commit e02117cb8a
4 changed files with 78 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

73
modules/caddyhttp/reverseproxy/hosts.go
View File

@ -17,6 +17,8 @@ package reverseproxy
import (
"context"
"fmt"
"net"
"net/http"
"strconv"
"sync/atomic"
@ -63,10 +65,10 @@ type UpstreamPool []*Upstream
type Upstream struct {
Host `json:"-"`
// The [network address](/docs/json/apps/http/#servers/listen)
// The [network address](/docs/conventions#network-addresses)
// to dial to connect to the upstream. Must represent precisely
// one socket (i.e. no port ranges). A valid network address
// either has a host and port, or is a unix socket address.
// either has a host and port or is a unix socket address.
//
// Placeholders may be used to make the upstream dynamic, but be
// aware of the health check implications of this: a single
@ -75,6 +77,11 @@ type Upstream struct {
// backends is down. Also be aware of open proxy vulnerabilities.
Dial string `json:"dial,omitempty"`
// If DNS SRV records are used for service discovery with this
// upstream, specify the DNS name for which to look up SRV
// records here, instead of specifying a dial address.
LookupSRV string `json:"lookup_srv,omitempty"`
// The maximum number of simultaneous requests to allow to
// this upstream. If set, overrides the global passive health
// check UnhealthyRequestCount value.
@ -118,6 +125,47 @@ func (u *Upstream) Full() bool {
return u.MaxRequests > 0 && u.Host.NumRequests() >= u.MaxRequests
}
// fillDialInfo returns a filled DialInfo for upstream u, using the request
// context. If the upstream has a SRV lookup configured, that is done and a
// returned address is chosen; otherwise, the upstream's regular dial address
// field is used. Note that the returned value is not a pointer.
func (u *Upstream) fillDialInfo(r *http.Request) (DialInfo, error) {
repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
var addr caddy.ParsedAddress
if u.LookupSRV != "" {
// perform DNS lookup for SRV records and choose one
srvName := repl.ReplaceAll(u.LookupSRV, "")
_, records, err := net.DefaultResolver.LookupSRV(r.Context(), "", "", srvName)
if err != nil {
return DialInfo{}, err
}
addr.Network = "tcp"
addr.Host = records[0].Target
addr.StartPort, addr.EndPort = uint(records[0].Port), uint(records[0].Port)
} else {
// use provided dial address
var err error
dial := repl.ReplaceAll(u.Dial, "")
addr, err = caddy.ParseNetworkAddress(dial)
if err != nil {
return DialInfo{}, fmt.Errorf("upstream %s: invalid dial address %s: %v", u.Dial, dial, err)
}
if numPorts := addr.PortRangeSize(); numPorts != 1 {
return DialInfo{}, fmt.Errorf("upstream %s: dial address must represent precisely one socket: %s represents %d",
u.Dial, dial, numPorts)
}
}
return DialInfo{
Upstream: u,
Network: addr.Network,
Address: addr.JoinHostPort(0),
Host: addr.Host,
Port: strconv.Itoa(int(addr.StartPort)),
}, nil
}
// upstreamHost is the basic, in-memory representation
// of the state of a remote host. It implements the
// Host interface.
@ -204,27 +252,6 @@ func (di DialInfo) String() string {
return caddy.JoinNetworkAddress(di.Network, di.Host, di.Port)
}
// fillDialInfo returns a filled DialInfo for the given upstream, using
// the given Replacer. Note that the returned value is not a pointer.
func fillDialInfo(upstream *Upstream, repl *caddy.Replacer) (DialInfo, error) {
dial := repl.ReplaceAll(upstream.Dial, "")
addr, err := caddy.ParseNetworkAddress(dial)
if err != nil {
return DialInfo{}, fmt.Errorf("upstream %s: invalid dial address %s: %v", upstream.Dial, dial, err)
}
if numPorts := addr.PortRangeSize(); numPorts != 1 {
return DialInfo{}, fmt.Errorf("upstream %s: dial address must represent precisely one socket: %s represents %d",
upstream.Dial, dial, numPorts)
}
return DialInfo{
Upstream: upstream,
Network: addr.Network,
Address: addr.JoinHostPort(0),
Host: addr.Host,
Port: strconv.Itoa(int(addr.StartPort)),
}, nil
}
// GetDialInfo gets the upstream dialing info out of the context,
// and returns true if there was a valid value; false otherwise.
func GetDialInfo(ctx context.Context) (DialInfo, bool) {