Refactor proxy middleware so that 1.) From() is exposed 2.) Other upstreams can be implemented/plugged in

config/setup/proxy.go

@@ -1,19 +1,13 @@
 package setup
 
 import (
-	"net/http"
-	"net/url"
-	"strconv"
-	"strings"
-	"time"
-
 	"github.com/mholt/caddy/middleware"
 	"github.com/mholt/caddy/middleware/proxy"
 )
 
 // Proxy configures a new Proxy middleware instance.
 func Proxy(c *Controller) (middleware.Middleware, error) {
-	if upstreams, err := newStaticUpstreams(c); err == nil {
+	if upstreams, err := proxy.NewStaticUpstreams(c.Dispenser); err == nil {
 		return func(next middleware.Handler) middleware.Handler {
 			return proxy.Proxy{Next: next, Upstreams: upstreams}
 		}, nil
@@ -21,125 +15,3 @@ func Proxy(c *Controller) (middleware.Middleware, error) {
 		return nil, err
 	}
 }
-
-// newStaticUpstreams parses the configuration input and sets up
-// static upstreams for the proxy middleware.
-func newStaticUpstreams(c *Controller) ([]proxy.Upstream, error) {
-	var upstreams []proxy.Upstream
-
-	for c.Next() {
-		upstream := &proxy.StaticUpstream{
-			From:        "",
-			Hosts:       nil,
-			Policy:      &proxy.Random{},
-			FailTimeout: 10 * time.Second,
-			MaxFails:    1,
-		}
-		var proxyHeaders http.Header
-		if !c.Args(&upstream.From) {
-			return upstreams, c.ArgErr()
-		}
-		to := c.RemainingArgs()
-		if len(to) == 0 {
-			return upstreams, c.ArgErr()
-		}
-
-		for c.NextBlock() {
-			switch c.Val() {
-			case "policy":
-				if !c.NextArg() {
-					return upstreams, c.ArgErr()
-				}
-				switch c.Val() {
-				case "random":
-					upstream.Policy = &proxy.Random{}
-				case "round_robin":
-					upstream.Policy = &proxy.RoundRobin{}
-				case "least_conn":
-					upstream.Policy = &proxy.LeastConn{}
-				default:
-					return upstreams, c.ArgErr()
-				}
-			case "fail_timeout":
-				if !c.NextArg() {
-					return upstreams, c.ArgErr()
-				}
-				if dur, err := time.ParseDuration(c.Val()); err == nil {
-					upstream.FailTimeout = dur
-				} else {
-					return upstreams, err
-				}
-			case "max_fails":
-				if !c.NextArg() {
-					return upstreams, c.ArgErr()
-				}
-				if n, err := strconv.Atoi(c.Val()); err == nil {
-					upstream.MaxFails = int32(n)
-				} else {
-					return upstreams, err
-				}
-			case "health_check":
-				if !c.NextArg() {
-					return upstreams, c.ArgErr()
-				}
-				upstream.HealthCheck.Path = c.Val()
-				upstream.HealthCheck.Interval = 30 * time.Second
-				if c.NextArg() {
-					if dur, err := time.ParseDuration(c.Val()); err == nil {
-						upstream.HealthCheck.Interval = dur
-					} else {
-						return upstreams, err
-					}
-				}
-			case "proxy_header":
-				var header, value string
-				if !c.Args(&header, &value) {
-					return upstreams, c.ArgErr()
-				}
-				if proxyHeaders == nil {
-					proxyHeaders = make(map[string][]string)
-				}
-				proxyHeaders.Add(header, value)
-			}
-		}
-
-		upstream.Hosts = make([]*proxy.UpstreamHost, len(to))
-		for i, host := range to {
-			if !strings.HasPrefix(host, "http") {
-				host = "http://" + host
-			}
-			uh := &proxy.UpstreamHost{
-				Name:         host,
-				Conns:        0,
-				Fails:        0,
-				FailTimeout:  upstream.FailTimeout,
-				Unhealthy:    false,
-				ExtraHeaders: proxyHeaders,
-				CheckDown: func(upstream *proxy.StaticUpstream) proxy.UpstreamHostDownFunc {
-					return func(uh *proxy.UpstreamHost) bool {
-						if uh.Unhealthy {
-							return true
-						}
-						if uh.Fails >= upstream.MaxFails &&
-							upstream.MaxFails != 0 {
-							return true
-						}
-						return false
-					}
-				}(upstream),
-			}
-			if baseUrl, err := url.Parse(uh.Name); err == nil {
-				uh.ReverseProxy = proxy.NewSingleHostReverseProxy(baseUrl)
-			} else {
-				return upstreams, err
-			}
-			upstream.Hosts[i] = uh
-		}
-
-		if upstream.HealthCheck.Path != "" {
-			go upstream.HealthCheckWorker(nil)
-		}
-		upstreams = append(upstreams, upstream)
-	}
-	return upstreams, nil
-}

middleware/proxy/proxy.go

@@ -23,7 +23,7 @@ type Proxy struct {
 // suitable upstream host, or nil if no such hosts are available.
 type Upstream interface {
 	//The path this upstream host should be routed on
-	from() string
+	From() string
 	// Selects an upstream host to be routed to.
 	Select() *UpstreamHost
 }
@@ -55,7 +55,7 @@ func (uh *UpstreamHost) Down() bool {
 func (p Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 
 	for _, upstream := range p.Upstreams {
-		if middleware.Path(r.URL.Path).Matches(upstream.from()) {
+		if middleware.Path(r.URL.Path).Matches(upstream.From()) {
 			var replacer middleware.Replacer
 			start := time.Now()
 			requestHost := r.Host

middleware/proxy/upstream.go

@@ -1,14 +1,18 @@
 package proxy
 
 import (
+	"github.com/mholt/caddy/config/parse"
 	"io"
 	"io/ioutil"
 	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
 	"time"
 )
 
-type StaticUpstream struct {
+type staticUpstream struct {
-	From   string
+	from   string
 	Hosts  HostPool
 	Policy Policy
 
@@ -20,11 +24,133 @@ type StaticUpstream struct {
 	}
 }
 
-func (u *StaticUpstream) from() string {
+// newStaticUpstreams parses the configuration input and sets up
-	return u.From
+// static upstreams for the proxy middleware.
+func NewStaticUpstreams(c parse.Dispenser) ([]Upstream, error) {
+	var upstreams []Upstream
+
+	for c.Next() {
+		upstream := &staticUpstream{
+			from:        "",
+			Hosts:       nil,
+			Policy:      &Random{},
+			FailTimeout: 10 * time.Second,
+			MaxFails:    1,
+		}
+		var proxyHeaders http.Header
+		if !c.Args(&upstream.from) {
+			return upstreams, c.ArgErr()
+		}
+		to := c.RemainingArgs()
+		if len(to) == 0 {
+			return upstreams, c.ArgErr()
+		}
+
+		for c.NextBlock() {
+			switch c.Val() {
+			case "policy":
+				if !c.NextArg() {
+					return upstreams, c.ArgErr()
+				}
+				switch c.Val() {
+				case "random":
+					upstream.Policy = &Random{}
+				case "round_robin":
+					upstream.Policy = &RoundRobin{}
+				case "least_conn":
+					upstream.Policy = &LeastConn{}
+				default:
+					return upstreams, c.ArgErr()
+				}
+			case "fail_timeout":
+				if !c.NextArg() {
+					return upstreams, c.ArgErr()
+				}
+				if dur, err := time.ParseDuration(c.Val()); err == nil {
+					upstream.FailTimeout = dur
+				} else {
+					return upstreams, err
+				}
+			case "max_fails":
+				if !c.NextArg() {
+					return upstreams, c.ArgErr()
+				}
+				if n, err := strconv.Atoi(c.Val()); err == nil {
+					upstream.MaxFails = int32(n)
+				} else {
+					return upstreams, err
+				}
+			case "health_check":
+				if !c.NextArg() {
+					return upstreams, c.ArgErr()
+				}
+				upstream.HealthCheck.Path = c.Val()
+				upstream.HealthCheck.Interval = 30 * time.Second
+				if c.NextArg() {
+					if dur, err := time.ParseDuration(c.Val()); err == nil {
+						upstream.HealthCheck.Interval = dur
+					} else {
+						return upstreams, err
+					}
+				}
+			case "proxy_header":
+				var header, value string
+				if !c.Args(&header, &value) {
+					return upstreams, c.ArgErr()
+				}
+				if proxyHeaders == nil {
+					proxyHeaders = make(map[string][]string)
+				}
+				proxyHeaders.Add(header, value)
+			}
+		}
+
+		upstream.Hosts = make([]*UpstreamHost, len(to))
+		for i, host := range to {
+			if !strings.HasPrefix(host, "http") {
+				host = "http://" + host
+			}
+			uh := &UpstreamHost{
+				Name:         host,
+				Conns:        0,
+				Fails:        0,
+				FailTimeout:  upstream.FailTimeout,
+				Unhealthy:    false,
+				ExtraHeaders: proxyHeaders,
+				CheckDown: func(upstream *staticUpstream) UpstreamHostDownFunc {
+					return func(uh *UpstreamHost) bool {
+						if uh.Unhealthy {
+							return true
+						}
+						if uh.Fails >= upstream.MaxFails &&
+							upstream.MaxFails != 0 {
+							return true
+						}
+						return false
+					}
+				}(upstream),
+			}
+			if baseUrl, err := url.Parse(uh.Name); err == nil {
+				uh.ReverseProxy = NewSingleHostReverseProxy(baseUrl)
+			} else {
+				return upstreams, err
+			}
+			upstream.Hosts[i] = uh
+		}
+
+		if upstream.HealthCheck.Path != "" {
+			go upstream.HealthCheckWorker(nil)
+		}
+		upstreams = append(upstreams, upstream)
+	}
+	return upstreams, nil
 }
 
-func (u *StaticUpstream) healthCheck() {
+func (u *staticUpstream) From() string {
+	return u.from
+}
+
+func (u *staticUpstream) healthCheck() {
 	for _, host := range u.Hosts {
 		hostUrl := host.Name + u.HealthCheck.Path
 		if r, err := http.Get(hostUrl); err == nil {
@@ -37,7 +163,7 @@ func (u *StaticUpstream) healthCheck() {
 	}
 }
 
-func (u *StaticUpstream) HealthCheckWorker(stop chan struct{}) {
+func (u *staticUpstream) HealthCheckWorker(stop chan struct{}) {
 	ticker := time.NewTicker(u.HealthCheck.Interval)
 	u.healthCheck()
 	for {
@@ -52,7 +178,7 @@ func (u *StaticUpstream) HealthCheckWorker(stop chan struct{}) {
 	}
 }
 
-func (u *StaticUpstream) Select() *UpstreamHost {
+func (u *staticUpstream) Select() *UpstreamHost {
 	pool := u.Hosts
 	if len(pool) == 1 {
 		if pool[0].Down() {