1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
package middleware
import (
"fmt"
"io"
"math/rand"
"net"
"net/http"
"net/http/httputil"
"net/url"
"sync/atomic"
"time"
"github.com/labstack/echo"
)
// TODO: Handle TLS proxy
type (
// ProxyConfig defines the config for Proxy middleware.
ProxyConfig struct {
// Skipper defines a function to skip middleware.
Skipper Skipper
// Balancer defines a load balancing technique.
// Required.
// Possible values:
// - RandomBalancer
// - RoundRobinBalancer
Balancer ProxyBalancer
}
// ProxyTarget defines the upstream target.
ProxyTarget struct {
URL *url.URL
}
// RandomBalancer implements a random load balancing technique.
RandomBalancer struct {
Targets []*ProxyTarget
random *rand.Rand
}
// RoundRobinBalancer implements a round-robin load balancing technique.
RoundRobinBalancer struct {
Targets []*ProxyTarget
i uint32
}
// ProxyBalancer defines an interface to implement a load balancing technique.
ProxyBalancer interface {
Next() *ProxyTarget
}
)
var (
// DefaultProxyConfig is the default Proxy middleware config.
DefaultProxyConfig = ProxyConfig{
Skipper: DefaultSkipper,
}
)
func proxyHTTP(t *ProxyTarget) http.Handler {
return httputil.NewSingleHostReverseProxy(t.URL)
}
func proxyRaw(t *ProxyTarget, c echo.Context) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
in, _, err := c.Response().Hijack()
if err != nil {
c.Error(fmt.Errorf("proxy raw, hijack error=%v, url=%s", t.URL, err))
return
}
defer in.Close()
out, err := net.Dial("tcp", t.URL.Host)
if err != nil {
he := echo.NewHTTPError(http.StatusBadGateway, fmt.Sprintf("proxy raw, dial error=%v, url=%s", t.URL, err))
c.Error(he)
return
}
defer out.Close()
// Write header
err = r.Write(out)
if err != nil {
he := echo.NewHTTPError(http.StatusBadGateway, fmt.Sprintf("proxy raw, request header copy error=%v, url=%s", t.URL, err))
c.Error(he)
return
}
errc := make(chan error, 2)
cp := func(dst io.Writer, src io.Reader) {
_, err := io.Copy(dst, src)
errc <- err
}
go cp(out, in)
go cp(in, out)
err = <-errc
if err != nil && err != io.EOF {
c.Logger().Errorf("proxy raw, copy body error=%v, url=%s", t.URL, err)
}
})
}
// Next randomly returns an upstream target.
func (r *RandomBalancer) Next() *ProxyTarget {
if r.random == nil {
r.random = rand.New(rand.NewSource(int64(time.Now().Nanosecond())))
}
return r.Targets[r.random.Intn(len(r.Targets))]
}
// Next returns an upstream target using round-robin technique.
func (r *RoundRobinBalancer) Next() *ProxyTarget {
r.i = r.i % uint32(len(r.Targets))
t := r.Targets[r.i]
atomic.AddUint32(&r.i, 1)
return t
}
// Proxy returns a Proxy middleware.
//
// Proxy middleware forwards the request to upstream server using a configured load balancing technique.
func Proxy(balancer ProxyBalancer) echo.MiddlewareFunc {
c := DefaultProxyConfig
c.Balancer = balancer
return ProxyWithConfig(c)
}
// ProxyWithConfig returns a Proxy middleware with config.
// See: `Proxy()`
func ProxyWithConfig(config ProxyConfig) echo.MiddlewareFunc {
// Defaults
if config.Skipper == nil {
config.Skipper = DefaultLoggerConfig.Skipper
}
if config.Balancer == nil {
panic("echo: proxy middleware requires balancer")
}
return func(next echo.HandlerFunc) echo.HandlerFunc {
return func(c echo.Context) (err error) {
if config.Skipper(c) {
return next(c)
}
req := c.Request()
res := c.Response()
tgt := config.Balancer.Next()
// Fix header
if req.Header.Get(echo.HeaderXRealIP) == "" {
req.Header.Set(echo.HeaderXRealIP, c.RealIP())
}
if req.Header.Get(echo.HeaderXForwardedProto) == "" {
req.Header.Set(echo.HeaderXForwardedProto, c.Scheme())
}
if c.IsWebSocket() && req.Header.Get(echo.HeaderXForwardedFor) == "" { // For HTTP, it is automatically set by Go HTTP reverse proxy.
req.Header.Set(echo.HeaderXForwardedFor, c.RealIP())
}
// Proxy
switch {
case c.IsWebSocket():
proxyRaw(tgt, c).ServeHTTP(res, req)
case req.Header.Get(echo.HeaderAccept) == "text/event-stream":
default:
proxyHTTP(tgt).ServeHTTP(res, req)
}
return
}
}
}
|
