-
Notifications
You must be signed in to change notification settings - Fork 4
/
forwarder.go
189 lines (158 loc) · 4.72 KB
/
forwarder.go
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
177
178
179
180
181
182
183
184
185
186
187
188
189
package main
import (
"fmt"
"io/ioutil"
"net/http"
"net/http/httputil"
"net/url"
"regexp"
"strings"
"github.com/labstack/echo/v4"
"github.com/rs/zerolog/log"
)
var (
ErrNoMatchFound = fmt.Errorf("No match found")
)
// forwarder forwads requests to real petasos instance and does
// apropriate replacements.
func forwarder(c echo.Context) error {
log.Debug().Msg("##############################")
log.Debug().Msg("###### Request Start #########")
log.Debug().Msg("##############################")
// prepare request for forwarding
req := c.Request()
// store scheme of original request
originalRequestScheme := req.URL.Scheme
if originalRequestScheme == "" {
originalRequestScheme = req.Header.Get("X-Forwarded-Proto")
}
log.Debug().Msgf("originalScheme [%s]", originalRequestScheme)
// Change protocols from ws(s) => http(s).
// Parodus makes requests to `ws` but complains
// when getting a redirect containing `ws`.
switch originalRequestScheme {
case "ws":
log.Debug().Msgf("Replacing original scheme [%s] with [%s] in output", originalRequestScheme, "http")
originalRequestScheme = "http"
case "wss":
log.Debug().Msgf("Replacing original scheme [%s] with [%s] in output", originalRequestScheme, "https")
originalRequestScheme = "https"
}
dump, err := httputil.DumpRequest(req, true)
if err != nil {
return err
}
log.Debug().Msg("Dumping original request to petasos-rewriter")
log.Debug().Msgf("%s", dump)
log.Debug().Msg("") // br
log.Debug().Msg("") // br
// Prepare forwarding to petasos
req.URL = &url.URL{
Scheme: petasosURL.Scheme,
Host: petasosURL.Host,
Path: req.URL.Path,
}
req.RequestURI = ""
// Forward to real petasos
client := &http.Client{
CheckRedirect: func(req *http.Request, via []*http.Request) error {
return http.ErrUseLastResponse
},
}
dump, err = httputil.DumpRequest(req, true)
if err != nil {
return err
}
log.Debug().Msg("Dumping request to real petasos")
log.Debug().Msgf("%s", dump)
log.Debug().Msg("") // br
log.Debug().Msg("") // br
resp, err := client.Do(req)
if err != nil {
return err
}
dump, err = httputil.DumpResponse(resp, true)
if err != nil {
return err
}
log.Debug().Msg("Dumping response from real petasos")
log.Debug().Msgf("%s", dump)
log.Debug().Msg("") // br
log.Debug().Msg("") // br
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return err
}
// just printing the all response headers which we got from actual petasos
for k, v := range resp.Header {
var header string
for _, s := range v {
if header != "" {
header = header + ","
}
header = header + s
}
header = strings.TrimRight(header, ",")
c.Response().Header().Set(k, header)
log.Debug().Msgf("k: %s, v: %s\n", k, v)
}
// Replace location header
location := c.Response().Header().Get("Location")
log.Debug().Msgf("Location [%s]\n", location)
locationUrl, err := url.Parse(location)
if err != nil {
return err
}
if *fixedScheme != "" {
// TODO: use scheme from publicTalariaURL and make fixedScheme bool
// locationUrl.Scheme = publicTalariaURL.Scheme
locationUrl.Scheme = *fixedScheme
} else {
locationUrl.Scheme = originalRequestScheme
}
// Do replacement & build public talaria url
externalTalariaName, err := resplaceTalariaInternalName(
locationUrl.Hostname(),
*talariaInternalName,
*talariaExternalName,
)
if err != nil {
return err
}
publicTalariaURL := buildExternalURL(externalTalariaName, *talariaDomain)
locationUrl.Host = publicTalariaURL
log.Info().Msgf("redirecting from Location [%s] to Location [%s] \n", location, locationUrl.String())
c.Response().Header().Set("Location", locationUrl.String())
// Replace url in body
var href = regexp.MustCompile(`"(.*)"`)
body = href.ReplaceAll(body, []byte(`"`+locationUrl.String()+`"`))
c.Response().Header().Set("Content-Length", fmt.Sprintf("%d", len(body)))
// Forward status code
c.Response().Writer.WriteHeader(resp.StatusCode)
_, err = c.Response().Writer.Write(body)
if err != nil {
return err
}
return nil
}
// resplaceTalariaInternalName replaces internal talaria name.
// Returns a ErrNoMatchFound when replacement is impossible.
func resplaceTalariaInternalName(host, old, new string) (string, error) {
index := strings.Index(host, old)
if index == -1 {
return "", ErrNoMatchFound
}
talariaExternal := strings.Replace(host, old, new, -1)
// TODO: strip possible internal k8s namespace.
// xmidt-talaria OK
// talaria.xmidt Not OK
return talariaExternal, nil
}
// buildExternalURL by concatenation new talaria name + given domain
func buildExternalURL(newTalariaName, domain string) string {
var builder strings.Builder
builder.WriteString(newTalariaName)
builder.WriteString(".")
builder.WriteString(domain)
return builder.String()
}