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
|
package aws
import (
"encoding/json"
"io/ioutil"
"log"
"net/http"
"strings"
"time"
)
// DefaultEndpoint -
const DefaultEndpoint = "http://169.254.169.254"
// Ec2Meta -
type Ec2Meta struct {
Endpoint string
Client *http.Client
nonAWS bool
cache map[string]string
options ClientOptions
}
// NewEc2Meta -
func NewEc2Meta(options ClientOptions) *Ec2Meta {
return &Ec2Meta{cache: make(map[string]string), options: options}
}
// returnDefault -
func returnDefault(def []string) string {
if len(def) > 0 {
return def[0]
}
return ""
}
func unreachable(err error) bool {
if strings.Contains(err.Error(), "request canceled") ||
strings.Contains(err.Error(), "no route to host") ||
strings.Contains(err.Error(), "host is down") {
return true
}
return false
}
func (e *Ec2Meta) retrieveMetadata(url string, def ...string) string {
if value, ok := e.cache[url]; ok {
return value
}
if e.nonAWS {
return returnDefault(def)
}
if e.Client == nil {
timeout := e.options.Timeout
if timeout == 0 {
timeout = 500 * time.Millisecond
}
e.Client = &http.Client{Timeout: timeout}
}
resp, err := e.Client.Get(url)
if err != nil {
if unreachable(err) {
e.nonAWS = true
}
return returnDefault(def)
}
defer resp.Body.Close()
if resp.StatusCode > 399 {
return returnDefault(def)
}
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Fatalf("Failed to read response body from %s: %v", url, err)
}
value := strings.TrimSpace(string(body))
e.cache[url] = value
return value
}
// Meta -
func (e *Ec2Meta) Meta(key string, def ...string) string {
if e.Endpoint == "" {
e.Endpoint = DefaultEndpoint
}
url := e.Endpoint + "/latest/meta-data/" + key
return e.retrieveMetadata(url, def...)
}
// Dynamic -
func (e *Ec2Meta) Dynamic(key string, def ...string) string {
if e.Endpoint == "" {
e.Endpoint = DefaultEndpoint
}
url := e.Endpoint + "/latest/dynamic/" + key
return e.retrieveMetadata(url, def...)
}
// Region -
func (e *Ec2Meta) Region(def ...string) string {
defaultRegion := returnDefault(def)
if defaultRegion == "" {
defaultRegion = "unknown"
}
doc := e.Dynamic("instance-identity/document", `{"region":"`+defaultRegion+`"}`)
obj := &InstanceDocument{
Region: defaultRegion,
}
err := json.Unmarshal([]byte(doc), &obj)
if err != nil {
log.Fatalf("Unable to unmarshal JSON object %s: %v", doc, err)
}
return obj.Region
}
// InstanceDocument -
type InstanceDocument struct {
PrivateIP string `json:"privateIp"`
AvailabilityZone string `json:"availabilityZone"`
InstanceID string `json:"InstanceId"`
InstanceType string `json:"InstanceType"`
AccountID string `json:"AccountId"`
ImageID string `json:"imageId"`
Architecture string `json:"architecture"`
Region string `json:"region"`
}
|
