/
document.go
98 lines (87 loc) · 2.91 KB
/
document.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
// Copyright 2018 Capital One Services, LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package ec2metadata
import (
"crypto/sha1"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"strings"
"github.com/rs/zerolog/log"
)
// A Document provides a struct for EC2 instance identity documents to be
// unmarshaled.
type Document struct {
AvailabilityZone string `json:"availabilityZone"`
Region string `json:"region"`
InstanceId string `json:"instanceId"`
AccountId string `json:"accountId"`
InstanceType string `json:"instanceType"`
ImageId string `json:"imageId"`
}
// Name returns the logical name for the instance described in the identity
// document and is the value used when deriving the unique identifier hash.
func (d *Document) Name() string {
return fmt.Sprintf("%s-%s", d.AccountId, d.InstanceId)
}
func (d *Document) Hash() string {
return strings.ToUpper(fmt.Sprintf("%x", sha1.Sum([]byte(d.Name()))))
}
const (
// The EC2 metadata service URL for the instance identity document.
IdentityDocumentURL = "http://169.254.169.254/latest/dynamic/instance-identity/document"
// The EC2 metadata service URL for the instance identity document signature (RSA SHA256).
IdentitySignatureURL = "http://169.254.169.254/latest/dynamic/instance-identity/signature"
)
// GetLocalInstanceDocument returns the instance identity document from the EC2
// metadata service.
func GetLocalInstanceDocument() []byte {
resp, err := http.Get(IdentityDocumentURL)
if err != nil {
log.Debug().Err(err).Msg("cannot get instance document")
return nil
}
defer resp.Body.Close()
data, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Debug().Err(err).Msg("cannot get instance document")
return nil
}
return data
}
func GetLocalInstanceRegion() string {
var d Document
if err := json.Unmarshal(GetLocalInstanceDocument(), &d); err != nil {
log.Debug().Err(err).Msg("invalid instance document")
return ""
}
return d.Region
}
// GetLocalInstanceDocument returns the signature for the instance identity
// document from the EC2 metadata service.
func GetLocalInstanceSignature() []byte {
resp, err := http.Get(IdentitySignatureURL)
if err != nil {
log.Debug().Err(err).Msg("cannot get instance document")
return nil
}
defer resp.Body.Close()
data, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Debug().Err(err).Msg("cannot get instance document")
return nil
}
return data
}