├── Readme.md
└── main.go


/Readme.md:
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 1 | 
 2 | # sdns-ec2
 3 | 
 4 |  EC2 resolver for [SDNS](https://github.com/tj/sdns).
 5 | 
 6 | ## Installation
 7 | 
 8 |  Via binary [releases](https://github.com/tj/sdns-ec2/releases) or:
 9 | 
10 | ```
11 | $ go get github.com/tj/sdns-ec2
12 | ```
13 | 
14 | ## Example
15 | 
16 | Config:
17 | 
18 | ```
19 | bind: ":5000"
20 | upstream:
21 |   - 8.8.8.8
22 |   - 8.8.4.4
23 | domains:
24 |   - name: ec2.local.
25 |     command: sdns-ec2
26 |   - name: ec2.
27 |     command: sdns-ec2 --region us-west-1 --ttl 600
28 | ```
29 | 
30 | dig:
31 | 
32 | ```
33 | $ dig @127.0.0.1 -p 5000 +short site-02.ec2
34 | 10.30.41.228
35 | ```
36 | 
37 | # License
38 | 
39 | MIT


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/main.go:
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 1 | package main
 2 | 
 3 | import "github.com/awslabs/aws-sdk-go/aws/credentials"
 4 | import "github.com/awslabs/aws-sdk-go/service/ec2"
 5 | import "github.com/awslabs/aws-sdk-go/aws"
 6 | import "github.com/tj/docopt"
 7 | import "github.com/tj/sdns"
 8 | import "strconv"
 9 | import "log"
10 | import "os"
11 | 
12 | var Version = "0.0.1"
13 | 
14 | const Usage = `
15 |   Usage:
16 |     sdns-ec2 [--region name] [--ttl n]
17 |     sdns-ec2 -h | --help
18 |     sdns-ec2 --version
19 | 
20 |   Options:
21 |     --ttl n          record ttl [default: 300]
22 |     --region name    aws region [default: us-west-2]
23 |     -h, --help       output help information
24 |     -v, --version    output version
25 | 
26 | `
27 | 
28 | func main() {
29 | 	log := log.New(os.Stderr, "", 0)
30 | 
31 | 	args, err := docopt.Parse(Usage, nil, true, Version, false)
32 | 	if err != nil {
33 | 		log.Fatalf("error: %s", err)
34 | 	}
35 | 
36 | 	question, err := sdns.Read(os.Stdin)
37 | 	if err != nil {
38 | 		log.Fatalf("error parsing stdin: %s", err)
39 | 	}
40 | 
41 | 	ttl, err := strconv.Atoi(args["--ttl"].(string))
42 | 	if err != nil {
43 | 		log.Fatalf("error parsing --ttl: %s", err)
44 | 	}
45 | 
46 | 	client := ec2.New(&aws.Config{
47 | 		Credentials: credentials.NewEnvCredentials(),
48 | 		Region:      args["--region"].(string),
49 | 	})
50 | 
51 | 	res, err := client.DescribeInstances(&ec2.DescribeInstancesInput{
52 | 		Filters: []*ec2.Filter{
53 | 			&ec2.Filter{
54 | 				Name: aws.String("tag:Name"),
55 | 				Values: []*string{
56 | 					aws.String(question.Name),
57 | 				},
58 | 			},
59 | 		},
60 | 	})
61 | 
62 | 	if err != nil {
63 | 		log.Fatalf("error: %s", err)
64 | 	}
65 | 
66 | 	if len(res.Reservations) == 0 {
67 | 		log.Fatalf("error: failed to find a matching host")
68 | 	}
69 | 
70 | 	if len(res.Reservations[0].Instances) == 0 {
71 | 		log.Fatalf("error: failed to find a matching host")
72 | 	}
73 | 
74 | 	ip := res.Reservations[0].Instances[0].PrivateIPAddress
75 | 
76 | 	answer := sdns.Answers{
77 | 		&sdns.Answer{
78 | 			Type:  "A",
79 | 			Value: *ip,
80 | 			TTL:   uint32(ttl),
81 | 		},
82 | 	}
83 | 
84 | 	sdns.Write(answer, os.Stdout)
85 | }
86 | 


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