EC2 の一覧を取得する Golang Sample スクリプト

oreno-ec2.go

package main

import (
    "os"
    "os/exec"
    "fmt"
    "flag"
    "strings"
    "io/ioutil"

    "github.com/aws/aws-sdk-go/aws"
    "github.com/aws/aws-sdk-go/aws/session"
    "github.com/aws/aws-sdk-go/aws/credentials"
    "github.com/aws/aws-sdk-go/service/ec2"

    "github.com/olekukonko/tablewriter"
)

var (
    argProfile = flag.String("profile", "", "AWS Shared Credential の Profile 名を指定する")
    argRegion = flag.String("region", "ap-northeast-1", "AWS Region 名を指定する")
    argDnsMasq = flag.Bool("dnsmasq", false, "dnsmasq 用の hosts リストを生成する")
    argComma = flag.Bool("comma", false, "カンマ区切りの hosts リストを生成する")
    argMarkDown = flag.Bool("markdown", false, "Markdown のテーブルフォーマットで出力する")
    argRead = flag.Bool("read", false, "-path オプションで指定したファイルを読み取る")
    argFilePath = flag.String("path", "hosts_list", "ファイルのパスを指定する")
    argCommand = flag.String("command", "", "指定したコマンドを実行する")
)

func output_tbl(data [][]string) {
    table := tablewriter.NewWriter(os.Stdout)
    table.SetHeader([]string{"tag:Name", "InstanceId", "InstanceType", "AZ", "PrivateIp", "PublicIp", "Status"})

    for _, value := range data {
        table.Append(value)
    }
    table.Render()
}

func output_markdown(data [][]string) {
    table := tablewriter.NewWriter(os.Stdout)
    table.SetHeader([]string{"tag:Name", "InstanceId", "InstanceType", "AZ", "PrivateIp", "PublicIp", "Status"})
    table.SetBorders(tablewriter.Border{Left: true, Top: false, Right: true, Bottom: false})
    table.SetCenterSeparator("|")

    for _, value := range data {
        table.Append(value)
    }
    table.Render()
}

func output_dnsmasq(data [][]string, file_path string) {
    var tag_name string
    hosts_list := []string{}
    for _, value := range data {
        if value[0] == "" {
            tag_name = "TagName_Not_Assigned_" + value[4]
        } else {
            tag_name = value[0]
        }
        line := []string{
            "address=",
            tag_name,
            value[4],
        }
        host_list := strings.Join(line, "/")
        hosts_list = append(hosts_list, host_list)
    }

    write_hosts_list_file(hosts_list, file_path)

}

func output_comma(data [][]string, file_path string) {
    hosts_list := []string{}
    for _, value := range data {
        host_list := strings.Join(value, ",")
        hosts_list = append(hosts_list, host_list)
    }

    write_hosts_list_file(hosts_list, file_path)

}

func read_hosts_list_file(file_path string) {
    contents, _ := ioutil.ReadFile(file_path)
    fmt.Println(string(contents))
}

func write_hosts_list_file(hosts_list []string, file_path string) {
    var contents string
    contents = strings.Join(hosts_list, "\n")
    err := ioutil.WriteFile(file_path, []byte(contents), 0644)
    if err != nil {
        panic(err)
        os.Exit(1)
    }
}

func exec_command(command string) {
    out, err := exec.Command("sh", "-c", command).Output()
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    fmt.Println(string(out))
}

func aws_ec2_client(profile string, region string) *ec2.EC2 {
    var config aws.Config
    if profile != "" {
        creds := credentials.NewSharedCredentials("", profile)
        config = aws.Config{Region: aws.String(region), Credentials: creds}
    } else {
        config = aws.Config{Region: aws.String(region)}
    }
    sess := session.New(&config)
    ec2_client := ec2.New(sess)
    return ec2_client
}

func main() {
    flag.Parse()

    if *argRead {
        if *argFilePath != "" {
            read_hosts_list_file(*argFilePath)
            os.Exit(0)
        } else {
            os.Exit(1)
        }
    }

    ec2_client := aws_ec2_client(*argProfile, *argRegion)
    res, err := ec2_client.DescribeInstances(nil)
    if err != nil {
        panic(err)
        os.Exit(1)
    }

    instances := [][]string{}
    for _, r := range res.Reservations {
        for _, i := range r.Instances {
            var tag_name string
            for _, t := range i.Tags {
                if *t.Key == "Name" {
                    tag_name = *t.Value
                }
            }
            if i.PublicIpAddress == nil {
                i.PublicIpAddress = aws.String("Not assignment")
            }
            instance := []string{
                tag_name,
                *i.InstanceId,
                *i.InstanceType,
                *i.Placement.AvailabilityZone,
                *i.PrivateIpAddress,
                *i.PublicIpAddress,
                *i.State.Name,
            }
            instances = append(instances, instance)
        }
    }
    if *argDnsMasq {
        output_dnsmasq(instances, *argFilePath)
        if *argCommand != "" {
            exec_command(*argCommand)
        }
    } else if *argComma {
        output_comma(instances, *argFilePath)
    } else if *argMarkDown {
        output_markdown(instances)
    } else {
        output_tbl(instances)
    }
}