ec2-host

Search hosts on AWS EC2

Installation

gem install ec2-host

How it works

This gems uses tagging of EC2 resources. You can configure, but basically use Name tag for hostname (this is default of EC2) and Roles tag for roles.

You can manage roles of a host, and search hosts having a specified role using thease tags with this gem.

Configuration

You can write a configuration file located at /etc/sysconfig/ec2-host or /etc/default/ec2-host (You can configure this path by EC2_HOST_CONFIG_FILE environment variable), or as environment variables:

AWS SDK (CLI) parameters:

AWS_ACCESS_KEY_ID: AWS SDK (CLI) crendentials. Default loads a credentials file
AWS_SECRET_ACCESS_KEY: AWS SDK (CLI) credentials. Default load a credentials file
AWS_DEFAULT_REGION (AWS_REGION); AWS SDK (CLI) region such as ap-northeast-1, us-east-1. Default obtains from $HOME/.aws/config with profile AWS_DEFAULT_PROFILE.
AWS_DEFAULT_PROFILE (AWS_PROFILE): The profile key of the AWS SDK (CLI) credentails file. Default is default
AWS_CREDENTIAL_FILE (AWS_CREDENTIALS_FILE): Path of the AWS SDK (CLI) credentails file. Default is $HOME/.aws/credentials. See Configuring the AWS Command Line Interface for details.

ec2-host parameters:

HOSTNAME_TAG (optional): EC2 tag key used to express a hostname. The default is Name.
ROLES_TAG (optional): EC2 tag keys used to express roles. The default is Roles
You can assign multiple roles seperated by ARRAY_TAG_DELIMITER (default: ,)
Also, you can express levels of roles delimited by ROLE_TAG_DELIMITER (default :)
Example: admin:ami, then EC2::Host.new(role: 'admin:ami') and also EC2::Host.new(role1: 'admin') returns this host
ROLE_TAG_DELIMITER (optional): A delimiter to express levels of roles. Default is :
OPTIONAL_STRING_TAGS (optional): You may add optional non-array tags. You can specify multiple tags like Service,Status.
OPTIONAL_ARRAY_TAGS (optional): You may add optional array tags. Array tags allows multiple values delimited by ARRAY_TAG_DELIMITER (default: ,)
ARRAY_TAG_DELIMITER (optional): A delimiter to express array. Default is ,
ROLE_MAX_DEPTH (optional): The maximum depth of levels of roles. Default is 3.
LOG_LEVEL (optional): Log level such as info, debug, error. The default is info.

See example.conf

Tag Example

Name: hostname
Roles: app:web,app:db
Service: sugoi
Status: setup

CLI Usage

CLI Example

$ ec2-host -j
{"hostname":"test","roles":["admin:ami","test"],"region":"ap-northeast-1","instance_id":"i-85900780","private_ip_address":"172.31.23.50","public_ip_address":null,"launch_time":"2013-09-16 06:14:20 UTC","state":"running","monitoring":"disabled"}
{"hostname":"ip-172-31-6-194","roles":["isucon4:qual"],"region":"ap-northeast-1","instance_id":"i-f88cc8e1","private_ip_address":"172.31.6.194","public_ip_address":null,"launch_time":"2014-10-20 15:57:23 UTC","state":"running","monitoring":"disabled"}

$ ec2-host
test
ip-172-31-6-194 # if Name tag is not available

$ ec2-host --role1 admin
test

$ ec2-host --role admin:ami
test

$ ec2-host --pretty-json
[
  {
    "hostname": "test",
    "roles": [
      "admin:ami",
      "test"
    ],
    "region": "ap-northeast-1",
    "instance_id": "i-85900780",
    "private_ip_address": "172.31.23.50",
    "public_ip_address": null,
    "launch_time": "2013-09-16 06:14:20 UTC",
    "state": "running",
    "monitoring": "disabled"
  },
  {
    "hostname": "ip-172-31-6-194",
    "roles": [
      "isucon4:qual"
    ],
    "region": "ap-northeast-1",
    "instance_id": "i-f88cc8e1",
    "private_ip_address": "172.31.6.194",
    "public_ip_address": null,
    "launch_time": "2014-10-20 15:57:23 UTC",
    "state": "running",
    "monitoring": "disabled"
  }
]

CLI Help

$ bin/ec2-host --help
Usage: ec2-host [options]
        --hostname one,two,three     name or private_dns_name
    -r, --role one,two,three         role
        --r1, --role1 one,two,three  role1, 1th part of role delimited by :
        --r2, --role2 one,two,three  role2, 2th part of role delimited by :
        --r3, --role3 one,two,three  role3, 3th part of role delimited by :
        --instance-id one,two,three  instance_id
        --state one,two,three        filter with instance state (default: running)
        --monitoring one,two,three   filter with instance monitoring
    -a, --all                        list all hosts (remove default filter)
        --private-ip, --ip           show private ip address instead of hostname
        --public-ip                  show public ip address instead of hostname
    -i, --info                       show host info
    -j, --jsonl                      show host info in line delimited json
        --json                       show host info in json
        --pretty-json                show host info in pretty json
        --debug                      debug mode
    -h, --help                       show help

Library Usage

Library Example

require 'ec2-host'

hosts = EC2::Host.new(role: 'admin:ami')
hosts.each do |host|
  puts host
end

Library Reference

See sonots.github.io/ec2-host/frames.html.

ChangeLog

See CHANGELOG.md for details.

For Developers

ToDo

Support assume-roles
Use mock/stub to run test (currently, directly accessing to EC2)
Should cache a result of describe-instances in like 30 seconds?

How to Run test

NOTE: Currently, mock is not supported yet. So, you have to create your own AWS account, and instances.

Configure .env file as

AWS_ACCESS_KEY_ID=
AWS_SECRET_ACCESS_KEY=
AWS_DEFAULT_REGION=
EC2_HOST_CONFIG_FILE=.env
OPTIONAL_ARRAY_TAGS=Tags
OPTIONAL_STRING_TAGS=Service,Status

Install terraform and run to create instances for tests

$ brew install terraform
$ env $(cat .env) terraform plan
$ env $(cat .env) terraform apply

Run test

$ bundle exec rspec

After working, destory instances by commenting out terraform.tf and apply.

How to Release Gem

Update gem.version in the gemspec
Update CHANGELOG.md
git commit && git push
Run bundle exec rake release

How to Update doc

Run bundle exec yard
git commit && git push

Licenses

See LICENSE