slack に投稿する。https://api.slack.com/methods/chat.postMessage

slack-notify.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-
require 'uri'
require 'net/http'

message = ARGV.join(" ")

host = `hostname -s`

if message.empty?
  message = 'なにか終わったかも'
end

text = URI.escape(message)
token = ENV['SLACK_TOKEN']
channel = "#random"

params = {
 :text => message,
 :token => token,
 :channel => channel,
 :username => host,
}

uri = URI::HTTPS.build(:host => "slack.com", :path => "/api/chat.postMessage")
uri.query =  URI.encode_www_form(params)
Net::HTTP.get(uri)