Running a command via Rendezvous and capturing the output.

README.md

This example captures the output of running a command and then prints that output to STDOUT along with an execution summary.

Usage

bundle install --path .bundle
./example.rb [APP] [COMMAND]

example.rb

#!/usr/bin/env ruby

require 'bundler/setup'
require 'rendezvous'
require 'heroku-api'
require 'netrc'
require 'benchmark'

if ARGV.size < 2
  puts "Usage: example.rb APP COMMAND"
  exit
end

_, api_key = Netrc.read['api.heroku.com']
heroku = Heroku::API.new(api_key: api_key)

data = heroku.post_ps(
  ARGV[0],
  ARGV[1..-1].join(' '),
  attach: true,
  ps_env: {}
).body

in_rd, in_wr = IO.pipe
out_rd, out_wr = IO.pipe

in_wr.sync = true
in_wr.write(4.chr) # EOF
in_wr.flush

output = ""

thread = Thread.new do
  begin
    loop do
      output << out_rd.readpartial(10000)
    end
  rescue EOFError
  end
end


time = Benchmark.realtime do
  Rendezvous.start(
    url: data['rendezvous_url'],
    input: in_rd,
    output: out_wr
  )
end

# send the thread an EOF and wait for it to complete
out_wr.close
thread.join

puts "-" * 40
puts "App: #{ARGV[0]}"
puts "Command: #{ARGV[1..-1].join(' ')}"
puts "Execution time: #{time}"
puts "-" * 40
puts "Output"
puts "-" * 40
puts output
puts "-" * 40

Gemfile

source 'https://rubygems.org/'

gem 'rendezvous'
gem 'heroku-api'
gem 'netrc'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    excon (0.25.0)
    heroku-api (0.3.13)
      excon (~> 0.25.0)
    netrc (0.7.7)
    rendezvous (0.0.2)

PLATFORMS
  ruby

DEPENDENCIES
  heroku-api
  netrc
  rendezvous