A sample recipe to install my erlang tarballs with the maximum amount of idempotence

README.md

Notes

While I call s3_file and use my databag_decrypt helpers, you can point to the downloads in my github repo here: https://github.com/lusis/erlang-and-centos/

The sha256 is in the filename so the checksum operator should work.

This is about as idempotent as I can get the cookbook. I've tested multiple scenarios:

• missing symlink
• missing installed product
• from scratch with neither symlink or installed product
• missing bin files

It uses erl +V to determine if the actual installed product is the one from the tarball.

default_attributes.rb

default[:va_erlang][:version] = "R13B04"
# Output of erl +V
default[:va_erlang][:vm_ver] = "5.7.5"
default[:va_erlang][:i386][:checksum] = "8f2746a44a10395ba22998ca7ce4376d39f538b434bd7f3da6c2aaeacba7a5dc"
default[:va_erlang][:x86_64][:checksum] = "06aa746ebd26073de5e52fbe1c0b1ad759571f4f6f6540860d646d82ee7c6e5a"
default[:va_erlang][:do_profile] = true
default[:va_erlang][:do_symlink] = true
default[:va_erlang][:install_dir] = "/opt/erlang-#{node[:va_erlang][:version]}"
default[:va_erlang][:run_dir] = "/opt/erlang"

erlang.sh.erb

if [ -d "<%= node[:va_erlang][:run_dir] %>/bin" ];then
  ERLANG_HOME=<%= node[:va_erlang][:run_dir] %>
  PATH=$ERLANG_HOME/bin:$PATH
  export ERLANG_HOME
  export PATH
fi

erlang_tarball_recipe.rb

include_recipe "s3client::default"

include_recipe "databag_decrypt::default"

s3_access_key = item_decrypt(search(:passwords, "id:s3_access_key").first[:data])
s3_secret_key = item_decrypt(search(:passwords, "id:s3_secret_key").first[:data])

case node.kernel.machine
when 'i686'
  erl_arch = 'i386'
when 'x86_64'
  erl_arch = 'x86_64'
else
  Chef::Log.error("I don't understand your arch yet: #{node.kernel.machine}")
end

erl_checksum = node[:va_erlang][erl_arch.to_sym][:checksum]
# PITA to continually type out
erlang_file_name = "erlang-#{node[:va_erlang][:version]}-#{erl_arch}-bin-#{erl_checksum}.tar.gz"
erlang_tar_gz = File.join(Chef::Config[:file_cache_path], "/", erlang_file_name)

s3_file erlang_tar_gz do
  bucket "our-packages"
  object_name erlang_file_name
  aws_access_key_id s3_access_key
  aws_secret_access_key s3_secret_key
  checksum erl_checksum
end

bash "install erlang #{node[:va_erlang][:version]}" do
  cwd Chef::Config[:file_cache_path]
  code <<-EOH
    mkdir #{node[:va_erlang][:install_dir]}
    tar -C #{node[:va_erlang][:install_dir]} -zxf #{erlang_tar_gz}
  EOH
  not_if "#{node[:va_erlang][:install_dir]}/erlang/bin/erl +V 2>&1 | awk '{ print $6 }' | grep '#{node[:va_erlang][:vm_ver]}' > /dev/null"
end

if node[:va_erlang][:do_symlink] == true and File.directory?("#{node[:va_erlang][:install_dir]}/erlang") then
    link node[:va_erlang][:run_dir] do
      to "#{node[:va_erlang][:install_dir]}/erlang"
    end
end

if node[:va_erlang][:do_profile] == true then
  template "/etc/profile.d/erlang.sh" do
    source "erlang.sh.erb"
    mode 0755
    owner "root"
    group "root"
  end
end