Format of File for drbqs-execute

Outline

drbqs-execute evaluates files in the context of an object of DRbQS::ProcessDefinition::Register. Therefore, we can use methods of DRbQS::ProcessDefinition::Register in files given to drbqs-execute.

drbqs-execute execute a server of which uri is made from hostname and port. Moreover, drbqs-execute make nodes connecting to the uri of server. The server and nodes can be over SSH.

Example

execute.rb

#!/usr/bin/env drbqs-execute
# -*-ruby-*-

usage message: "Message of this file", server: File.join(File.dirname(__FILE__), 'server.rb')

default server: :server1, port: 12345, node: [:node1, :node3, :node5], log: "/tmp/drbqs/log"

ssh_directory = "/ssh/path/to"

server :server1, 'example.com' do |server, ssh|
  ssh.directory ssh_directory
  ssh.output "/path/to/log"
  ssh.nice 5
  server.load "server.rb"
  server.log_level 'error'
end

server :local, 'localhost' do |server|
  server.load "server.rb"
  server.log_level 'error'
end

node :node_base, template: true do |node, ssh|
  ssh.directory ssh_directory
  ssh.output "/path/to/node_ssh"
  ssh.nice 10
  node.process 2
  node.load "server.rb"
  node.log_level 'error'
end

ssh_user = 'user_name'
[1, 2, 3, 4, 5, 6].each do |n|
  name = "node%02d" % n
  node name, load: :node_base do |node, ssh|
    ssh.connect "#{ssh_user}@#{name}.example.com"
  end
end

node :even, group: [:node02, :node04, :node06]
node :odd, group: [:node01, :node03, :node05]

Execution

In the above example, there is the shebang line

#!/usr/bin/env drbqs-execute

and therefore we can execute by

./execute.rb

If there is no shebang line, we type

drbqs-execute execute.rb

Help message

If we run the following command

drbqs-execute -h execute.rb

then help message of server.rb is displayed in addition to that of drbqs-execute.

Information of server and nodes

The command

drbqs-execute -i

shows information of server and nodes. The output is

Server:
 * server1    ssh
   local      local
Node:
 - node_base  ssh,template
   node01     ssh
   node02     ssh
   node03     ssh
   node04     ssh
   node05     ssh
   node06     ssh
 - even       group: node02,node04,node06
 - odd        group: node01,node03,node05
Port: 12345

The character "*" means default and "-" means virtual nodes (template or group).

Methods

The following methods are available.

server

"server" method corresponds to commands "drbqs-server" and "drbqs-ssh server". This method takes two arguments (server name and hostname), options set by hash and a block. If the block takes only one argument then the server is on localhost. If there are two block arguments then the server is executed over SSH. The first argument of block has methods similar to the options of command "drbqs-server". The second argument has methods similar to the options of command "drbqs-ssh". We can set the settings of servers by these methods.

See DRbQS::ProcessDefinition::Register#server

node

"node" method corresponds to commands "drbqs-node" and "drbqs-ssh node", which takes node name and options set by hash as arguments. As the same way of method "server" we can define nodes by method "node" The block taking one argument defines a node on localhost and the block taking two arguments defines a node over SSH. The first argument has methods similar to the options of command "drbqs-node" and the second argument has methods similar to the options of command "drbqs-ssh".

See DRbQS::ProcessDefinition::Register#node

clear_server

See DRbQS::ProcessDefinition::Register#clear_server

clear_node

See DRbQS::ProcessDefinition::Register#clear_node

default

We can set default server, default nodes, default port number of server by method "default".