Class: Weave::ConnectionPool

Inherits:
Object
  • Object
show all
Defined in:
lib/weave.rb

Overview

A pool of SSH connections. Operations over the pool may be performed in serial or in parallel.

Instance Method Summary collapse

Constructor Details

#initialize(host_list = []) ⇒ ConnectionPool

use #execute_with (instead of #execute) to specify the whole list of hosts each time.

Parameters:

  • host_list (Array) (defaults to: []) —

    the array of hosts, of the form user@host. You may leave off this argument, and



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# File 'lib/weave.rb', line 63

def initialize(host_list = [])
  @hosts = host_list
  @connections = host_list.reduce({}) { |pool, host| pool.merge(host => LazyConnection.new(host)) }
end

Instance Method Details

#disconnect! ⇒ Object

Disconnect all open connections.



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# File 'lib/weave.rb', line 105

def disconnect!() @connections.each_value(&:disconnect) end

#execute(options = {}, &block) ⇒ Object

Run a command over the connection pool. The block is evaluated in the context of LazyConnection.

Parameters:

  • options (Hash) (defaults to: {}) —

    the various knobs

Options Hash (options):

  • :args (Array) —

    the arguments to pass through to the block when it runs.

  • :num_threads (Fixnum or Symbol) —

    the number of concurrent threads to use to process this command, or :unlimited to use a thread for every host. Defaults to DEFAULT_THREAD_POOL_SIZE.

  • :serial (Boolean) —

    whether to process the command for each connection one at a time.

  • :batch_by (Fixnum) —

    if set, group the connections into batches of no more than this value and fully process each batch before starting the next one.



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# File 'lib/weave.rb', line 77

def execute(options = {}, &block)
  execute_with(@hosts, options, &block)
end

#execute_with(host_list, options = {}, &block) ⇒ Object

This is the same as #execute, except that host_list overrides the list of connections with which this ConnectionPool was initialized. Any hosts in here that weren't already in the pool will be added.



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# File 'lib/weave.rb', line 83

def execute_with(host_list, options = {}, &block)
  host_list.each { |host| @connections[host] ||= LazyConnection.new(host) }
  args = options[:args] || []
  num_threads = options[:num_threads] || DEFAULT_THREAD_POOL_SIZE
  if options[:serial]
    host_list.each { |host| @connections[host].self_eval args, &block }
  elsif options[:batch_by]
    num_threads = options[:batch_by] if num_threads == :unlimited
    host_list.each_slice(options[:batch_by]) do |batch|
      Weave.with_thread_pool(batch, num_threads) do |host, mutex|
        @connections[host].self_eval args, mutex, &block
      end
    end
  else
    num_threads = host_list.size if num_threads == :unlimited
    Weave.with_thread_pool(host_list, num_threads) do |host, mutex|
      @connections[host].self_eval args, mutex, &block
    end
  end
end