Class: Delayed::SshRemoteWorker

Inherits:
Object
  • Object
show all
Defined in:
lib/delayed/ssh_remote_worker.rb,
lib/delayed/ssh_remote_worker/railtie.rb

Defined Under Namespace

Classes: Railtie

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(config) ⇒ SshRemoteWorker

Returns a new instance of SshRemoteWorker.



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# File 'lib/delayed/ssh_remote_worker.rb', line 16

def initialize(config)
  @config              = Hash[config.map { |k, v| [ k.to_sym, v ] }]
  @debug               = !!@config[:ssh_debug]

  @remote_ssh_username = @config[:ssh_username]
  @remote_ssh_hostname = @config[:ssh_hostname]
  @remote_ssh_port     = @config[:ssh_port].to_i
  @remote_ssh_port     = 22 if remote_ssh_port <= 0

  @remote_db_hostname  = @config[:host].to_s.strip
  @remote_db_hostname  = "localhost" if remote_db_hostname == ""
  @remote_db_port      = @config[:port].to_i
  @remote_db_port      = default_port_number(@config[:adapter]) if remote_db_port <= 0

  @local_db_hostname = "127.0.0.1"
  @local_db_port     = nil
end

Instance Attribute Details

#child ⇒ Object (readonly)

Returns the value of attribute child.



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# File 'lib/delayed/ssh_remote_worker.rb', line 13

def child
  @child
end

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/delayed/ssh_remote_worker.rb', line 14

def config
  @config
end

#gateway_in_rd ⇒ Object (readonly)

Returns the value of attribute gateway_in_rd.



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# File 'lib/delayed/ssh_remote_worker.rb', line 11

def gateway_in_rd
  @gateway_in_rd
end

#gateway_in_wr ⇒ Object (readonly)

Returns the value of attribute gateway_in_wr.



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# File 'lib/delayed/ssh_remote_worker.rb', line 11

def gateway_in_wr
  @gateway_in_wr
end

#gateway_out_rd ⇒ Object (readonly)

Returns the value of attribute gateway_out_rd.



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# File 'lib/delayed/ssh_remote_worker.rb', line 12

def gateway_out_rd
  @gateway_out_rd
end

#gateway_out_wr ⇒ Object (readonly)

Returns the value of attribute gateway_out_wr.



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# File 'lib/delayed/ssh_remote_worker.rb', line 12

def gateway_out_wr
  @gateway_out_wr
end

#gateway_port ⇒ Object (readonly)

Returns the value of attribute gateway_port.



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# File 'lib/delayed/ssh_remote_worker.rb', line 10

def gateway_port
  @gateway_port
end

#gateway_ssh ⇒ Object (readonly)

Returns the value of attribute gateway_ssh.



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# File 'lib/delayed/ssh_remote_worker.rb', line 10

def gateway_ssh
  @gateway_ssh
end

#local_db_hostname ⇒ Object (readonly)

Returns the value of attribute local_db_hostname.



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# File 'lib/delayed/ssh_remote_worker.rb', line 9

def local_db_hostname
  @local_db_hostname
end

#local_db_port ⇒ Object (readonly)

Returns the value of attribute local_db_port.



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# File 'lib/delayed/ssh_remote_worker.rb', line 9

def local_db_port
  @local_db_port
end

#remote_db_hostname ⇒ Object (readonly)

Returns the value of attribute remote_db_hostname.



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# File 'lib/delayed/ssh_remote_worker.rb', line 8

def remote_db_hostname
  @remote_db_hostname
end

#remote_db_port ⇒ Object (readonly)

Returns the value of attribute remote_db_port.



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# File 'lib/delayed/ssh_remote_worker.rb', line 8

def remote_db_port
  @remote_db_port
end

#remote_ssh_hostname ⇒ Object (readonly)

Returns the value of attribute remote_ssh_hostname.



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# File 'lib/delayed/ssh_remote_worker.rb', line 7

def remote_ssh_hostname
  @remote_ssh_hostname
end

#remote_ssh_port ⇒ Object (readonly)

Returns the value of attribute remote_ssh_port.



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# File 'lib/delayed/ssh_remote_worker.rb', line 7

def remote_ssh_port
  @remote_ssh_port
end

#remote_ssh_username ⇒ Object (readonly)

Returns the value of attribute remote_ssh_username.



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# File 'lib/delayed/ssh_remote_worker.rb', line 7

def remote_ssh_username
  @remote_ssh_username
end

Instance Method Details

#connect_to_tunneled_database ⇒ Object 



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# File 'lib/delayed/ssh_remote_worker.rb', line 75

def connect_to_tunneled_database
  # Load just ActiveRecord. Do this before any part of the native Rails project is loaded.
  require "active_record"

  # Connect to the remote Postgres database.
  ActiveRecord::Base.establish_connection(activerecord_config)

  # Log a simple query just to verify that we actually have a connection.
  debug "Connected to remote Postgres. Found #{ User.count } users in the remote database."
end

#create_port_tunnel ⇒ Object 



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# File 'lib/delayed/ssh_remote_worker.rb', line 34

def create_port_tunnel
  # Create two pipes - one will be used to get the port number from the child
  # process, the other will be used to tell the child process when it's time
  # to exit.
  ( @gateway_in_rd  , @gateway_in_wr  ) = IO.pipe
  ( @gateway_out_rd , @gateway_out_wr ) = IO.pipe

  # The child process will establish the SSH connection to the database server.
  @child = fork {
    debug "CHILD: Tunneling to #{ remote_db_hostname }:#{ remote_db_port } on #{ remote_ssh_username }@#{ remote_ssh_hostname }:#{ remote_ssh_port }."

    @gateway_ssh  = Net::SSH::Gateway.new(remote_ssh_hostname, remote_ssh_username, port: remote_ssh_port)
    @gateway_port = gateway_ssh.open(remote_db_hostname, remote_db_port)

    debug "CHILD: Notifying parent process of gateway port number #{ gateway_port }."

    gateway_out_rd.close
    gateway_out_wr.write(gateway_port.to_s)
    gateway_out_wr.close

    debug "CHILD: Waiting for parent to close pipe."

    gateway_in_wr.close
    gateway_in_rd.read
    gateway_in_rd.close

    debug "CHILD: Parent closed pipe. Exiting."

    gateway_ssh.shutdown!
  }

  # Get the port number back from the child process once the SSH connection is established.
  debug "PARENT: Reading port number from child."
  gateway_out_wr.close
  @local_db_port = Integer(gateway_out_rd.read)
  gateway_out_rd.close

  # Log and proceed with the next task.
  debug "PARENT: Received port number #{ gateway_port } from child. Proceeding with execution."
end

#destroy_port_tunnel ⇒ Object 



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# File 'lib/delayed/ssh_remote_worker.rb', line 86

def destroy_port_tunnel
  # Close the pipe with the gateway, indicating that it should close.
  debug "PARENT: Closing pipe with child to terminate gateway."
  gateway_in_wr.close
  gateway_in_rd.close
  Process.wait(child)
end