Class: Train::Transports::SSH::Connection

Inherits:
BaseConnection
  • Object
show all
Defined in:
lib/train/transports/ssh_connection.rb

Overview

A Connection instance can be generated and re-generated, given new connection details such as connection port, hostname, credentials, etc. This object is responsible for carrying out the actions on the remote host such as executing commands, transferring files, etc.

Author:

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Connection

Returns a new instance of Connection.



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# File 'lib/train/transports/ssh_connection.rb', line 34

def initialize(options)
  # Track IOS command retries to prevent infinite loop on IOError. This must
  # be done before `super()` because the parent runs detection commands.
  @ios_cmd_retries = 0
  super(options)
  @username               = @options.delete(:username)
  @hostname               = @options.delete(:hostname)
  @port                   = @options[:port] # don't delete from options
  @connection_retries     = @options.delete(:connection_retries)
  @connection_retry_sleep = @options.delete(:connection_retry_sleep)
  @max_wait_until_ready   = @options.delete(:max_wait_until_ready)
  @max_ssh_sessions       = @options.delete(:max_ssh_connections) { 9 }
  @session                = nil
  @transport_options      = @options.delete(:transport_options)
  @cmd_wrapper            = nil
  @proxy_command          = @options.delete(:proxy_command)
  @bastion_host           = @options.delete(:bastion_host)
  @bastion_user           = @options.delete(:bastion_user)
  @bastion_port           = @options.delete(:bastion_port)
  @cmd_wrapper            = CommandWrapper.load(self, @transport_options)
end

Instance Attribute Details

#hostname ⇒ Object (readonly)

rubocop:disable Metrics/ClassLength



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# File 'lib/train/transports/ssh_connection.rb', line 33

def hostname
  @hostname
end

Instance Method Details

#check_proxy ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 81

def check_proxy
  [@proxy_command, @bastion_host].any? { |type| !type.nil? }
end

#close ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 57

def close
  return if @session.nil?
  logger.debug("[SSH] closing connection to #{self}")
  session.close
ensure
  @session = nil
end

#download(remotes, local) ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 120

def download(remotes, local)
  waits = []
  Array(remotes).map do |remote|
    opts = file(remote).directory? ? { recursive: true } : {}
    waits.push session.scp.download(remote, local, opts) do |_ch, name, recv, total|
      logger.debug("Downloaded #{name} (#{total} bytes)") if recv == total
    end
    waits.shift.wait while waits.length >= @max_ssh_sessions
  end
  waits.each(&:wait)
rescue Net::SSH::Exception => ex
  raise Train::Transports::SSHFailed, "SCP download failed (#{ex.message})"
end

#generate_proxy_command ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 85

def generate_proxy_command
  return @proxy_command unless @proxy_command.nil?
  args = %w{ ssh }
  args += ssh_opts
  args += %W( #{@bastion_user}@#{@bastion_host} )
  args += %W( -p #{@bastion_port} )
  args += %w{ -W %h:%p }
  args.join(' ')
end

#login_command ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 96

def 
  args = ssh_opts
  args += %W( -o ProxyCommand='#{generate_proxy_command}' ) if check_proxy
  args += %W( -p #{@port} )
  args += %W( #{@username}@#{@hostname} )
  LoginCommand.new('ssh', args)
end

#ssh_opts ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 65

def ssh_opts
  level = logger.debug? ? 'VERBOSE' : 'ERROR'
  fwd_agent = options[:forward_agent] ? 'yes' : 'no'

  args  = %w{ -o UserKnownHostsFile=/dev/null }
  args += %w{ -o StrictHostKeyChecking=no }
  args += %w{ -o IdentitiesOnly=yes } if options[:keys]
  args += %w{ -o BatchMode=yes } if options[:non_interactive]
  args += %W( -o LogLevel=#{level} )
  args += %W( -o ForwardAgent=#{fwd_agent} ) if options.key?(:forward_agent)
  Array(options[:keys]).each do |ssh_key|
    args += %W( -i #{ssh_key} )
  end
  args
end

#upload(locals, remote) ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 105

def upload(locals, remote)
  waits = []
  Array(locals).each do |local|
    opts = File.directory?(local) ? { recursive: true } : {}

    waits.push session.scp.upload(local, remote, opts) do |_ch, name, sent, total|
      logger.debug("Uploaded #{name} (#{total} bytes)") if sent == total
    end
    waits.shift.wait while waits.length >= @max_ssh_sessions
  end
  waits.each(&:wait)
rescue Net::SSH::Exception => ex
  raise Train::Transports::SSHFailed, "SCP upload failed (#{ex.message})"
end

#uri ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 146

def uri
  "ssh://#{@username}@#{@hostname}:#{@port}"
end

#wait_until_ready ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 135

def wait_until_ready
  delay = 3
  session(
    retries: @max_wait_until_ready / delay,
    delay:   delay,
    message: "Waiting for SSH service on #{@hostname}:#{@port}, " \
             "retrying in #{delay} seconds",
  )
  run_command(PING_COMMAND.dup)
end