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 36

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)

  @session                = nil
  @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 }
  @transport_options      = @options.delete(:transport_options)
  @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

#transport_options ⇒ Object (readonly)

Returns the value of attribute transport_options.



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

def transport_options
  @transport_options
end

Instance Method Details

#check_proxy ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 86

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 61

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 126

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

#forward_remote(port, host, remote_port, remote_host = "127.0.0.1") ⇒ Object

remote_port_forwarding



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# File 'lib/train/transports/ssh_connection.rb', line 157

def forward_remote(port, host, remote_port, remote_host = "127.0.0.1")
  @session.forward.remote(port, host, remote_port, remote_host)
end

#generate_proxy_command ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 90

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 102

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

#obscured_options ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 161

def obscured_options
  options_to_print = @options.clone
  options_to_print[:password] = "<hidden>" if options_to_print.key?(:password)
  options_to_print
end

#ssh_opts ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 70

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 111

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 152

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

#wait_until_ready ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 141

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