Class: Aspera::Ssh

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

Overview

A simple wrapper around Net::SSH executes one command and get its result from stdout

Defined Under Namespace

Classes: Error

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(host, username, ssh_options) ⇒ Ssh

ssh_options: same as Net::SSH.start see: net-ssh.github.io/net-ssh/classes/Net/SSH.html#method-c-start



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# File 'lib/aspera/ssh.rb', line 37

def initialize(host, username, ssh_options)
  Aspera.assert_type(host, String)
  Aspera.assert_type(username, String)
  Aspera.assert_type(ssh_options, Hash)
  @host = host
  @username = username
  @ssh_options = ssh_options.dup
  @ssh_options[:logger] = Log.log unless @ssh_options.key?(:logger)
  @ssh_options[:verbose] = :warn unless @ssh_options.key?(:verbose)
  @ssh_options[:use_agent] = false unless @ssh_options.key?(:use_agent)
  Log.log.debug{"ssh:#{@username}@#{@host}"}
  Log.dump(:ssh_options, @ssh_options)
end

Class Method Details

.disable_ecd_sha2_algorithms ⇒ Object

HACK: disable some algorithms



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# File 'lib/aspera/ssh.rb', line 29

def disable_ecd_sha2_algorithms
  Log.log.debug('Disabling SSH ecdsa')
  Net::SSH::Transport::Algorithms::ALGORITHMS.each_value{ |a| a.reject!{ |a| a =~ /^ecd(sa|h)-sha2/}}
  Net::SSH::KnownHosts::SUPPORTED_TYPE.reject!{ |t| t =~ /^ecd(sa|h)-sha2/}
end

.disable_ed25519_keys ⇒ Object

HACK: disable some key type



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# File 'lib/aspera/ssh.rb', line 15

def disable_ed25519_keys
  Log.log.debug('Disabling SSH ed25519 user keys')
  old_verbose = $VERBOSE
  $VERBOSE = nil
  Net::SSH::Authentication::Session.class_eval do
    define_method(:default_keys) do
      %w[.ssh .ssh2].product(%w[rsa dsa ecdsa]).map{"~/#{_1}/id_#{_2}"}.freeze
    end
    private(:default_keys)
  end rescue nil
  $VERBOSE = old_verbose
end

Instance Method Details

#execute(cmd, input: nil, exception: false) ⇒ Object

Anything on stderr raises an exception



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# File 'lib/aspera/ssh.rb', line 52

def execute(cmd, input: nil, exception: false)
  Aspera.assert_type(cmd, String)
  Log.log.debug{"cmd=#{cmd}"}
  response = []
  error = []
  Net::SSH.start(@host, @username, @ssh_options) do |session|
    ssh_channel = session.open_channel do |channel|
      # prepare stdout processing
      channel.on_data{ |_chan, data| response.push(data)}
      # prepare stderr processing, stderr if type = 1
      channel.on_extended_data do |_chan, _type, data|
        error.push(data)
      end
      channel.on_request('exit-status') do |_ch, data|
        exit_code = data.read_long
        next if exit_code.zero?
        error_message = "#{cmd}: exit #{exit_code}, #{error.join.chomp}"
        raise Error, error_message if exception
        # Happens when windows user hasn't logged in and created home account.
        error_message += "\nHint: home not created in Windows?" if data.include?('Could not chdir to home directory')
        Log.log.debug(error_message)
      end
      # send command to SSH channel (execute) cspell: disable-next-line
      channel.send('cexe'.reverse, cmd){ |_ch, _success| channel.send_data(input) unless input.nil?}
    end
    # wait for channel to finish (command exit)
    ssh_channel.wait
    # main SSH session loop
    session.loop
  end
  # response as single string
  return response.join
end