Class: RemoteSystem

Inherits:
System show all
Defined in:
lib/remote_system.rb

Overview

Copyright © 2013-2016 SUSE LLC

This program is free software; you can redistribute it and/or modify it under the terms of version 3 of the GNU General Public License as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, contact SUSE LLC.

To contact SUSE about this file by physical or electronic mail, you may find current contact information at www.suse.com

Instance Attribute Summary collapse

Attributes inherited from System

#locale

Instance Method Summary collapse

Methods inherited from System

#arch, #check_create_archive_dependencies, #check_requirement, #check_retrieve_files_dependencies, #create_archive, for, #has_command?, #managed_files_database, #run_command_with_progress, #run_script, #run_script_with_progress

Constructor Details

#initialize(host, opts = {}) ⇒ RemoteSystem

Returns a new instance of RemoteSystem.



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# File 'lib/remote_system.rb', line 25

def initialize(host, opts = {})
  options = {
    remote_user: "root",
    ssh_port: nil,
    ssh_identity_file: nil
  }.merge(opts)

  @host = host
  @remote_user = options[:remote_user]
  @ssh_port = options[:ssh_port]
  @ssh_identity_file = options[:ssh_identity_file]

  connect
end

Instance Attribute Details

#host ⇒ Object (readonly)

Returns the value of attribute host.



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# File 'lib/remote_system.rb', line 19

def host
  @host
end

#remote_user ⇒ Object (readonly)

Returns the value of attribute remote_user.



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# File 'lib/remote_system.rb', line 19

def remote_user
  @remote_user
end

#ssh_identity_file ⇒ Object (readonly)

Returns the value of attribute ssh_identity_file.



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# File 'lib/remote_system.rb', line 19

def ssh_identity_file
  @ssh_identity_file
end

#ssh_port ⇒ Object (readonly)

Returns the value of attribute ssh_port.



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# File 'lib/remote_system.rb', line 19

def ssh_port
  @ssh_port
end

Instance Method Details

#connect ⇒ Object

Tries to run the noop-command(:) on the remote system as root (without a password or passphrase) and raises an Machinery::Errors::SshConnectionFailed exception when it’s not successful.



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# File 'lib/remote_system.rb', line 103

def connect
  LoggedCheetah.run(*build_command(:ssh), "-q", "-o", "BatchMode=yes",
    "#{remote_user}@#{host}", ":")
rescue Cheetah::ExecutionFailed
  raise Machinery::Errors::SshConnectionFailed.new(
    "Could not establish SSH connection to host '#{host}'. Please make sure that " \
    "you can connect non-interactively as #{remote_user}, e.g. using ssh-agent.\n\n" \
    "To copy your default ssh key to the machine run:\n" \
    "ssh-copy-id #{remote_user}@#{host}"
  )
end

#inject_file(source, destination) ⇒ Object

Copies a file to the system



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# File 'lib/remote_system.rb', line 161

def inject_file(source, destination)
  destination = "#{remote_user}@#{host}:#{destination}"

  cmd = [
    *build_command(:scp),
    source,
    destination
  ]

  begin
    LoggedCheetah.run(*cmd)
  rescue Cheetah::ExecutionFailed => e
    raise Machinery::Errors::InjectFileFailed.new(
      "Could not inject file '#{source}' to host '#{host}'.\nError: #{e}"
    )
  end
end

#read_file(file) ⇒ Object

Reads a file from the System. Returns nil if it does not exist.



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# File 'lib/remote_system.rb', line 149

def read_file(file)
  run_command("cat", file, stdout: :capture, privileged: true)
rescue Cheetah::ExecutionFailed => e
  if e.status.exitstatus == 1
    # File not found, return nil
    return
  else
    raise
  end
end

#remove_file(file) ⇒ Object

Removes a file from the system



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# File 'lib/remote_system.rb', line 180

def remove_file(file)
  run_command("rm", file)
rescue Cheetah::ExecutionFailed => e
  raise Machinery::Errors::RemoveFileFailed.new(
    "Could not remove file '#{file}' on host '#{host}'.\nError: #{e}"
  )
end

#requires_root? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/remote_system.rb', line 40

def requires_root?
  false
end

#retrieve_files(filelist, destination) ⇒ Object

Retrieves files specified in filelist from the remote system and raises an Machinery::Errors::RsyncFailed exception when it’s not successful. Destination is the directory where to put the files.



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# File 'lib/remote_system.rb', line 119

def retrieve_files(filelist, destination)
  source = "#{remote_user}@#{host}:/"
  if remote_user != "root"
    rsync_path = "sudo -n rsync"
  else
    rsync_path = "rsync"
  end

  cmd = [
    "rsync",
    "-e", build_command(:ssh).join(" "),
    "--chmod=go-rwx",
    "--files-from=-",
    "--rsync-path=#{rsync_path}",
    source,
    destination,
    stdout: :capture,
    stdin: filelist.join("\n")
  ]
  begin
    LoggedCheetah.run(*cmd)
  rescue Cheetah::ExecutionFailed  => e
    raise Machinery::Errors::RsyncFailed.new(
    "Could not rsync files from host '#{host}'.\n" \
    "Error: #{e}"
  )
  end
end

#run_command(*args) ⇒ Object 



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# File 'lib/remote_system.rb', line 44

def run_command(*args)
  options = args.last.is_a?(Hash) ? args.pop : {}

  # There are three valid ways how to call Cheetah.run, whose interface this
  # method mimics. The following code ensures that the "commands" variable
  # consistently (in all three cases) contains an array of arrays specifying
  # commands and their arguments.
  #
  # See comment in Cheetah.build_commands for more detailed explanation:
  #
  #   https://github.com/openSUSE/cheetah/blob/0cd3f88c1210305e87dfc4852bb83040e82d783f/lib/cheetah.rb#L395
  #
  commands = args.all? { |a| a.is_a?(Array) } ? args : [args]

  # When ssh executes commands, it passes them through shell expansion. For
  # example, compare
  #
  #   $ echo '$HOME'
  #   $HOME
  #
  # with
  #
  #   $ ssh localhost echo '$HOME'
  #   /home/dmajda
  #
  # To mitigate that and maintain usual Cheetah semantics, we need to protect
  # the command and its arguments using another layer of escaping.
  escaped_commands = commands.map do |command|
    command.map { |c| Shellwords.escape(c) }
  end

  # Arrange the commands in a way that allows piped commands trough ssh.
  piped_args = escaped_commands[0..-2].flat_map do |command|
    [*command, "|"]
  end + escaped_commands.last

  if options[:disable_logging]
    cheetah_class = Cheetah
  else
    cheetah_class = LoggedCheetah
  end

  sudo = ["sudo", "-n"] if options[:privileged] && remote_user != "root"
  cmds = [
    *build_command(:ssh), "#{remote_user}@#{host}", "-o", \
    "LogLevel=ERROR", sudo, "LANGUAGE=", "LC_ALL=#{locale}", *piped_args, options
  ].compact.flatten

  cheetah_class.run(*cmds)
rescue Cheetah::ExecutionFailed => e
  if e.stderr && e.stderr.include?("password is required")
    raise Machinery::Errors::InsufficientPrivileges.new(remote_user, host)
  else
    raise e
  end
end

#type ⇒ Object 



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# File 'lib/remote_system.rb', line 21

def type
  "remote"
end