Class: OsVm::Shell

Inherits:
Object
  • Object
show all
Defined in:
lib/osvm/shell.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(machine, index, socket_path, log_path, default_timeout:, name: nil) ⇒ Shell

Returns a new instance of Shell.

Parameters:

  • machine (Machine)
  • index (Integer)
  • name (String, nil) (defaults to: nil)
  • socket_path (String)
  • log_path (String)
  • default_timeout (Integer) 


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# File 'lib/osvm/shell.rb', line 25

def initialize(machine, index, socket_path, log_path, default_timeout:, name: nil)
  @machine = machine
  @index = index
  @name = name
  @socket_path = socket_path
  @default_timeout = default_timeout
  @log = ShellLog.new(log_path, shell_index: index, shell_name: name)
  @mutex = Mutex.new
  @up = false
  @server = nil
  @io = nil
end

Instance Attribute Details

#index ⇒ Integer (readonly)

Returns:

  • (Integer) 


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# File 'lib/osvm/shell.rb', line 11

def index
  @index
end

#io ⇒ Object (readonly, protected)

Returns the value of attribute io.



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# File 'lib/osvm/shell.rb', line 243

def io
  @io
end

#log ⇒ Object (readonly, protected)

Returns the value of attribute log.



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# File 'lib/osvm/shell.rb', line 243

def log
  @log
end

#machine ⇒ Machine (readonly)

Returns:



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# File 'lib/osvm/shell.rb', line 8

def machine
  @machine
end

#mutex ⇒ Object (readonly, protected)

Returns the value of attribute mutex.



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# File 'lib/osvm/shell.rb', line 243

def mutex
  @mutex
end

#name ⇒ String? (readonly)

Returns:

  • (String, nil) 


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# File 'lib/osvm/shell.rb', line 14

def name
  @name
end

#server ⇒ Object (readonly, protected)

Returns the value of attribute server.



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# File 'lib/osvm/shell.rb', line 243

def server
  @server
end

#socket_path ⇒ String (readonly)

Returns:

  • (String) 


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# File 'lib/osvm/shell.rb', line 17

def socket_path
  @socket_path
end

Instance Method Details

#accept(timeout: @default_timeout) ⇒ Object (protected) 



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# File 'lib/osvm/shell.rb', line 267

def accept(timeout: @default_timeout)
  raise "machine #{machine.name} is not running" unless machine.running?
  return io unless io.nil?

  t1 = Time.now

  loop do
    machine.raise_if_kernel_failed!

    if t1 + timeout < Time.now
      raise TimeoutError, 'Timeout occurred while waiting for shell connection'
    elsif !machine.running?
      raise Error, 'Machine is not running'
    end

    rs = server.wait_readable(1)
    next unless rs

    begin
      @io = server.accept_nonblock
      return io
    rescue IO::WaitReadable, Errno::EINTR
      next
    end
  end
end

#all_fail(*cmds) ⇒ Array<Array<[Integer, String]>>

Execute all commands and check that they all fail

Parameters:

  • cmds (String)

Returns:

  • (Array<Array<[Integer, String]>>) 


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# File 'lib/osvm/shell.rb', line 203

def all_fail(*cmds)
  cmds.map { |cmd| fails(cmd) }
end

#all_succeed(*cmds) ⇒ Array<Array<[Integer, String]>>

Execute all commands and check that they all succeed

Parameters:

  • cmds (String)

Returns:

  • (Array<Array<[Integer, String]>>) 


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# File 'lib/osvm/shell.rb', line 196

def all_succeed(*cmds)
  cmds.map { |cmd| succeeds(cmd) }
end

#chardev_id ⇒ Object 



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# File 'lib/osvm/shell.rb', line 53

def chardev_id
  index == 0 ? 'shell' : "shell#{index}"
end

#cleanup ⇒ Object 



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# File 'lib/osvm/shell.rb', line 81

def cleanup
  File.unlink(socket_path)
rescue Errno::ENOENT
  # ignore
end

#close ⇒ Object 



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# File 'lib/osvm/shell.rb', line 61

def close
  begin
    server&.close
  rescue IOError
    # ignore
  ensure
    @server = nil
  end

  begin
    io&.close
  rescue IOError
    # ignore
  ensure
    @io = nil
  end

  @up = false
end

#execute(cmd, timeout: @default_timeout) ⇒ Array<Integer, String>

Returns exit status and output.

Parameters:

  • cmd (String)
  • timeout (Integer) (defaults to: @default_timeout)

Returns:

  • (Array<Integer, String>) —

    exit status and output



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# File 'lib/osvm/shell.rb', line 133

def execute(cmd, timeout: @default_timeout)
  machine.raise_if_kernel_failed!
  machine.start unless machine.running?
  machine.raise_if_kernel_failed!
  wait

  mutex.synchronize do
    wait
    execute_command(cmd, timeout:)
  end
end

#execute_command(cmd, timeout:) ⇒ Object (protected) 



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# File 'lib/osvm/shell.rb', line 294

def execute_command(cmd, timeout:)
  real_timeout = [timeout, 5].max
  vm_command = "set -euo pipefail; #{cmd}"
  timeout_command = "timeout #{real_timeout}"

  # For unknown reason, the first character written to the shell is cut. Sometimes
  # more characters are lost. We therefore prefix the executed command with whitespace
  # which can be lost.
  workaround = ' ' * 10

  io.write("#{workaround}#{timeout_command} bash -c #{Shellwords.escape(vm_command)} 2>&1 | (base64 -w 0; echo)\n")
  log_started_at = log.execute_begin(cmd)

  begin
    raw_output = read_output(timeout: real_timeout + 5, command: vm_command)
  rescue MachineShellClosed
    log.execute_end(-1, '[machine shell closed]', log_started_at)
    raise
  end

  output = Base64.decode64(raw_output)

  io.write("#{workaround}echo ${PIPESTATUS[0]}\n")

  begin
    status = read_output(timeout: 60, command: 'echo ${PIPESTATUS[0]}').strip.to_i
  rescue MachineShellClosed
    log.execute_end(-1, output, log_started_at)
    raise
  end

  if timeout && status == 124
    log.execute_end(-1, output, log_started_at)
    raise TimeoutError, "Timeout occurred while running command '#{cmd}', " \
                        "output: #{output.inspect}"
  end

  log.execute_end(status, output, log_started_at)
  [status, output]
end

#expect_with_retries(cmd, attempts:, retry_delay:, timeout:, success:) ⇒ Object (protected)

Raises:



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# File 'lib/osvm/shell.rb', line 245

def expect_with_retries(cmd, attempts:, retry_delay:, timeout:, success:)
  unless attempts.is_a?(Integer) && attempts > 0
    raise ArgumentError, 'attempts must be a positive integer'
  end

  status = output = nil

  attempts.times do |attempt|
    status, output = execute(cmd, timeout:)
    matches = success ? (status == 0) : (status != 0)
    return [status, output] if matches

    sleep(retry_delay) unless attempt + 1 == attempts
  end

  if success
    raise CommandFailed, "Command '#{cmd}' failed with status #{status}. Output:\n #{output}"
  end

  raise CommandSucceeded, "Command '#{cmd}' succeeds with status #{status}. Output:\n #{output}"
end

#fails(cmd, timeout: @default_timeout) ⇒ Array<Integer, String>

Execute command and check that it fails

Parameters:

  • cmd (String)
  • timeout (Integer) (defaults to: @default_timeout)

Returns:

  • (Array<Integer, String>) 


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# File 'lib/osvm/shell.rb', line 173

def fails(cmd, timeout: @default_timeout)
  status, output = execute(cmd, timeout:)

  if status == 0
    raise CommandSucceeded, "Command '#{cmd}' succeeds with status #{status}. Output:\n #{output}"
  end

  [status, output]
end

#fails_with_retries(cmd, attempts:, retry_delay: 1, timeout: @default_timeout) ⇒ Array<Integer, String>

Execute a command repeatedly until it fails or all attempts are used

Parameters:

  • cmd (String)
  • attempts (Integer)
  • retry_delay (Numeric) (defaults to: 1)
  • timeout (Integer) (defaults to: @default_timeout) —

    timeout for each attempt

Returns:

  • (Array<Integer, String>) 


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# File 'lib/osvm/shell.rb', line 189

def fails_with_retries(cmd, attempts:, retry_delay: 1, timeout: @default_timeout)
  expect_with_retries(cmd, attempts:, retry_delay:, timeout:, success: false)
end

#finalize ⇒ Object 



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# File 'lib/osvm/shell.rb', line 87

def finalize
  log.close
end

#prepare ⇒ Object 



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# File 'lib/osvm/shell.rb', line 38

def prepare
  File.unlink(socket_path)
rescue Errno::ENOENT
  # ignore
ensure
  @server = UNIXServer.new(socket_path)
end

#qemu_options ⇒ Object 



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# File 'lib/osvm/shell.rb', line 46

def qemu_options
  [
    '-chardev', "socket,id=#{chardev_id},path=#{socket_path}",
    '-device', "virtconsole,chardev=#{chardev_id}"
  ]
end

#read_nonblock(io) ⇒ Object (protected) 



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# File 'lib/osvm/shell.rb', line 376

def read_nonblock(io)
  io.read_nonblock(4096)
rescue IO::WaitReadable
  ''
end

#read_output(timeout:, command:) ⇒ Object (protected) 



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# File 'lib/osvm/shell.rb', line 335

def read_output(timeout:, command:)
  t1 = Time.now
  buffer = ''

  loop do
    machine.raise_if_kernel_failed!

    if t1 + timeout < Time.now
      raise UnrecoverableTimeoutError, "Timeout occurred while running command '#{command}', " \
                                       "buffer contents: #{buffer.inspect}"
    end

    rs = io.wait_readable(1)
    next unless rs

    begin
      buffer << read_nonblock(io)
    rescue EOFError
      reset
      machine.raise_if_kernel_failed!
      raise MachineShellClosed
    end

    break if buffer.end_with?("\n")
  end

  buffer
end

#reset ⇒ Object (protected) 



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# File 'lib/osvm/shell.rb', line 364

def reset
  @up = false

  return if io.nil?

  io.close unless io.closed?
rescue IOError
  # ignore
ensure
  @io = nil
end

#succeeds(cmd, timeout: @default_timeout) ⇒ Array<Integer, String>

Execute command and check that it succeeds

Parameters:

  • cmd (String)
  • timeout (Integer) (defaults to: @default_timeout)

Returns:

  • (Array<Integer, String>) 


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# File 'lib/osvm/shell.rb', line 149

def succeeds(cmd, timeout: @default_timeout)
  status, output = execute(cmd, timeout:)

  if status != 0
    raise CommandFailed, "Command '#{cmd}' failed with status #{status}. Output:\n #{output}"
  end

  [status, output]
end

#succeeds_with_retries(cmd, attempts:, retry_delay: 1, timeout: @default_timeout) ⇒ Array<Integer, String>

Execute a command repeatedly until it succeeds or all attempts are used

Parameters:

  • cmd (String)
  • attempts (Integer)
  • retry_delay (Numeric) (defaults to: 1)
  • timeout (Integer) (defaults to: @default_timeout) —

    timeout for each attempt

Returns:

  • (Array<Integer, String>) 


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# File 'lib/osvm/shell.rb', line 165

def succeeds_with_retries(cmd, attempts:, retry_delay: 1, timeout: @default_timeout)
  expect_with_retries(cmd, attempts:, retry_delay:, timeout:, success: true)
end

#up? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/osvm/shell.rb', line 57

def up?
  @up
end

#wait(timeout: @default_timeout) ⇒ void

This method returns an undefined value.

Parameters:

  • timeout (Integer) (defaults to: @default_timeout) 


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# File 'lib/osvm/shell.rb', line 93

def wait(timeout: @default_timeout)
  machine.raise_if_kernel_failed!
  raise "machine #{machine.name} is not running" unless machine.running?
  return if up?

  t1 = Time.now
  buffer = ''

  loop do
    machine.raise_if_kernel_failed!

    if t1 + timeout < Time.now
      raise TimeoutError, 'Timeout occurred while waiting for shell'
    end

    reset if io&.closed?
    accept(timeout: t1 + timeout - Time.now) if io.nil?

    rs = io.wait_readable(1)
    next unless rs

    begin
      buffer << read_nonblock(io)
    rescue EOFError
      reset
      buffer = ''
      next
    end

    next unless buffer.include?("test-shell-ready\n")

    @up = true
    machine.__send__(:mount_shared_dir_once)
    return
  end
end

#wait_until_fails(cmd, timeout: @default_timeout) ⇒ Array<Integer, String>

Wait until command fails

Returns:

  • (Array<Integer, String>) 


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# File 'lib/osvm/shell.rb', line 226

def wait_until_fails(cmd, timeout: @default_timeout)
  t1 = Time.now
  cur_timeout = timeout

  loop do
    status, output = execute(cmd, timeout: cur_timeout)
    return [status, output] if status != 0

    cur_timeout = timeout - (Time.now - t1)
    raise TimeoutError, "Timeout occurred while running command '#{cmd}'" if cur_timeout <= 0

    sleep(1)
  end
end

#wait_until_succeeds(cmd, timeout: @default_timeout) ⇒ Array<Integer, String>

Wait until command succeeds

Returns:

  • (Array<Integer, String>) 


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# File 'lib/osvm/shell.rb', line 209

def wait_until_succeeds(cmd, timeout: @default_timeout)
  t1 = Time.now
  cur_timeout = timeout

  loop do
    status, output = execute(cmd, timeout: cur_timeout)
    return [status, output] if status == 0

    cur_timeout = timeout - (Time.now - t1)
    raise TimeoutError, "Timeout occurred while running command '#{cmd}'" if cur_timeout <= 0

    sleep(1)
  end
end