Class: OsCtl::Lib::Zfs::Stream

Inherits:
Object
  • Object
show all
Includes:
Utils::Log, Utils::System
Defined in:
lib/libosctl/zfs/stream.rb

Overview

Control class for ZFS send invocation.

Stream uses the ‘-v` flag of zfs send to monitor how the transfer progresses. The following output from zfs send is parsed:

send from <snap1> to <snap2> estimated size is <n><unit>
send from <snap2> to <snap3> estimated size is <n><unit>
send from <snap3> to <snap4> estimated size is <n><unit>
...
total estimated size is <n><unit>  # this is the size that is read
TIME        SENT         SNAPSHOT
HH:MM:SS    <n1><unit>   <snap>
HH:MM:SS    <n2><unit>   <snap>
HH:MM:SS    <n3><unit>   <snap>
TIME        SENT         SNAPSHOT
HH:MM:SS    <m1><unit>   <snap>
HH:MM:SS    <m2><unit>   <snap>
HH:MM:SS    <m3><unit>   <snap>
...

A line with column headers separates transfers of snapshots listed at the top. There might not be any transfered data between column headers if the snapshot has zero (or possibly very little) size. Time and snapshot columns are ignored, sent data are expected to increment and reset when the next snapshot is being transfered.

Instance Method Summary collapse

Methods included from Utils::System

#find_executable!, #read_process_output, #repeat_on_failure, #syscmd, #syscmd_argv, #write_stdin, #zfs

Methods included from Utils::Log

included

Constructor Details

#initialize(fs, snapshot, from_snapshot = nil, opts = {}) ⇒ Stream

Returns a new instance of Stream.

Parameters:

  • fs (String) —

    filesystem

  • snapshot (String)
  • from_snapshot (String) (defaults to: nil)
  • opts (Hash) (defaults to: {})

Options Hash (opts):

  • :intermediary (Boolean) —

    defaults to ‘true`

  • :compressed (Boolean) —

    defaults to ‘true`

  • :properties (Boolean) —

    defaults to ‘true`

  • :large_block (Boolean) —

    defaults to ‘true`



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# File 'lib/libosctl/zfs/stream.rb', line 41

def initialize(fs, snapshot, from_snapshot = nil, opts = {})
  @fs = fs
  @snapshot = snapshot
  @from_snapshot = from_snapshot
  @opts = opts
  @progress = []

  @opts[:intermediary] = true unless @opts.has_key?(:intermediary)
  @opts[:compressed] = false unless @opts.has_key?(:compressed)
  @opts[:properties] = true unless @opts.has_key?(:properties)
  @opts[:large_block] = true unless @opts.has_key?(:large_block)
end

Instance Method Details

#approximate_size ⇒ Object (protected)

Raises:

  • (ArgumentError) 


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# File 'lib/libosctl/zfs/stream.rb', line 255

def approximate_size
  opts = %w[n v]
  opts << 'c' if @opts[:compressed]

  cmd = if @from_snapshot
          zfs(:send, "-#{opts.join} -I @#{@from_snapshot}", "#{path}@#{@snapshot}")

        else
          zfs(:send, "-#{opts.join}", "#{path}@#{@snapshot}")
        end

  rx = /^total estimated size is ([^$]+)$/
  m = rx.match(cmd.output)

  raise ArgumentError, 'unable to estimate size' if m.nil?

  parse_size(m[1])
end

#full_zfs_send_cmd ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 314

def full_zfs_send_cmd
  if @from_snapshot
    i = @opts[:intermediary] ? 'I' : 'i'
    "#{zfs_send_cmd} -v -#{i} @#{@from_snapshot} #{path}@#{@snapshot}"
  else
    "#{zfs_send_cmd} -v #{path}@#{@snapshot}"
  end
end

#monitor(send) ⇒ Object

Monitor progress of spawned zfs send, needed only when using #spawn.

Parameters:

  • send (Array) —

    the second return value from #spawn



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# File 'lib/libosctl/zfs/stream.rb', line 88

def monitor(send)
  pids, err = send

  monitor_progress(err)
  err.close

  pids.each { |pid| Process.wait(pid) }
  $?
end

#monitor_progress(io) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 228

def monitor_progress(io)
  total = 0
  transfered = 0

  io.each_line do |line|
    n = parse_transfered(line)

    if n
      change = transfered == 0 ? n : n - transfered
      transfered = n
      total += change

    else # Transfer of another snapshot has begun, zfs send is counting from 0
      transfered = 0
      next
    end

    @progress.each do |block|
      block.call(total, transfered, change)
    end
  end
end

#notify_exec(pipeline) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 331

def notify_exec(pipeline); end

#parse_size(str) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 298

def parse_size(str)
  size = str.to_f
  suffix = str.strip[-1]

  if suffix !~ /^\d+$/
    units = %w[B K M G T]

    raise "unsupported suffix '#{suffix}'" unless (i = units.index(suffix))

    i.times { size *= 1024 }

  end

  (size / 1024 / 1024).round
end

#parse_total_size(fd) ⇒ Object (protected)

Reads from fd until total transfer size can be estimated.

Parameters:

  • fd (IO) —

    IO object to read



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# File 'lib/libosctl/zfs/stream.rb', line 276

def parse_total_size(fd)
  rx = /total estimated size is ([^$]+)$/

  until fd.eof?
    line = fd.readline

    m = rx.match(line)
    next if m.nil?

    return parse_size(m[1])
  end

  raise 'unable to estimate total transfer size'
end

#parse_transfered(str) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 291

def parse_transfered(str)
  cols = str.split
  return if /^\d{2}:\d{2}:\d{2}$/ !~ cols[0].strip

  parse_size(cols[1])
end

#path ⇒ String

Returns path.

Returns:

  • (String) —

    path



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# File 'lib/libosctl/zfs/stream.rb', line 147

def path
  @fs
end

#pipe_cmd(cmd) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 153

def pipe_cmd(cmd)
  @pipeline = []
  r, w = IO.pipe

  cmd_pid = Process.fork do
    $stdin.reopen(r)
    w.close
    Process.exec(*cmd)
  end

  r.close

  zfs_pid, err = zfs_send(w)
  @pipeline << Shellwords.join(cmd)

  w.close

  log(:info, :zfs, @pipeline.join(' | '))
  notify_exec(@pipeline)
  monitor_progress(err)
  err.close

  zfs_status = wait_for_pipeline_process(zfs_pid)
  cmd_status = wait_for_pipeline_process(cmd_pid)

  raise_pipeline_failure(cmd_status) unless cmd_status.success?
  raise_pipeline_failure(zfs_status) unless zfs_status.success?
end

#pipe_io(io) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 182

def pipe_io(io)
  @pipeline = []
  zfs_pid, err = zfs_send(io)

  log(:info, :zfs, @pipeline.join(' | '))
  notify_exec(@pipeline)
  monitor_progress(err)
  err.close

  Process.wait(zfs_pid)
end

#progress {|total, transfered, sent| ... } ⇒ Object

Yield Parameters:

  • total (Integer) —

    total number of transfered data

  • transfered (Integer) —

    number transfered data of the current snapshot

  • sent (Integer) —

    transfered data since the last call



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# File 'lib/libosctl/zfs/stream.rb', line 142

def progress(&block)
  @progress << block
end

#raise_pipeline_failure(status) ⇒ Object (protected)

Raises:



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# File 'lib/libosctl/zfs/stream.rb', line 199

def raise_pipeline_failure(status)
  raise Exceptions::SystemCommandFailed.new(
    @pipeline.join(' | '),
    status.exitstatus || (128 + status.termsig),
    ''
  )
end

#send_recv(fs) ⇒ Object

Send stream to a local filesystem.



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# File 'lib/libosctl/zfs/stream.rb', line 129

def send_recv(fs)
  pipe_cmd(['zfs', 'recv', '-F', fs])
end

#send_to(addr, port, opts = {}) ⇒ Object

Send stream over a socket.

Parameters:

  • addr (String)
  • port (Integer)
  • opts (Hash) (defaults to: {})

Options Hash (opts):

  • :block_size (String)
  • :buffer_size (String)
  • :log_file (String)
  • :timeout (Integer) 


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# File 'lib/libosctl/zfs/stream.rb', line 113

def send_to(addr, port, opts = {})
  cmd = [
    opts.fetch(:command, 'mbuffer'),
    '-q',
    '-O', "#{addr}:#{port}",
    '-s', opts.fetch(:block_size, '128k').to_s,
    '-m', opts.fetch(:buffer_size, '64M').to_s,
    ('-l' if opts[:log_file]),
    opts[:log_file],
    '-W', opts.fetch(:timeout, 900).to_s
  ].compact

  pipe_cmd(cmd)
end

#size ⇒ Integer

Get approximate stream size.

Returns:

  • (Integer) —

    size in MiB



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# File 'lib/libosctl/zfs/stream.rb', line 135

def size
  @size ||= approximate_size
end

#spawn ⇒ Array<IO, Array>

Spawn zfs send and return IO with its standard output

Returns:

  • (Array<IO, Array>) 


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# File 'lib/libosctl/zfs/stream.rb', line 56

def spawn
  r, w = IO.pipe
  pid, err = zfs_send(w)
  w.close
  [r, [[pid], err]]
end

#spawn_with_mbuffer(command: 'mbuffer', block_size: '128k', buffer_size: '256M', start_writing_at: 60) ⇒ Array<IO, Array>

Spawn zfs send with mbuffer and return IO with its standard output

Returns:

  • (Array<IO, Array>) 


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# File 'lib/libosctl/zfs/stream.rb', line 65

def spawn_with_mbuffer(command: 'mbuffer', block_size: '128k', buffer_size: '256M', start_writing_at: 60)
  send_r, send_w = IO.pipe
  send_pid, send_err = zfs_send(send_w)
  send_w.close

  mbuf_r, mbuf_w = IO.pipe
  mbuf_pid = Process.spawn(
    command,
    '-q',
    '-s', block_size.to_s,
    '-m', buffer_size.to_s,
    '-P', start_writing_at.to_s,
    in: send_r,
    out: mbuf_w
  )
  send_r.close
  mbuf_w.close

  [mbuf_r, [[send_pid, mbuf_pid], send_err]]
end

#update_transfered(str) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 251

def update_transfered(str)
  size = update_transfered(str)
end

#wait_for_pipeline_process(pid) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 194

def wait_for_pipeline_process(pid)
  _, status = Process.wait2(pid)
  status
end

#write_to(io) ⇒ Object

Write stream to ‘io`

Parameters:

  • io (IO) —

    writable stream



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# File 'lib/libosctl/zfs/stream.rb', line 100

def write_to(io)
  zfs_send(io)
end

#zfs_send(stdout) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 207

def zfs_send(stdout)
  r_err, w_err = IO.pipe
  cmd = full_zfs_send_cmd

  @pipeline << cmd if @pipeline

  pid = Process.fork do
    r_err.close
    $stdout.reopen(stdout)
    $stderr.reopen(w_err)

    Process.exec(cmd)
  end

  w_err.close

  @size = parse_total_size(r_err)

  [pid, r_err]
end

#zfs_send_cmd ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 323

def zfs_send_cmd
  cmd = %w[zfs send]
  cmd << '-c' if @opts[:compressed]
  cmd << '-p' if @opts[:properties]
  cmd << '-L' if @opts[:large_block]
  cmd.join(' ')
end