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

#repeat_on_failure, #syscmd, #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):

  • compressed (Boolean) —

    defaults to `true`



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# File 'lib/libosctl/zfs/stream.rb', line 36

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

  @opts[:compressed] = true unless @opts.has_key?(:compressed)
end

Instance Method Details

#approximate_size ⇒ Object (protected)

Raises:

  • (ArgumentError) 


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# File 'lib/libosctl/zfs/stream.rb', line 193

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

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

  else
    cmd = 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

#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 57

def monitor(send)
  pid, err = send

  monitor_progress(err)
  err.close

  Process.wait(pid)
end

#monitor_progress(io) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 166

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 263

def notify_exec(pipeline)

end

#parse_size(str) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 236

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

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

    if i = units.index(suffix)
      i.times { size *= 1024 }

    else
      fail "unsupported suffix '#{suffix}'"
    end
  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 214

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

  until fd.eof? do
    line = fd.readline

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

    return parse_size(m[1])
  end

  fail 'unable to estimate total transfer size'
end

#parse_transfered(str) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 229

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 96

def path
  @fs
end

#pipe_cmd(cmd) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 101

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 << cmd

  w.close

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

  Process.wait(zfs_pid)
  Process.wait(cmd_pid)
end

#pipe_io(io) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 127

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 91

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

#send_recv(fs) ⇒ Object

Send stream to a local filesystem.



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# File 'lib/libosctl/zfs/stream.rb', line 78

def send_recv(fs)
  pipe_cmd("zfs recv -F #{fs}")
end

#send_to(addr, port: nil) ⇒ Object

Send stream over a socket.



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# File 'lib/libosctl/zfs/stream.rb', line 73

def send_to(addr, port: nil)
  pipe_cmd("nc -N #{addr} #{port}")
end

#size ⇒ Integer

Get approximate stream size.

Returns:

  • (Integer) —

    size in MiB



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# File 'lib/libosctl/zfs/stream.rb', line 84

def size
  @size ||= approximate_size
end

#spawn ⇒ IO

Spawn zfs send and return IO with its standard output

Returns:

  • (IO) 


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# File 'lib/libosctl/zfs/stream.rb', line 48

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

#update_transfered(str) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 189

def update_transfered(str)
  size = update_transfered(str)
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 68

def write_to(io)
  zfs_send(io)
end

#zfs_send(stdout) ⇒ Object (protected) 



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# File 'lib/libosctl/zfs/stream.rb', line 139

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

  if @from_snapshot
    cmd = "#{zfs_send_cmd} -v -I @#{@from_snapshot} #{path}@#{@snapshot}"

  else
    cmd = "#{zfs_send_cmd} -v #{path}@#{@snapshot}"
  end

  @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 254

def zfs_send_cmd
  if @opts[:compressed]
    'zfs send -c'

  else
    'zfs send'
  end
end