Module: Snapsync::Btrfs

Defined in:
lib/snapsync/btrfs.rb

Defined Under Namespace

Classes: Error, UnexpectedBtrfsOutput

Class Method Summary collapse

Class Method Details

.btrfs_prog ⇒ Object 



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# File 'lib/snapsync/btrfs.rb', line 23

def self.btrfs_prog
    ENV['BTRFS_PROG'] || 'btrfs'
end

.find_new(subvolume_dir, last_gen) {|a| ... } ⇒ Object .find_new(subvolume_dir, last_gen) ⇒ #each

Facade for ‘btrfs subvolume find-new’

It computes what changed between a reference generation of a subvolume, and that subvolume’s current state

Overloads:

  • .find_new(subvolume_dir, last_gen) {|a| ... } ⇒ Object

    Yield Parameters:

    • a (String) —

      line of the find-new output

  • .find_new(subvolume_dir, last_gen) ⇒ #each

    Returns an enumeration of the lines of the find-new output.

    Returns:

    • (#each) —

      an enumeration of the lines of the find-new output

Parameters:

  • subvolume_dir (String) —

    the subvolume target of find-new

  • last_gen (Integer) —

    the reference generation



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# File 'lib/snapsync/btrfs.rb', line 97

def self.find_new(subvolume_dir, last_gen, &block)
    run('subvolume', 'find-new', subvolume_dir.to_s, last_gen.to_s).
        each_line(&block)
end

.generation_of(path) ⇒ Integer

Facade for finding the generation of a subvolume using ‘btrfs show’

Parameters:

  • path (Pathname) —

    the subvolume path

Returns:

  • (Integer) —

    the subvolume’s generation



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# File 'lib/snapsync/btrfs.rb', line 75

def self.generation_of(path)
    info = Btrfs.run('subvolume', 'show', path.to_s)
    if info =~ /Generation[^:]*:\s+(\d+)/
        Integer($1)
    else
        raise UnexpectedBtrfsOutput, "unexpected output for 'btrfs subvolume show', expected #{info} to contain a Generation: line"
    end
end

.popen(*args, mode: 'r', raise_on_error: true, **options) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

A IO.popen-like API to btrfs subcommands



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# File 'lib/snapsync/btrfs.rb', line 30

def self.popen(*args, mode: 'r', raise_on_error: true, **options)
    err_r, err_w = IO.pipe

    block_error, block_result = nil
    IO.popen([btrfs_prog, *args, err: err_w, **options], mode) do |io|
        err_w.close

        begin
            block_result = yield(io)
        rescue Error
            raise
        rescue Exception => block_error
        end
    end

    if $?.success? && !block_error
        block_result
    elsif raise_on_error
        if block_error
            raise Error.new, block_error.message
        else
            raise Error.new, "btrfs failed"
        end
    end

rescue Error => e
    prefix = args.join(" ")
    lines = err_r.readlines.map do |line|
        "#{prefix}: #{line.chomp}"
    end
    raise Error.new(e.error_lines + lines), e.message, e.backtrace

ensure err_r.close
end

.run(*args, **options) ⇒ Object 



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# File 'lib/snapsync/btrfs.rb', line 65

def self.run(*args, **options)
    popen(*args, **options) do |io|
        io.read.encode('utf-8', undef: :replace, invalid: :replace)
    end
end