Class: Distem::Lib::FileManager

Inherits:
Object
  • Object
show all
Defined in:
lib/distem/distemlib/filemanager.rb

Overview

Class that allow to manage files and archives (extracting, downloading, …)

Constant Summary

PATH_DEFAULT_DOWNLOAD =

The directory used to store downloaded files

'/tmp/distem/downloads/'
PATH_DEFAULT_CACHE =

The directory used to store archive extraction cache

'/tmp/distem/extractcache/'
PATH_DEFAULT_COMPRESS =

The directory used to store compressed files

'/tmp/distem/files/'
BIN_TAR =

:nodoc:

'tar'
@@lock =

:nodoc:

Mutex.new
@@hashcache = 
{}
@@archivecache =

:nodoc:

[]
@@cowcache =

:nodoc:

[]

Class Method Summary (collapse)

Class Method Details

+ (Object) cache_archive(archivefile, filehash, cow)

Cache an archive fine in the cache. Only one file can be cached at the same time (mutex).

Attributes

  • archivefile The path to the archive file (String)

  • filehash The hash of the archive file (String)

Returns

String value describing the path to the directory (on the local machine) the file was cached to



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# File 'lib/distem/distemlib/filemanager.rb', line 124

def self.cache_archive(archivefile,filehash,cow)
  Lib::Shell.run("mkdir -p #{PATH_DEFAULT_CACHE}") if !File.exist?(PATH_DEFAULT_CACHE)
  cachedir = File.join(PATH_DEFAULT_CACHE,filehash)
  newcache = false

  unless @@archivecache.include?(filehash)
    @@archivecache << filehash
    if File.exist?(cachedir)
      Lib::Shell.run("rm -R #{cachedir}")
    end
    if cow
      Lib::Shell.run("btrfs subvolume create #{cachedir}")
      @@cowcache << cachedir
    end
    extract!(archivefile,cachedir)
    newcache = true
  end
  return cachedir,newcache
end

+ (Object) clean_cache 



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# File 'lib/distem/distemlib/filemanager.rb', line 145

def self.clean_cache
  @@lock.synchronize {
    @@cowcache.each { |path|
      Lib::Shell.run("btrfs subvolume delete #{path}")
    }
  }
end

+ (Object) compress(filepath)

Compress a file using TGZ archive format.

Attributes

  • filepath The path to the file (String)

Returns

String value describing the path to the directory (on the local machine) the generated archive file is store to

Raises:



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# File 'lib/distem/distemlib/filemanager.rb', line 159

def self.compress(filepath)
  raise Lib::ResourceNotFoundError, filepath \
    unless File.exist?(filepath)
  unless File.exist?(PATH_DEFAULT_COMPRESS)
    Lib::Shell.run("mkdir -p #{PATH_DEFAULT_COMPRESS}")
  end

  basename = File.basename(filepath)
  respath = "#{File.join(PATH_DEFAULT_COMPRESS,basename)}.tar.gz"
  Lib::Shell.run("#{BIN_TAR} czf #{respath} -C #{filepath} .")

  return respath
end

+ (Object) download(uri_str, dir = PATH_DEFAULT_DOWNLOAD)

Download a file using a specific protocol and store it on the local machine

Attributes

  • uri_str The URI of the file to download

  • dir The directory to save the file to

Returns

String value describing the path to the downloaded file on the local machine

Exceptions

  • InvalidParameterError if the specified URI is not valid

  • ResourceNotFoundError if can't reach the specified file

  • NotImplementedError if the protocol specified in the URI is not supported (atm only file:// is supported)



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# File 'lib/distem/distemlib/filemanager.rb', line 37

def self.download(uri_str,dir=PATH_DEFAULT_DOWNLOAD)
  begin
    uri = URI.parse(CGI.unescape(uri_str))
  rescue URI::InvalidURIError
    raise Lib::InvalidParameterError, uri_str
  end

  ret = ""

  case uri.scheme
    when "file"
      ret = uri.path
      raise Lib::ResourceNotFoundError, ret unless File.exist?(ret)
    else
      raise Lib::NotImplementedError, uri.scheme
  end

  return ret
end

+ (Object) extract(archivefile, targetdir = "", override = true, cow = false)

Extract an archive file in the specified directory using a cache. The cache: if unarchiving two times the same archive, the unarchive cache is used to only have to copy files from the cache (no need to unarchive another time).

Attributes

  • archivefile The path to the archive file (String)

  • targetdir The directory to unarchive the file to

Returns

String value describing the path to the directory (on the local machine) the file was unarchived to

Exceptions

  • ResourceNotFoundError if can't reach the specified archive file

  • NotImplementedError if the archive file format is not supported (available: tar, gzip, bzip, zip, (tgz,…))

Raises:



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# File 'lib/distem/distemlib/filemanager.rb', line 67

def self.extract(archivefile,targetdir="",override=true,cow=false)
  raise Lib::ResourceNotFoundError, archivefile unless File.exist?(archivefile)

  if targetdir.empty?
    targetdir = File.dirname(archivefile)
  end

  filehash = file_hash(archivefile)

  @@lock.synchronize {
    cachedir,new = cache_archive(archivefile,filehash,cow)
    exists = File.exist?(targetdir)
    if !exists or override or new
      Lib::Shell.run("rm -Rf #{targetdir}") if exists
      if cow
        Lib::Shell.run("btrfs subvolume snapshot #{cachedir} #{targetdir}")
      else
        Lib::Shell.run("mkdir -p #{targetdir}")
        Lib::Shell.run("cp -af #{File.join(cachedir,'*')} #{targetdir}")
      end
    end
  }
  return targetdir
end

+ (Object) extract!(archivefile, target_dir)

Extract an archive file in the specified directory without using the cache and the MAX_SIMULTANEOUS_EXTRACT limitation.

Attributes

  • archivefile The path to the archive file (String)

  • targetdir The directory to unarchive the file to

Returns

String value describing the path to the directory (on the local machine) the file was unarchived to

Exceptions

  • ResourceNotFoundError if can't reach the specified archive file

  • NotImplementedError if the archive file format is not supported (available: tar, gzip, bzip, zip, (tgz,…))

Raises:



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# File 'lib/distem/distemlib/filemanager.rb', line 102

def self.extract!(archivefile,target_dir)
  raise Lib::ResourceNotFoundError, archivefile \
    unless File.exist?(archivefile)

  unless File.exist?(target_dir)
    Lib::Shell.run("mkdir -p #{target_dir}")
  end

  basename = File.basename(archivefile)
  link = File.join(target_dir, basename)
  Lib::Shell.run("ln -sf #{archivefile} #{link}")
  Lib::Shell.run("(cd #{target_dir} && #{BIN_TAR} xf #{basename})")
  Lib::Shell.run("rm #{link}")
end

+ (Object) file_hash(filename)

Get a “unique” file identifier from a specific file

Attributes

  • filename The path to the file (String)

Returns

String value describing the “unique” hash



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# File 'lib/distem/distemlib/filemanager.rb', line 179

def self.file_hash(filename)
  ret = nil
  @@lock.synchronize do
    unless @@hashcache[filename] and @@hashcache[filename][:mtime] == (mtime= File.mtime(filename))
      unless @@hashcache[filename]
        mtime = File.mtime(filename) unless mtime
        sha256 = `sha256sum #{filename}|cut -f1 -d' '`.chomp
        # if sha256sum is not functional, we use the slower Ruby version
        if (sha256 == '')
          sha256 = Digest::SHA256.file(filename).hexdigest
        end
        @@hashcache[filename] = {
          :mtime => mtime,
          :hash => "#{File.basename(filename)}-#{mtime.to_i.to_s}-#{File.stat(filename).size.to_s}-#{sha256}"
        }
      end
    end
    ret = @@hashcache[filename][:hash]
  end

  return ret
end