Net::Hadoop::WebHDFS - Client library for Hadoop WebHDFS and HttpFs
use Net::Hadoop::WebHDFS; my $client = Net::Hadoop::WebHDFS->new( host => 'hostname.local', port => 50070 ); my $statusArrayRef = $client->list('/'); my $contentData = $client->read('/data.txt'); $client->create('/foo/bar/data.bin', $bindata);
This module supports WebHDFS v1 on Hadoop 1.x (and CDH4.0.0 or later), and HttpFs on Hadoop 2.x (and CDH4 or later). WebHDFS/HttpFs has two authentication methods: pseudo authentication and Kerberos, but this module supports pseudo authentication only.
Net::Hadoop::WebHDFS class method and instance methods.
Net::Hadoop::WebHDFS->new( %args ) :Net::Hadoop::WebHDFS
Creates and returns a new client instance with %args. If you are using HttpFs, set httpfs_mode => 1 and port => 14000.
%args might be:
$client->create($path, $body, %options) :Bool
Creates file on HDFS with $body data. If you want to create blank file, pass blank string.
%options might be:
$client->append($path, $body, %options) :Bool
Append $body data to $path file.
$client->read($path, %options) :Str
Open file of $path and returns its content. Alias: open.
$client->mkdir($path, [permission => '0644']) :Bool
Make directory $path on HDFS. Alias: mkdirs.
$client->rename($path, $dest) :Bool
Rename file or directory as $dest.
$client->delete($path, [recursive => 0/1]) :Bool
Delete file $path from HDFS. With optional recursive => 1, files and directories are removed recursively (default false).
$client->stat($path) :HashRef
Get and returns file status object for $path. Alias: getfilestatus.
$client->list($path) :ArrayRef
Get list of files in directory $path, and returns these status objects arrayref. Alias: liststatus.
$client->content_summary($path) :HashRef
Get 'content summary' object and returns it. Alias: getcontentsummary.
$client->checksum($path) :HashRef
Get checksum information object for $path. Alias: getfilechecksum.
$client->homedir() :Str
Get accessing user's home directory path. Alias: gethomedirectory.
$client->chmod($path, $mode) :Bool
Set permission of $path as octal $mode. Alias: setpermission.
$client->chown($path, [owner => 'username', group => 'groupname']) :Bool
Set owner or group of $path. One of owner/group must be specified. Alias: setowner.
$client->replication($path, $replnum) :Bool
Set replica number for $path. Alias: setreplication.
$client->touch($path, [modificationtime => $mtime, accesstime => $atime]) :Bool
Set mtime/atime of $path. Alias: settimes.
$client->touchz($path) :Bool
Create a zero length file.
$client->checkaccess( $path, $fsaction ) :Bool
Test if the user has the rights to do a file system action.
$client->concat( $path, @source_paths ) :Bool
Concatenate paths.
$client->truncate( $path, $newlength ) :Bool
Truncate a path contents.
$client->delegation_token( $action, $path, @args )
This is a method wrapping the multiple methods for delegation token handling.
my $token = $client->delegation_token( get => $path ); print "Token: $token\n"; my $milisec = $client->delegation_token( renew => $token ); printf "Token expiration renewed until %s\n", scalar localtime $milisec / 1000; if ( $client->delegation_token( cancel => $token ) ) { print "Token cancelled. There will be a new one created.\n"; my $token_new = $client->delegation_token( get => $path ); print "New token: $token_new\n"; printf "New token is %s\n", $token_new eq $token ? 'the same' : 'different'; } else { warn "Failed to cancel token $token!"; }
$client->delegation_token( get => $path, [renewer => $username, service => $service, kind => $kind ] ) :Str )
Returns the delegation token id for the specified path.
$client->delegation_token( renew => $token ) :Int
Returns the new expiration time for the specified delegation token in miliseconds.
$client->delegation_token( cancel => $token ) :Bool
Cancels the specified delegation token (which will force a new one to be created.
$client->snapshot( $path, $action => @args )
This is a method wrapping the multiple methods for snapshot handling.
$client->snapshot( $path, create => [, $snapshotname ] ) :Str
Creates a new snaphot on the specified path and returns the name of the snapshot.
$client->snapshot( $path, rename => $oldsnapshotname, $snapshotname ) :Bool
Renames the snaphot.
$client->snapshot( $path, delete => $snapshotname ) :Bool
Deletes the specified snapshot.
$client->xattr( $path, $action, @args )
This is a method wrapping the multiple methods for extended attributes handling.
my @attr_names = $client->xattr( $path, 'list' ); my %attr = $client->xattr( $path, get => flatten => 1 ); if ( ! exists $attr{'user.bar'} ) { warn "set user.bar = 42\n"; $client->xattr( $path, create => 'user.bar' => 42 ) || warn "Failed to create user.bar"; } else { warn "alter user.bar = 24\n"; $client->xattr( $path, replace => 'user.bar' => 24 ) || warn "Failed to replace user.bar"; ; } if ( exists $attr{'user.foo'} ) { warn "No more foo\n"; $client->xattr( $path, remove => 'user.foo') || warn "Failed to remove user.foo"; ; }
$client->xattr( $path, get => [, names => \@attr_names] [, flatten => 1 ] [, encoding => $enc ] ) :Struct
Returns the extended attribute key/value pairs on a path. The default data set is an array of hashrefs with the pairs, however if you set <flatten> to a true value then a simple hash will be returned.
<flatten
It is also possible to fetch a subset of the attributes if you specify the names of them with the <names> option.
<names
$client->xattr( $path, 'list' ) :List
This method will return the names of all the attributes set on <$path>.
<$path
$client->xattr( $path, create => $attr_name => $value ) :Bool
It is possible to create a new extended attribute on a path with this method.
$client->xattr( $path, replace => $attr_name => $value ) :Bool
It is possible to replace the value of an existing extended attribute on a path with this method.
$client->xattr( $path, remove => $attr_name ) :Bool
Deletes the speficied attribute on <$path>.
$client->exists($path) :Bool
Returns the stat() hash if successful, and false otherwise. Dies on interface errors.
stat()
$client->find($path, $callback, $options_hash)
Loops recursively over the specified path:
$client->find( '/user', sub { my($cwd, $path) = @_; my $date = localtime $path->{modificationTime}; my $type = $path->{type} eq q{DIRECTORY} ? "[dir ]" : "[file]"; my $size = sprintf "% 10s", $path->{blockSize} ? sprintf "%.2f MB", $path->{blockSize} / 1024**2 : 0; print "$type $size $path->{permission} $path->{owner}:$path->{group} $cwd/$path->{pathSuffix}\n"; }, { # optional re_ignore => qr{ \A # Filter some filenames out even before reaching the callback [_] # logs and meta data, java junk, _SUCCESS files, etc. }xms, } );
TAGOMORI Satoshi <tagomoris {at} gmail.com>
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
To install Net::Hadoop::WebHDFS, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Net::Hadoop::WebHDFS
CPAN shell
perl -MCPAN -e shell install Net::Hadoop::WebHDFS
For more information on module installation, please visit the detailed CPAN module installation guide.