NAME

SGI::FAM - Perl interface to SGI/Irix File Access Monitor

SYNOPSIS

  use SGI::FAM;
  my $fam=new SGI::FAM;
  $fam->monitor('/foo');
  $fam->monitor('/foo/bar.txt');
  while (1) {
    my $event=$fam->next_event; # Blocks
    print "Pathname: ", $event->filename,
      " Event: ", $event->type, "\n";
  }

Asynchronous mode:

  while ($fam->pending) {
    my $event=$fam->next_event; # Immediate
    ...
  }
  # Do something else

DESCRIPTION

Provides a somewhat higher-level and friendlier interface to the SGI/Irix File Access Monitor API. This allows one to monitor both local and remote (NFS-mounted) files and directories for common filesystem events. To do so, you must register "monitors" on specified pathnames and wait for events to arrive pertaining to them. To get a full description of the API, you should see fam(3x).

Since FAM only deals with absolute pathnames, all paths are canonicalized internally and monitors are held on canonical paths. Whenever a path is returned from this module, howvever, via which or monitored with no arguments, the originally specified path is given for convenience.

MAIN METHODS

new [ appname ]

Create a new FAM connection. An application name may be given.

pending

True if there is an event waiting. Returns immediately.

debug_level [ level ]

Set or query debug level. Values are FAM_DEBUG_OFF, FAM_DEBUG_ON, and FAM_DEBUG_VERBOSE (you should ask to import these).

next_event

Returns next event in queue, as an event object. Blocks if necessary until one is available.

monitor path [ unique [ type [ depth mask ] ] ]

Monitor the specified file or directory. Expect a slew of events immediately (exist and end_exist) which may not interest you.

unique, if specified and true, will produce a warning if the monitored path is not unique among those already being monitored. This can be helpful for debugging, but normally this is harmless.

type may be file, dir or coll; it defaults to file or dir according to an existing filesystem entry. If you specify coll (collection), pass additional depth and mask arguments, if you ever figure out what that does (SGI does not say).

cancel path

Stop monitoring this path.

monitored [ path ]

List all currently monitored paths, or check if a specific one is being monitored. Does not check if a monitor is suspended.

suspended path

True if the specified monitor is suspended.

suspend [ path ]

Suspend monitoring of a path, or all paths if unspecified.

resume [ path ]

Resume monitoring of a path, or all paths if unspecified.

which event

Gives the pathname for the monitor generating this event. Often this will be the same as $event->filename, but will differ in some cases, e.g. in create events where filename will yield the basename of the new file while the which method must be invoked to determine the directory of creation, if more than one is being monitored.

EVENT METHODS

hostname

Host of event. Does not seem to work, actually.

filename

Path of event, according to FAM.

type

Type of event; one of the following strings: change, delete, start_exec, stop_exec, create, move, ack, exist, end_exist.

BUGS

Most of these can be observed with monitor.

Hostnames

Do not seem to be supplied at all.

Timing

Is somewhat erratic. For example, creating a file that had been monitored and deleted will signal a create event on it, after about a second pause.

Execute Events

Are not sent, as far as the author can determine.

SEE ALSO

For the raw SGI interface (rather poorly documented), see fam(3x).

AUTHORS

J. Glick jglick@sig.bsh.com.

REVISION

lib/SGI/FAM.pm last modified Thu, 25 Sep 1997 22:56:42 -0400 release 1.002. Copyright (c) 1997 Strategic Interactive Group. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

cpanm SGI::FAM

perl -MCPAN -e shell
install SGI::FAM