The pantasks "server" mode allows to pantasks to run using a server/client interface. This is especially handy if you want to be able to control pantasks from multiple locations (e.g., check processing from home) or accounts (e.g., multiple people controlling or eavesdropping on the processing).

There is a small convenience issue when running pantasks in the "server" mode: some commands which you would usually run in a standalone pantasks are only available when wrapped inside a macro; see below.

Configuration

Ensure the following is in your ~/.ptolemyrc file:

PANTASKS_SERVER         XXXXX.ifa.hawaii.edu
PASSWORD                XXXXX
#PANTASKS_SERVER_STDOUT  pantasks.stdout.log
#PANTASKS_SERVER_STDERR  pantasks.stderr.log

• PANTASKS_SERVER defines the name of the server for the client to connect to. There's no real need to update this, since we'll use a script to set this on the fly, allowing multiple pantasks servers to be used simultaneously.
• PASSWORD provides minimal access control for the pantasks server. Set this to a unique word.
• PANTASKS_SERVER_STDOUT and PANTASKS_SERVER_STDERR define where the output goes that is usually displayed in the pantasks session. Since setting these also affects the standalone version of pantasks, I recommend leaving them commented out; we'll use a script to set them on the fly.

If you are using Nebulous, you will also need to set up an ipphosts.config file. This config file has METADATA cards that assign a particular host to each chip on the camera, so that nebulous can distribute every exposure consistently, without piling too many chips onto the same machine. There is also a metadata card for indicating which hosts are to be used for skycell processing. Here is an example of how this config file should look:

ipphosts MULTI

ipphosts METADATA
  camera STR skycell
  count S32  8
  sky00 STR  ipp006
  sky01 STR  ipp007
  sky02 STR  ipp008 
  sky03 STR  ipp009
  sky04 STR  ipp010
  sky05 STR  ipp011
  sky06 STR  ipp020
  sky07 STR  ipp021
END

ipphosts METADATA
  camera STR GPC1

  XY01  STR  ipp014
  XY02  STR  ipp014
  XY03  STR  ipp014
  XY04  STR  ipp014

  XY05  STR  ipp023
  XY06  STR  ipp023
  XY10  STR  ipp023
  XY11  STR  ipp023

  XY12  STR  ipp024
  XY13  STR  ipp024

  < etc. ...  >

  XY75  STR  ipp015
  XY76  STR  ipp015
END

Helpful scripts

Here are some convenient scripts for starting the pantasks server and client.

• Save the following script as start_pantasks_server in some directory on your path

  #!/bin/bash
  # Start up a pantasks server
  # Output is redirected to files
                                                                                  
  server_redirect="-D PANTASKS_SERVER_STDOUT pantasks.stdout.log -D PANTASKS_SERVER_STDERR pantasks.stderr.log"
                                                                                  
  echo pantasks_server $server_redirect
  pantasks_server $server_redirect
  

• Save this one as start_pantasks_client on your path

#!/bin/bash
# start up pantasks_client
# 1st argument is the name of the host to connect to
                                                                                
server_arg=""
server_host=$1
                                                                                
if [ $server_host ]; then
   server_arg="-D PANTASKS_SERVER $server_host"
   echo pantasks_client $server_arg
   pantasks_client $server_arg
else 
   echo "Please provide the hostname of the pantasks server."
fi

Starting pantasks

Starting the server is as easy as:

% start_pantasks_server
bound to port: 2000

You can start it in the background if you want: it's not going to print anything more to the terminal.

In a different window (or machine or user), start the client:

% start_pantasks_client mymachine

where mymachine is the name of the machine on which the server is running.

You should be presented with the usual pantasks environment. However, some things are subtly different: the environment you see before you is particular to the client, not the server, and it's the server that runs everything. This is important to keep in mind, and it means that you should bury within macros some commands that you would ordinarily just type on the pantasks command-line.

Setting up

Here are some useful definitions for controlling pantasks using the server mode:

• Save this as server.pro in your pantasks modules directory

macro setup
    $LABEL = "my_label"
    $DBNAME = "mydatabase"
    module pantasks.pro
    module.tasks
    all.off
	 # NEXT LINES ARE ONLY NEEDED IF USING NEBULOUS
    $default_host = machine1
    queueload tmp -x "cat ipphosts.config"
    ipptool2book tmp ipphosts -key camera
	 # END NEBULOUS ONLY
    add.database $DBNAME
    echo Using database $DBNAME
    echo Current active label is $LABEL
end
 
macro change_label
    $LABEL = $1
    echo Current active label is $LABEL
end
 
macro print_label
    echo Current active label is $LABEL
end

macro machines
    controller host add machine1 -threads $1
    controller host add machine2 -threads $1
    controller host add machine3 -threads $1
    controller host add machine4 -threads $1
end

• If you're not using Nebulous, you can remove the lines that are specific to Nebulous use (these send jobs to particular machines).
• Ensure the my_label is changed to the label of the data you're processing (or "NONE" including quotes if none).
• Ensure the my_database is changed to the database you're using.
• Ensure the machineN are changed according to your system.

So, now in the pantasks client, you can say:

pantasks: server input server.pro

to load the macro file. Note that the server has to do this command, hence the prefix server.

Note: I (Eric Tittley) believe the above command should be:

pantasks: server module server.pro

Bill, can you verify?

Here is how you would set up for processing, and add hosts with a maximum of 4 threads each:

pantasks: setup
pantasks: machines 4

Now you should be able to simply say:

pantasks: run

and pantasks will run as usual. The status, stop and halt commands are also available as usual (no need to prepend {{server}}} or anything like that). But if you want to change the label, then you should do:

pantasks: change_label "new_label"

whereas in the standalone pantasks, you could have done:

pantasks: $LABEL = "new_label"

Such commands now have to be buried within macros.

Shutdown

You can quit out of the client at any time by saying:

pantasks: quit

This does not stop the server from continuing to process. You can reconnect to the server as you please.

When you're all done, you can force the server to quit by issuing the following command from the client:

pantasks: shutdown now