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README.md

Build Status

NAME

rq v3.5.0-pre1 (for Ruby 1.9.x)

IMPORTANT NOTICE

The 3.5.0 version of rq is being developed! For a solid and tested rq, you still better install version 3.4.7 for Ruby 1.8! Install this as a Ruby gem

gem install rq-ruby1.8

With rq-ruby1.8 you have to symlink against the installed rq executable.

SYNOPSIS

rq queue mode [mode_args]* [options]*

ruby queue (rq) is a zero-admin zero-configuration tool used to create instant unix clusters on a multi-core machine, and/or multiple heterogeneous nodes in a network, and even in the Cloud. rq shines in its simplicity, and requires only a centrally mounted directory (e.g. NFS or sshfs) with a simple sqlite database as a distributed priority work queue.

See also INSTALL.txt, and the QUICK START below.

DESCRIPTION

ruby queue (rq) is a zero-admin zero-configuration tool used to create instant unix clusters. the simple design allows researchers with minimal unix experience to install and configure, in only a few minutes and without root privileges, a robust unix cluster capable of distributing processes to many nodes - bringing dozens of powerful cpus to their knees with a single blow. clearly this software should be kept out of the hands of free radicals, seti enthusiasts, and one mr. j safran.

the central concept of rq is that n nodes work in isolation to pull jobs from an centrally mounted nfs priority work queue in a synchronized fashion. the nodes have absolutely no knowledge of each other and all communication is done via the queue meaning that, so long as the queue is available via nfs and a single node is running jobs from it, the system will continue to process jobs. there is no centralized process whatsoever - all nodes work to take jobs from the queue and run them as fast as possible. this creates a system which load balances automatically and is robust in face of node failures.

although the rq system is simple in it's design it features powerful functionality such as priority management, predicate and sql query, compact streaming command-line processing, programmable api, hot-backup, and input/capture of the stdin/stdout/stderr io streams of remote jobs. to date rq has had no reported runtime failures and is in operation at dozens of research centers around the world. while rq is written in the Ruby programming language, there is no Ruby programming involved in using rq.

QUICK START

It is recommended to run rq with Ruby 1.9.x using rvm

install rq using rubygems, after installing sqlite 2.x (part of the gem now)

gem install rq

now rq should work

rq --help

run the integration test

test_rq.rb

set up a directory for your queue - this can be a local, or an NFS/sshfs mounted drive:

rq dir create

on every node create a queue runner, specifying the number of cores (here 8)

rq dir feed --daemon --log=rq.log --max_feed=8

submit two jobs - shell style

rq dir submit 'sleep 10'
rq dir submit 'sleep 9'

check status

rq dir status

shows

    --- 
    jobs: 
      pending: 0
      holding: 0
      running: 2
      finished: 0
      dead: 0
      total: 2
    temporal: 
      running: 
        min: {2: 00h00m03.49s}
        max: {1: 00h00m03.60s}
    performance: 
      avg_time_per_job: 00h00m00.00s
      n_jobs_in_last_hrs: 
        1: 0
        12: 0
        24: 0
    exit_status: 
      successes: 0
      failures: 0
      ok: 0

Now, that was easy!!

INSTALL

See the notice at the top of this document. Next see the ./INSTALL file, but quickly

gem >=3.4.7:

(- install sqlite2 (Debian apt-get install libsqlite0-dev))
- gem install rq-ruby1.9

Debian flavours:

see ./INSTALL file for latest

INVOCATION

the first argument to any rq command is the always the name of the queue while the second is the mode of operation. the queue name may be omitted if, and only if, the environment variable RQ_Q has been set to contain the absolute path of target queue.

for instance, the command

~ > rq queue list 

is equivalent to

~ > export RQ_Q=queue
~ > rq list

this facility can be used to create aliases for several queues, for example, a .bashrc containing

alias MYQ="RQ_Q=/path/to/myq rq"

alias MYQ2="RQ_Q=/path/to/myq2 rq"

would allow syntax like

MYQ2 submit < joblist

MODES

rq operates in modes create, submit, resubmit, list, status, delete, update, query, execute, configure, snapshot, lock, backup, rotate, feed, recover, ioview, cron, help, and a few others. the meaning of 'mode_args' will naturally change depending on the mode of operation.

the following mode abbreviations exist, note that not all modes have abbreviations

c  => create
s  => submit
r  => resubmit
l  => list
ls => list
t  => status
d  => delete
rm => delete
u  => update
q  => query
e  => execute
C  => configure
S  => snapshot
L  => lock
b  => backup
R  => rotate 
f  => feed
io => ioview
0  => stdin
1  => stdout
2  => stderr
h  => help

create, c :

creates a queue.  the queue must be located on an nfs mounted file system
visible from all nodes intended to run jobs from it.  nfs locking must be
functional on this file system.

examples :

  0) to create a queue
      ~ > rq /path/to/nfs/mounted/q create

    or, using the abbreviation

      ~ > rq /path/to/nfs/mounted/q c

submit, s :

submit jobs to a queue to be proccesed by some feeding node.  any
'mode_args' are taken as the command to run.  note that 'mode_args' are
subject to shell expansion - if you don't understand what this means do
not use this feature and pass jobs on stdin.

when running in submit mode a file may by specified as a list of commands
to run using the '--infile, -i' option.  this file is taken to be a
newline separated list of commands to submit, blank lines and comments (#)
are allowed.  if submitting a large number of jobs the input file method
is MUCH, more efficient.  if no commands are specified on the command line
rq automatically reads them from stdin.  yaml formatted files are also
allowed as input (http://www.yaml.org/) - note that the output of nearly
all rq commands is valid yaml and may, therefore, be piped as input into
the submit command.  the leading '---' of yaml file may not be omitted.

when submitting the '--priority, -p' option can be used here to determine
the priority of jobs.  priorities may be any whole number including
negative ones - zero is the default.  note that submission of a high
priority job will NOT supplant a currently running low priority job, but
higher priority jobs WILL always migrate above lower priority jobs in the
queue in order that they be run as soon as possible.  constant submission
of high priority jobs may create a starvation situation whereby low
priority jobs are never allowed to run.  avoiding this situation is the
responsibility of the user.  the only guaruntee rq makes regarding job
execution is that jobs are executed in an 'oldest-highest-priority' order
and that running jobs are never supplanted.  jobs submitted with the
'--stage' option will not be eligible to be run by any node and will
remain in a 'holding' state until updated (see update mode) into the
'pending' mode, this option allows jobs to entered, or 'staged', in the
queue and then made candidates for running at a later date.

rq allows the stdin of commands to be provided and also captures the
stdout and stderr of any job run (of course standard shell redirects may
be used as well) and all three will be stored in a directory relative the
the queue itself.  the stdin/stdout/stderr files are stored by job id and
there location (though relative to the queue) is shown in the output of
'list' (see docs for list).


examples :

  0) submit the job ls to run on some feeding host

    ~ > rq q s ls 

  1) submit the job ls to run on some feeding host, at priority 9

    ~ > rq -p9 q s ls 

  2) submit a list of jobs from file.  note the '-' used to specify
  reading jobs from stdin

    ~ > cat joblist
    job1.sh
    job2.sh
    job2.sh

    ~ > rq q submit --infile=joblist

  3) submit a joblist on stdin

    ~ > cat joblist | rq q submit -

    or

    ~ > rq q submit - <joblist

  4) submit cat as a job, providing the stdin for cat from the file cat.in

    ~ > rq q submit cat --stdin=cat.in

  5) submit cat as a job, providing the stdin for the cat job on stdin 

    ~ > cat cat.in | rq q submit cat --stdin=-

    or

    ~ > rq q submit cat --stdin=- <cat.in

  6) submit 42 priority 9 jobs from a command file, marking them as
     'important' using the '--tag, -t' option.

    ~ > wc -l cmdfile 
    42

    ~ > rq -p9 -timportant q s < cmdfile

  6) re-submit all the 'important' jobs (see 'query' section below)

    ~ > rq q query tag=important | rq q s -

  8) re-submit all jobs which are already finished (see 'list' section
     below) 

    ~ > rq q l f | rq q s 


  9) stage the job wont_run_yet to the queue in a 'holding' state.  no
     feeder will run this job until it's state is upgraded to 'pending'

    ~ > rq q s --stage wont_run_yet

resubmit, r :

resubmit jobs back to a queue to be proccesed by a feeding node.  resubmit
is essentially equivalent to submitting a job that is already in the queue
as a new job and then deleting the original job except that using resubmit
is atomic and, therefore, safer and more efficient.  resubmission respects
any previous stdin provided for job input.  read docs for delete and
submit for more info.

examples :

  0) resubmit job 42 to the queue

    ~> rq q resubmit 42

  1) resubmit all failed jobs

    ~> rq q query exit_status!=0 | rq q resubmit -

  2) resubmit job 4242 with different stdin

    ~ rq q resubmit 4242 --stdin=new_stdin.in

list, l, ls :

list mode lists jobs of a certain state or job id.  state may be one of
pending, holding, running, finished, dead, or all.  any 'mode_args' that
are numbers are taken to be job id's to list.

states may be abbreviated to uniqueness, therefore the following shortcuts
apply :        

  p => pending
  h => holding
  r => running
  f => finished
  d => dead
  a => all

examples :

  0) show everything in q
      ~ > rq q list all

    or

      ~ > rq q l all

    or

      ~ > export RQ_Q=q 
      ~ > rq l

  1) show q's pending jobs
      ~ > rq q list pending

     note that you can achieve the same with

      ~ > rq q query state=running

  2) show q's running jobs
      ~ > rq q list running 

  3) show q's finished jobs
      ~ > rq q list finished 

  4) show job id 42 
      ~ > rq q l 42 

  5) show q's holding jobs
      ~ > rq q list holding 

status, t :

status mode shows the global state the queue and statistics on it's the
cluster's performance.  there are no 'mode_args'.  the meaning of each
state is as follows:

  pending  => no feeder has yet taken this job
  holding  => a hold has been placed on this job, thus no feeder will start
              it
  running  => a feeder has taken this job
  finished => a feeder has finished this job
  dead     => rq died while running a job, has restarted, and moved
              this job to the dead state

note that rq cannot move jobs into the dead state unless it has been
restarted.  this is because no node has any knowledge of other nodes and
cannot possibly know if a job was started on a node that subsequently
died, or that it is simply taking a very long time to complete.  only the
node that dies, upon restart, can determine that it owns jobs that 'were
started before it started running jobs', an impossibility, and move these
jobs into the dead state.  

normally only a machine crash would cause a job to be placed into the dead
state.  dead jobs are automatically restarted if, and only if, the job was
submitted with the '--restartable' flag.

status breaks down a variety of canned statistics about a nodes'
performance based solely on the jobs currently in the queue.  only one
option affects the ouput: '--exit'.  this option is used to specify
additionaly exit code mappings on which to report.  normally rq will
report any job with an exit code of 0 as being 'successes' and any job
with an exit code that is not 0, or a status of 'dead', as being
'failures'.  if the '--exit' switch is used then additional mappings can
be specified, note that the the semantics for 'successes' and 'failures'
does not change - this keyword specifies extra mappings.

examples :

  0) show q's status

    ~ > rq q t 

  2) show q's status, consider any exit code of 42 will be listed as 'ok'

    ~ > rq q t --exit ok=42

  3) show q's status, consider any exit code of 42 or 43 will be listed as
  'ok' and 127 will be listed as 'command_not_found'.  notice the quoting
  required.

    ~ > rq q t --exit 'ok=42,43 command_not_found=127'

delete, d :

delete combinations of pending, holding, finished, dead, or jobs specified
by jid.  the delete mode is capable of parsing the output of list and
query modes, making it possible to create custom filters to delete jobs
meeting very specific conditions.

'mode_args' are the same as for list.  

note that it is NOT possible to delete a running job.  rq has a
decentralized architechture which means that compute nodes are completely
independant of one another; an extension is that there is no way to
communicate the deletion of a running job from the queue the the node
actually running that job.  it is not an error to force a job to die
prematurely using a facility such as an ssh command spawned on the remote
host to kill it.  once a job has been noted to have finished, whatever the
exit status, it can be deleted from the queue.

examples :

  0) delete all pending, finished, and dead jobs from a queue

    ~ > rq q d all

  1) delete all pending jobs from a queue

    ~ > rq q d p 

  2) delete all finished jobs from a queue

    ~ > rq q d f 

  3) delete jobs via hand crafted filter program

    ~ > rq q list | yaml_filter_prog | rq q d -

    an example ruby filter program (you have to love this)

      ~ > cat yaml_filter_prog
      require 'yaml'
      joblist = YAML::load STDIN
      y joblist.select{|job| job['command'] =~ /bombing_program/}

    this program reads the list of jobs (yaml) from stdin and then dumps
    only those jobs whose command matches 'bombing_program', which is
    subsequently piped to the delete command.

update, u :

update assumes all leading arguments are jids to update with subsequent
key=value pairs.  currently only the 'command', 'priority', and 'tag'
fields of pending jobs can be generically updated and the 'state' field
may be toggled between pending and holding.

examples:

  0) update the priority of job 42 

    ~ > rq q update 42 priority=7 

  1) update the priority of all pending jobs 

    ~ > rq q update pending priority=7 

  2) query jobs with a command matching 'foobar' and update their command
  to be 'barfoo'

    ~ > rq q q "command like '%foobar%'" |\
        rq q u command=barfoo 

  3) place a hold on jid 2

    ~ > rq q u 2 state=holding

  4) place a hold on all jobs with tag=disk_filler

    ~ > rq q q tag=disk_filler | rq q u state=holding -

  5) remove the hold on jid 2

    ~ > rq q u 2 state=pending

query, q :

query exposes the database more directly the user, evaluating the where
clause specified on the command line (or read from stdin).  this feature
can be used to make a fine grained slection of jobs for reporting or as
input into the delete command.  you must have a basic understanding of SQL
syntax to use this feature, but it is fairly intuitive in this limited
capacity.

examples:

  0) show all jobs submitted within a specific 10 minute range

    ~ > a='2004-06-29 22:51:00'

    ~ > b='2004-06-29 22:51:10'

    ~ > rq q query "started >= '$a' and started < '$b'"

  1) shell quoting can be tricky here so input on stdin is also allowed to
  avoid shell expansion

    ~ > cat constraints.txt 
    started >= '2004-06-29 22:51:00' and
    started < '2004-06-29 22:51:10'

    ~ > rq q query < contraints.txt
      or (same thing)

    ~ > cat contraints.txt| rq q query -

  2) this query output might then be used to delete those jobs

    ~ > cat contraints.txt | rq q q - | rq q d -

  3) show all jobs which are either finished or dead 

    ~ > rq q q "state='finished' or state='dead'"

  4) show all jobs which have non-zero exit status

    ~ > rq q query exit_status!=0 

  5) if you plan to query groups of jobs with some common feature consider
  using the '--tag, -t' feature of the submit mode which allows a user to
  tag a job with a user defined string which can then be used to easily
  query that job group 

    ~ > rq q submit --tag=my_jobs - < joblist 

    ~ > rq q query tag=my_jobs 


  6) in general all but numbers will need to be surrounded by single
  quotes unless the query is a 'simple' one.  a simple query is a query
  with no boolean operators, not quotes, and where every part of it looks
  like

        key op value

     with ** NO SPACES ** between key, op, and value.  if, and only if,
     the query is 'simple' rq will contruct the where clause
     appropriately.  the operators accepted, and their meanings, are

       =  : equivalence : sql =
       =~ : matches     : sql like
       !~ : not matches : sql not like

     match, in the context is ** NOT ** a regular expression but a sql
     style string match.  about all you need to know about sql matches is
     that the '%' char matches anything.  multiple simple queries will be
     joined with boolean 'and'

     this sounds confusing - it isn't.  here are some examples of simple
     queries

     6.a) 
       query :
         rq q query tag=important

       where_clause :
         "( tag = 'important' )"

     6.b) 
       query :
         rq q q priority=6 restartable=true 

       where_clause :
         "( priority = 6 ) and ( restartable = 'true' )"

     6.c) 
       query :
         rq q q command=~%bombing_job% runner=~%node_1% 

       where_clause :
         "( command like '%bombing_job%') and (runner like '%node_1%')"

execute, e :

execute mode is to be used by expert users with a knowledge of sql syntax
only.  it follows the locking protocol used by rq and then allows the user
to execute arbitrary sql on the queue.  unlike query mode a write lock on
the queue is obtained allowing a user to definitively shoot themselves in
the foot.  for details on a queue's schema the file 'db.schema' in the
queue directory should be examined.

  examples :

    0) list all jobs

      ~ > rq q execute 'select * from jobs'

configure, C :

this mode is not supported yet.

snapshot, p :

snapshot provides a means of taking a snapshot of the q. use this feature
when many queries are going to be run; for example when attempting to
figure out a complex pipeline command your test queries will not compete
with the feeders for the queue's lock.  you should use this option
whenever possible to avoid lock competition.

examples:

  0) take a snapshot using default snapshot naming, which is made via the
  basename of the q plus '.snapshot'

    ~ > rq /path/to/nfs/q snapshot 

  1) use this snapshot to chceck status

    ~ > rq ./q.snapshot status 

  2) use the snapshot to see what's running on which host

    ~ > rq ./q.snapshot list running | grep `hostname` 

note that there is also a snapshot option - this option is not the same as
the snapshot command.  the option can be applied to ANY command. if in
effect then that command will be run on a snapshot of the database and the
snapshot then immediately deleted.  this is really only useful if one were
to need to run a command against a very heavily loaded queue and did not
wish to wait to obtain the lock.  eg.

  0) get the status of a heavily loaded queue

    ~ > rq q t --snapshot

  1) same as above 

    ~ > rq q t -s

** IMPORTANT **

  a really great way to hang all processing in your queue is to do this

    rq q list | less

  and then leave for the night.  you hold a read lock you won't release
  until less dies.  this is what snapshot is made for!  use it like

    rq q list -s | less

  now you've taken a snapshot of the queue to list so your locks affect no
  one.

lock, L :

lock the queue and then execute an arbitrary shell command.  lock mode
uses the queue's locking protocol to safely obtain a lock of the specified
type and execute a command on the user's behalf.  lock type must be one of

  (r)ead | (sh)ared | (w)rite | (ex)clusive

examples :

  0) get a read lock on the queue and make a backup

    ~ > rq q L read -- cp -r q q.bak

    (the '--' is needed to tell rq to stop parsing command line
     options which allows the '-r' to be passed to the 'cp' command)

** IMPORTANT **

  this is another fantastic way to freeze your queue - use with care!

backup, b :

backup mode is exactly the same as getting a read lock on the queue and
making a copy of it.  this mode is provided as a convenience.

  0) make a backup of the queue using default naming ( qname + timestamp + .bak )

    ~ > rq q b

  1) make a backup of the queue as 'q.bak' 

    ~ > rq q b q.bak

rotate, r :

rotate mode is conceptually similar to log rolling.  normally the list of
finished jobs will grow without bound in a queue unless they are manually
deleted.  rotation is a method of trimming finished jobs from a queue
without deleting them.  the method used is that the queue is copied to a
'rotation'; all jobs that are dead or finished are deleted from the
original queue and all pending and running jobs are deleted from the
rotation.  in this way the rotation becomes a record of the queue's
finished and dead jobs at the time the rotation was made.

  0) rotate a queue using default rotation name 

    ~ > rq q rotate 

  1) rotate a queue naming the rotation

    ~ > rq q rotate q.rotation

  2) a crontab entry like this could be used to rotate a queue daily 

    59 23 * * * rq q rotate `date +q.%Y%m%d`

feed, f :

take jobs from the queue and run them on behalf of the submitter as
quickly as possible.  jobs are taken from the queue in an 'oldest highest
priority' first order.  

feeders can be run from any number of nodes allowing you to harness the
CPU power of many nodes simoultaneously in order to more effectively
clobber your network, anoy your sysads, and set output raids on fire.

the most useful method of feeding from a queue is to do so in daemon mode
so that if the process loses it's controling terminal it will not exit
when you exit your terminal session.  use the '--daemon, -d' option to
accomplish this.  by default only one feeding process per host per queue
is allowed to run at any given moment.  because of this it is acceptable
to start a feeder at some regular interval from a cron entry since, if a
feeder is alreay running, the process will simply exit and otherwise a new
feeder will be started.  in this way you may keep feeder processing
running even acroess machine reboots without requiring sysad intervention
to add an entry to the machine's startup tasks.


examples :

  0) feed from a queue verbosely for debugging purposes, using a minimum
  and maximum polling time of 2 and 4 respectively.  you would NEVER
  specify polling times this brief except for debugging purposes!!!

    ~ > rq q feed -v4 --min_sleep=2 --max_sleep=4

  1) same as above, but viewing the executed sql as it is sent to the
  database

    ~ > RQ_SQL_DEBUG=1 rq q feed -v4 --min_sleep=2 --max_sleep=4

  2) feed from a queue in daemon mode - logging to /home/ahoward/rq.log

    ~ > rq q feed --daemon -l/home/$USER/rq.log

     log rolling in daemon mode is automatic so your logs should never
     need to be deleted to prevent disk overflow.

start :

the start mode is equivalent to running the feed mode except the --daemon
is implied so the process instantly goes into the background.  also, if no
log (--log) is specified in start mode a default one is used.  the default
is /home/$USER/$BASENAME_OF_Q.log

examples :

  0) start a daemon process feeding from q

    ~ > rq q start

  1) use something like this sample crontab entry to keep a feeder running
  forever - it attempts to (re)start every fifteen minutes but exits if
  another process is already feeding.  output is only created when the
  daemon is started so your mailbox will not fill up with this crontab
  entry:

    #
    # crontab.sample 
    #

    */15 * * * * /path/to/bin/rq /path/to/q start

  and entry like this on every node in your cluster is all that's needed
  to keep your cluster going - even after a reboot.

shutdown :

tell a running feeder to finish any pending jobs and then to exit.  this
is equivalent to sending signal 'SIGTERM' to the process - this is what
using 'kill pid' does by default.

examples :

  0) stop a feeding process, if any, that is feeding from q.  allow all
  jobs to be finished first.

    ~ > rq q shutdown 

** VERY IMPORTANT **

  if you are keeping your feeder alive with a crontab entry you'll need to
    comment it out before doing this or else it will simply re-start!!!

stop :

tell any running feeder to stop NOW.  this sends signal 'SIGKILL' (-9) to
the feeder process.  the same warning as for shutdown applies!!!

examples :

  0) stop a feeding process, if any, that is feeding from q.  allow NO
  jobs to be finished first - exit instantly.

    ~ > rq q stop 

cron :

when given 'start' for 'mode_args' this option automatically adds a
crontab entry to keep a feeder alive indefinitely and starts a feeder in
the background.  this is a shortcut to start a feeder and ensure it stays
running forever, even across re-boots.

'stop' as an argument applys the inverse option: any crontab entry is
removed and the daemon shutdown nicely.  a second argument of 'hard' will
do a stop instead of a shutdown.

the addition and subtraction of crontab entries is robust, however, if you
already have crontab lines maintaining your feeders with a vastly
different syntax it would be best to shut down, remove them, and then let
rq manage them.  then again, some people are quite brave...

examples :

  0) automatically add crontab entry and start daemon feeder

    ~ > rq q cron start

  1) automatically remove crontab entry and shutdown daemon feeder nicely 

    ~ > rq q cron shutdown

  2) the same, but using stop instead of shutdown

    ~ > rq q cron stop

pid :

show the pid, if any, of the feeder on this host

~ > rq q feeder
---
pid : 3176

ioview, io :

as shown in the description for submit, a job maybe be provided stdin
during job submission.  the stdout and stderr of the job are also captured
as the job is run.  all three streams are captured in files located
relative to the queue.  so, if one has submitted a job, and it's jid was
shown to be 42, by using something like

  ~ > rq /path/to/q submit myjob --stdin=myjob.in
  ---
  -
    jid : 42
    priority : 0
    ...
    stdin : stdin/42
    stdout : stdout/42
    stderr : stderr/42
    ...
    command : myjob

the stdin file will exists as soon as the job is submitted and the others
will exist once the job has begun running.  note that these paths are
shown relative to the queue.  in this case the actual paths would be

  /path/to/q/stdin/42
  /path/to/q/stdout/42
  /path/to/q/stderr/42

but, since our queue is nfs mounted the /path/to/q may or may not be the
same on every host.  thus the path is a relative one.  this can make it
anoying to view these files, but rq assists here with the ioview command.
the ioview command spawns an external editor to view all three files.
it's use is quite simple

examples :

  0) view the stdin/stdout/stderr of job id 42

     ~ > rq q ioview 42

by default this will open up all three files in vim.  the editor command
can be specified using the '--editor' option or the ENV var RQ_EDITOR.
the default value is 'vim -R -o' which allows all three files to be opened
in a single window.

stdin, 0 :

dump the stdinput (if any) provided to the job 

examples :

  0)  dump the stdin for jid 42

    ~ > rq q stdin 42

stdout, 1 :

dump the stdoutput (if any) created by the job 

examples :

  0)  dump the stdout for jid 42

    ~ > rq q stdout 42

stderr, 2 :

dump the stderrput (if any) created by the job 

examples :

  0)  dump the stderr for jid 42

    ~ > rq q stderr 42

stdin4 :

show the path used for the stdin of a jid 

examples :

  0) show which file has job 42's stdin

    ~ > rq q stdin4 42

stdout4 :

show the path used for the stdout of a jid 

examples :

  0) show which file has job 42's stdout

    ~ > rq q stdout4 42

stderr4 :

show the path used for the stderr of a jid 

examples :

  0) show which file has job 42's stderr

    ~ > rq q stderr4 42

recover :

it is possible that a hardware failure might corrupt an rq database.  this
isn't the kind of thing people like hearing, but it's true - hardware has
errors.  in these situations a database can sometimes be readable, but not
writable, or some other combination.  this has been reported only a
handful of times, nevertheless, this command wraps sqlite recovery to get
you rolling again, it's acceptable to perform recovery on a live rq
database with active feeders

examples :

  0) recover!

    ~ > rq q recover

help, h :

this message

examples :

  0) get this message

    ~> rq q help

    or

    ~> rq help

NOTES

  • realize that your job is going to be running on a remote host and this has implications. paths, for example, should be absolute, not relative. specifically the submitted job script must be visible from all hosts currently feeding from a queue as must be the input and output files/directories.

  • jobs are currently run under the bash shell using the --login option. therefore any settings in your .bashrc will apply - specifically your PATH setting. you should not, however, rely on jobs running with any given environment.

  • you need to consider CAREFULLY what the ramifications of having multiple instances of your program all potentially running at the same time will be. for instance, it is beyond the scope of rq to ensure multiple instances of a given program will not overwrite each others output files. coordination of programs is left entirely to the user.

  • the list of finished jobs will grow without bound unless you sometimes delete some (all) of them. the reason for this is that rq cannot know when the user has collected the exit_status of a given job, and so keeps this information in the queue forever until instructed to delete it. if you have collected the exit_status of you job(s) it is not an error to then delete that job from the finished list - the information is kept for your informational purposes only. in a production system it would be normal to periodically save, and then delete, all finished jobs.

  • know that it is a VERY bad idea to spawn several dozen process all reading/writing huge output files to a single NFS server. use this paradigm instead

    • copy/move data from global input space to local disk
    • process data
    • move data on local disk to global output space

    this, of course, applies to any nfs processing, not just those jobs submitted to rq

    the vsftp daemon is an excellent utility to have running on hosts in your cluster so anonymous ftp can be used to get/put data between any two hosts.

  • know that nfs locking is very, very easy to break with firewalls put in place by overzealous system administrators. be postive not only that nfs locking works, but that lock recovery server/client crash or reboot works as well. http://nfs.sourceforge.net/ is the place to learn about NFS. my experience thus far is that there are ZERO properly configured NFS installations in the world. please test yours. contact me for a simple script which can assist you. beer donations required as payment.

ENVIRONMENT

RQ_Q: set to the full path of nfs mounted queue

the queue argument to all commands may be omitted if, and only if, the
environment variable 'RQ_Q' contains the full path to the q.  eg.

  ~ > export RQ_Q=/full/path/to/my/q

this feature can save a considerable amount of typing for those weak of
wrist.  

a shell script like this can also be used to avoid needing to type the
queue name each and every time

  ~ > cat my_q
    #!/bin/sh
    rq /full/path/to/my/q "$@"

and then all operations become, for example

  ~> my_q submit my_mob
  ~> my_q status 
  ~> my_q delete 42

RQ_OPTS | RQ_OPTIONS: specify extra options

this ENV var can be used to specify options which should always apply, for
example

  ~ > export RQ_OPTS=--restartable

and shell script like this might be used to mark jobs submitted by a
certain user and to always submit them at a negative priority

  ~ > cat username_q
    #!/bin/sh
    export RQ_OPTS="--tag=username --priority=-42"
    rq /full/path/to/my/q "$@"

actual command line options wil always override options given this way

DIAGNOSTICS

success : $? == 0 failure : $? != 0

URIS

https://github.com/pjotrp/rq - main website
http://www.linuxjournal.com/article/7922
http://rubyforge.org/projects/codeforpeople/ (original)

LICENSE

rq is distributed under the BSD license, see the ./LICENSE file

CREDITS

  • kim baugh : patient tester and design input
  • jeff safran : the guy can break anything
  • chris elvidge : boss who made it possible
  • trond myklebust : tons of help with nfs
  • jamis buck : for writing the sqlite bindings for ruby
  • _why : for writing yaml for ruby
  • matz : for writing ruby

INSTALL

gem install rq-ruby1.9 (see also top of page)

TEST

Install rq and

test_rq.rb

AUTHOR

Ara Howard ara.t.howard@gmail.com and Pjotr Prins pjotr.public01@thebird.nl

BUGS

0 < bugno && bugno <= 42

reports on github, or to Pjotr Prins pjotr.public01@thebird.nl and Ara Howard ara.t.howard@gmail.com

SEE ALSO

https://github.com/pjotrp/rq - main website

OPTIONS --priority=priority, -p modes : set the job(s) priority - lowest(0) .. highest(n) - (default 0) --tag=tag, -t modes : set the job(s) user data tag --runner=runner modes : set the job(s) required runner(s) --restartable modes : set the job(s) to be restartable on node reboot --stage modes : set the job(s) initial state to be holding (default pending) --infile=infile, -i modes : infile --stdin=[stdin], -s modes : stdin --data=data, -d modes : data --quiet, -q modes : do not echo submitted jobs, fail silently if another process is already feeding --daemon, -D modes : spawn a daemon --max_feed=max_feed modes : the maximum number of concurrent jobs run --retries=retries modes : specify transaction retries --min_sleep=min_sleep modes : specify min sleep --max_sleep=max_sleep modes : specify max sleep --loops=loops, -L modes : specify how many times to loop (default forever) --exit=exit_code_map modes : specify and exit code map --fields=fields, -f limit which fields of output to display --snapshot, -s operate on snapshot of queue --editor=editor, -e editor command capable of opening multiple files at once = (default ENV["RQ_EDITOR"] || "vim -R -o") --verbosity=[verbostiy], -v 0|fatal < 1|error < 2|warn < 3|info < 4|debug - (default info) --log=path, -l set log file - (default stderr) --log_age=log_age daily | weekly | monthly - what age will cause log rolling (default nil) --log_size=log_size size in bytes - what size will cause log rolling (default nil) --dot_rq_dir=[dot_rq_dir] base dir for log/pidfile storage (default ~/.rq/full/path/to/queue) --help, -h this message --version show version number