NAME

TaskForest - A simple but expressive job scheduler that allows you to chain jobs/tasks and create time dependencies. Uses text config files to specify task dependencies.

VERSION

This version is 1.16.

EXECUTIVE SUMMARY

With the TaskForest Job Scheduler you can:

schedule jobs run at predetermined times
have jobs be dependent on each other
rerun failed jobs
mark jobs as succeeded or failed
check the status of all jobs scheduled to run today
interact with the included web service using your own client code
interact with the included web server using your default browser
express the relationships between jobs using a simple text-based format (a big advantage if you like using 'grep')

SYNOPSIS

# Run the main program, checking for jobs to run.
# By default, this will run until 23:55
#
use TaskForest;
my $task_forest = TaskForest->new();
$task_forest->runMainLoop();

OR

# Display the current status of all jobs scheduled to run today
#
use TaskForest;
my $task_forest = TaskForest->new();
$task_forest->status();

# Rerun job J_RESOLVE in family F_DNS
use TaskForest::Rerun;
rerun("F_DNS", "J_RESOLVE", $log_dir);

# Rerun job J_RESOLVE in family F_DNS
use TaskForest::Rerun;
&TaskForest::Rerun::rerun(
  "F_DNS",            # family name
  "J_RESOLVE",        # job name
  $log_dir,           # log directory
  $cascade,           # optional - apply to all dependent jobs as well
  $dependents_only,   # optional - apply to dependent jobs only
  $family_dir         # family directory
  );


# Mark job J_RESOLVE in family F_DNS as Success
use TaskForest::Mark;
&TaskForest::Mark::mark(
  "F_DNS",            # family name
  "J_RESOLVE",        # job name
  $log_dir,           # log directory
  "Success",          # status
  $cascade,           # optional - apply to all dependent jobs as well
  $dependents_only,   # optional - apply to dependent jobs only
  $family_dir         # family directory
  );

DESCRIPTION

The TaskForest Job Scheduler (TF) is a simple but expressive job scheduling system. A job is defined as any executable program that resides on the file system. Jobs can depend on each other. Jobs can also have start times before which a job may not by run. Jobs can be grouped together into "Families." A family has a start time associated with it before which none of its jobs may run. A family also has a list of days-of-the-week associated with it. Jobs within a family may only run on these days of the week.

Jobs and families are given simple names. A family is described in a family file whose name is the family name. Each family file is a text file that contains 1 or more job names. The layout of the job names within a family file determine the dependencies between the jobs (if any).

Family names and job names should contain only the characters shown below: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_

Let's see a few examples. In these examples the dashes (-), pipes (|) and line numbers are not parts of the files. They're only there for illustration purposes. The main script expects environment variables or command line options that specify the locations of the directory that contain family files, the directory that contains job files, and the directory where the logs will be written. The directory that contains family files should contain only family files.

EXAMPLE 1 - Family file named F_ADMIN

   +---------------------------------------------------------------------
01 |start => '02:00', tz => 'America/Chicago', days => 'Mon,Wed,Fri'
02 |
03 | J_ROTATE_LOGS()
04 |
   +---------------------------------------------------------------------

The first line in any family file always contains 3 bits of information about the family: the start time, the time zone, and the days on which this jobs in this family are run.

In this case, this family starts at 2:00 a.m. Chicago time. The time is adjusted for daylight savings time. This family 'runs' on Monday, Wednesday and Friday only. Pay attention to the format: it's important.

Valid days are 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'. Days must be separated by commas.

All start times (for families and jobs) are in 24-hour format. '00:00' is midnight, '12:00' is noon, '13:00' is 1:00 p.m. and '23:59' is one minute before midnight.

There is only one job in this family - J_ROTATE_LOGS. This family will start at 2:00 a.m., at which time J_ROTATE_LOGS will immediately be run. Note the empty parentheses [()]. These are required.

What does it mean to say that J_ROTATE_LOGS will be run? It means that the system will look for a file called J_ROTATE_LOGS in the directory that contains job files. That file should be executable. The system will execute that file (run that job) and keep track of whether it succeeded or failed. The J_ROTATE_LOGS script can be any executable file: a shell script, a perl script, a C program etc.

To run the program, the system actually runs a wrapper script that invokes the job script. The location of the wrapper script is specified on the command line or in an environment variable.

Now, let's look at a slightly more complicated example:

EXAMPLE 2 - Job Dependencies

This family file is named WEB_ADMIN

   +---------------------------------------------------------------------
01 |start => '02:00', tz => 'America/Chicago', days => 'Mon,Wed,Fri'
02 |
03 |               J_ROTATE_LOGS()
04 |
05 | J_RESOLVE_DNS()               Delete_Logs_Older_Than_A_Year()
06 |
07 |               J_WEB_REPORTS()      
08 |
09 |            J_EMAIL_WEB_RPT_DONE()  # send me a notification
10 |
   +---------------------------------------------------------------------

A few things to point out here:

Blank lines are ignored.
A hash (#) and anything after it, until the end of the line is treated as a comment and ignored
Job and family names do not have to start with J_ or be in upper case.

Now then, all jobs on a single line are started AT THE SAME TIME. All jobs on a line are started only when all jobs on the previous line are executed successfully. If there are no jobs on a previous line (as in the case of line 3 above), all jobs on that line are started when the family starts (2:00 a.m. above). There is an exception to this rule that we'll see in the next example.

So the above family can be interpreted in English as follows: "All WEB_ADMIN jobs are eligible to run after 2:00 a.m Chicago time on Mondays, Wedesdays and Fridays. The first job to be run is J_ROTATE_LOGS. If that succeeds, then J_RESOLVE_DNS and Delete_Logs_Older_Than_A_Year are started at the same time. If both these jobs succeed, then J_WEB_REPORTS is run. If that job succeeds, the J_EMAIL_WEB_RPT_done is run."

EXAMPLE 3 - TIME DEPENDENCIES

Let's say tha twe don't want J_RESOLVE_DNS to start before 9:00 a.m. because it's very IO-intensive and we want to wait until the relatively quiet time of 9:00 a.m. In that case, we can put a time dependency of the job. This adds a restriction to the job, saying that it may not run before the time specified. We would do this as follows:

   +---------------------------------------------------------------------
01 |start => '02:00', tz => 'America/Chicago', days => 'Mon,Wed,Fri'
02 |
03 |               J_ROTATE_LOGS()
04 |
05 | J_RESOLVE_DNS(start => '09:00')    Delete_Logs_Older_Than_A_Year()
06 |
07 |               J_WEB_REPORTS()      
08 |
09 |            J_EMAIL_WEB_RPT_DONE()  # send me a notification
10 |
   +---------------------------------------------------------------------

J_ROTATE_LOGS will still start at 2:00, as always. As soon as it succeeds, Delete_Logs_Older_Than_A_Year is started. If J_ROTATE_LOGS succeeds before 09:00, the system will wait until 09:00 before starting J_RESOLVE_DNS. It is possible that Delete_Logs_Older_Than_A_Year would have started and complete by then. J_WEB_REPORTS would not have started in that case, because it is dependent on two jobs, and both of them have to run successfully before it can run.

For completeness, you may also specify a timezone for a job's time dependency as follows:

05 | J_RESOLVE_DNS(start=>'10:00', tz=>'America/New_York')  Delete_Logs_Older_Than_A_Year()

EXAMPLE 4 - JOB FORESTS

You can see in the example above that line 03 is the start of a group of dependent job. No job on any other line can start unless the job on line 03 succeeds. What if you wanted two or more groups of jobs in the same family that start at the same time (barring any time dependencies) and proceed independently of each other?

To do this you would separate the groups with a line containing one or more dashes (only). Consider the following family:

   +---------------------------------------------------------------------
01 |start => '02:00', tz => 'America/Chicago', days => 'Mon,Wed,Fri'
02 |
03 |               J_ROTATE_LOGS()
04 |
05 | J_RESOLVE_DNS(start => '09:00')    Delete_Logs_Older_Than_A_Year()
06 |
07 |               J_WEB_REPORTS()      
08 |
09 |            J_EMAIL_WEB_RPT_DONE()  # send me a notification
10 |
11 |----------------------------------------------------------------------
12 |
13 | J_UPDATE_ACCOUNTS_RECEIVABLE()
14 |
15 | J_ATTEMPT_CREDIT_CARD_PAYMENTS()
16 |
17 |----------------------------------------------------------------------
18 |
19 | J_SEND_EXPIRING_CARDS_EMAIL()
20 |
   +---------------------------------------------------------------------

Because of the lines of dashes on lines 11 and 17, the jobs on lines 03, 13 and 19 will all start at 02:00. These jobs are independent of each other. J_ATTEMPT_CREDIT_CARD_PAYMENT will not run if J_UPDATE_ACCOUNTS_RECEIVABLE fails. That failure, however will not prevent J_SEND_EXPIRING_CARDS_EMAIL from running.

Finally, you can specify a job to run repeatedly every 'n' minutes, as follows:

   +---------------------------------------------------------------------
01 |start => '02:00', tz => 'America/Chicago', days => 'Mon,Wed,Fri'
02 |
03 | J_CHECK_DISK_USAGE(every=>'30', until=>'23:00')
04 |
   +---------------------------------------------------------------------

This means that J_CHECK_DISK_USAGE will be called every 30 minutes and will not run on or after 23:00. By default, the 'until' time is 23:59. If the job starts at 02:00 and takes 25 minutes to run to completion, the next occurance will still start at 02:30, and not at 02:55. By default, every repeat occurrance will only have one dependency - the time - and will not depend on earlier occurances running successfully or even running at all. If line 03 were:

03 | J_CHECK_DISK_USAGE(every=>'30', until=>'23:00', chained=>1)

...then each repeat job will be dependent on the previous occurance.

USAGE

There are a few simple scripts in the bin directory that simplify usage. To run the program you must let it know where it can find the necessary files and directories. This can be done by environment variables, or via the command line:

export TF_JOB_DIR=/foo/jobs
export TF_LOG_DIR=/foo/logs
export TF_FAMILY_DIR=/foo/families
export TF_RUN_WRAPPER=/foo/bin/run
taskforest

OR

taskforest -run_wrapper=/foo/bin/run \
  --log_dir=/foo/logs \
  --job_dir=/foo/jobs \
  --family_dir=/foo/families

All jobs will run as the user who invoked taskforest.

You can rerun jobs or mark jobs as Success or Failure using the 'rerun' and 'mark' commands as shown below.

OPTIONS

The following command line options are required. If they are not specified on the command line, the environment will be searched for corresponding environment variables.

--run_wrapper=/a/b/r  [or environment variable TF_RUN_WRAPPER]

  This is the location of the run wrapper that is used to execute the
  job files.  The run wrapper is also responsible for creating the
  semaphore files that denote whether a job ran successfully or not.
  You can use the provided run wrapper (bin/run).  If you need more
  functionality, like logging status to a database, you can create
  your own run wrapper, as long as it preserves the functionality of
  the default run_wrapper.   

--log_dir=/a/b/l  [or environment variable TF_LOG_DIR]

  This is called the root log directory.  Every day a dated directory
  named in the form YYYYMMDD will be created and the semaphore files
  will be created in that directory.

--job_dir=/a/b/j  [or environment variable TF_JOB_DIR]

  This is the location of all the job files.  Each job file should be
  an executable file (e.g.: a binary file, a shell script, a perl or
  python script).  The file names are used as job names in the family
  configuration files.  Job names may only contain the characters
  a-z, A-Z, 0-9 and _.  You may create aliases to jobs within this
  directory.

  If a job J1 is present in a family config file, any other
  occurrance of J1 in that family refers TO THAT SAME JOB INSTANCE.
  It does not mean that the job will be run twice.

  If you want the same job running twice, you will have to put it in
  different families, or make soft links to it and have the soft
  link(s) in the family file along with the actual file name.

  If a job is to run repeatedly every x minutes, you could specify
  that using the 'repeat/every' syntax shown above.

--family_dir=/a/b/f  [or environment variable TF_FAMILY_DIR]

  This is the location of all the family files.  As is the case with
  jobs, family names are the file names.  Family names may only
  contain the characters a-z, A-Z, 0-9 and _.

The following command line options are optional

--once_only

  If this option is set, the system will check each family once, run
  any jobs in the Ready state and then exit.  This is useful for
  testing, or if you want to invoke the program via cron or some
  similar system, or if you just want the program to run on demand,
  and not run and sleep all day.

--end_time=HH:MM

  If once_only is not set, this option determines when the main
  program loop should end.  This refers to the local time in 24-hour
  format.  By default it is set to 23:55.  This is the recommended
  maximum.

--wait_time

  This is the amount of seconds to sleep at the end of every
  loop. The default value is 60.

--verbose

  Print a lot of debugging information

--help

  Display help text

--log

  Log stdout and stderr to files

--log_threshold=t

  Log messages at level t and above only will be printed to the
  stdout log file.  The default value is "warn".

--log_file=o

  Messages printed to stdout are saved to file o in the log_directory
  (if --log is set).  The default value is "stdout".

--err_file=e

  Messages printed to stderr are saved to file e in the log_directory
  (if --log is set).  The default value is "stderr".

--config_file=f

  Read configuration settings from config file f.

--chained

  If this is set, all recurring jobs will have the chained attribute
  set to 1 unless specified explicitly in the family file. 

--collapse

  If this option is set then the status command will behave as if the
  --collapse options was specified on the command line.

--ignore_regex=r

  If this option is set then the family files whose names match the
  perl regular expression r will be ignored.  You can specify this
  option more than once on the command line or in the configuration
  file, but if you use the environment to set this option, you can
  only set it to one value.  Look at the included configuration
  file taskforest.cfg for examples.

--default_time_zone

  This is the time zone in which jobs that ran on days in the past will
  be displayed.  When looking at previous days' status, the system has no
  way of knowing what time zone the job was originally scheduled for.
  Therefore, the system will choose the time zone denoted by this
  option.  The default value for this option is "America/Chicago".

DISPLAY STATUS

To get the status of all currently running and recently run jobs, enter the following command:

status

OR

status --log_dir=/foo/logs --family_dir=/foo/families

OR

status --log_dir=/foo/logs --family_dir=/foo/families --collapse

If the --collapse option is used then pending repeat jobs will not be displayed.

The "status" command also accepts a "--date" option, in which case it displays all the jobs that ran for that date. The date must be in the "YYYYMMDD" format:

status --log_dir=/foo/logs --family_dir=/foo/families --date 20090201

If the date specified is not the same as the current date, the "--collapse" option doesn't make any sense, because there can't be any pending jobs for a date in the past.

When displaying the status for days in the past, there is no way for the system to know what time zone the jobs were scheduled for. This is because the corresponding family file could have changed between the time that the job ran and the time that you're running the status command. To resolve this, the system will always display jobs in the time zone specified by the 'default_time_zone' option. If the default time zone is not specified, its default value is "America/Chicago".

RERUN A JOB

To rerun a job, enter the following command:

rerun --log_dir=l_d --job=Ff::Jj

where l_d is the log directory and Ff is the family name and Jj is the job name.

If you run the command like this:

rerun --log_dir=l_d --job=Ff::Jj --cascade --family_dir=f_d

then all the jobs that are directly or indirectly dependent on job Jj in family Ff will also be rerun.

If you run the command like this:

rerun --log_dir=l_d --job=Ff::Jj --dependents_only --family_dir=f_d

then only those jobs that are directly or indirectly dependent on job Jj in family Ff will be rerun. Job Jj will be unaffected.

MARK A JOB SUCCESS OR FAILURE

To mark a previously-run job as success or failure, enter the following command:

mark --log_dir=l_d --job=Ff::Jj --status=s

where l_d is the log directory and Ff is the family name, Jj is the job name, and s is 'Success' or 'Failure'.

If you run the command like this:

mark --log_dir=l_d --job=Ff::Jj --status=s --cascade --family_dir=f_d

then all the jobs that are directly or indirectly dependent on job Jj in family Ff will also be marked.

If you run the command like this:

mark --log_dir=l_d --job=Ff::Jj --status=s --dependents_only --family_dir=f_d

then only those jobs that are directly or indirectly dependent on job Jj in family Ff will be marked. Job Jj will be unaffected.

READING OPTIONS FROM A CONFIG FILE

The 'taskforest' and 'status' commands now accept a "--config_file=f" option. You can now specify commonly used options in the config file, so you do not have to include them on the command line. The config file should contain one option per command line. The following sample config file shows the list of all supported options, and documents their usage.

# ########################################
# SAMPLE CONFIG FILE
# ########################################
# These are the four required command line arguments to taskforest
log_dir         = "t/logs"
family_dir      = "/usr/local/taskforest/families"
job_dir         = "/usr/local/taskforest/jobs"
run_wrapper     = "/usr/local/bin/run"

# wait this many seconds between iterations of the main loop
wait_time       = 60

# stop taskforest at this time of day
end_time        = 2355

# if set to 1, run taskforest once only and exit immediately after that
once_only       = 0

# print out extra logs - may be redundant, due to log_threshold, below
# THIS OPTION WILL BE DEPRECATED SOON.
verbose         = 0

# by default assume that the --collapse option was given to the status command
collapse        = 1  # change from previously default behavior

# by default assume that all repeating jobs have the --chained=>1 attribute set
chained         = 1  # change from previously default behavior

# log stdout and stderr to files
log             = 1

# by default, log stdout messages with status >= this vale.
# This only effects stdout
# The sequence of thresholds (smallest to largest) is:
# debug, info, warn, error, fatal
log_threshold   = "warn"

# The log_file and err_file names should NOT end with '.0' or '.1' 
# because then they will be mistaken for job log files
log_file        = "stdout"  
err_file        = "stderr"  

# currently unused
log_status      = 0

# ignore family files whose names match these regexes
ignore_regex    = "~$"
ignore_regex    = ".bak$"
ignore_regex    = '\$'

PRECEDENCE OF DIFFERENT OPTIONS SOURCES

All settings (required and optional) may be specified in a variety of ways: command line, environment variable and config file. The order of preferences is this: Most options have default values. Settings specified in the config file override those defaults. Settings specified in environment variables take override those specified in the config file and the default values. Setting specified on the command line override those specified in envrionment variables, and those specified in the config files and the default values.

The names of the environment variable are the same as the names of the settings on the command line (or in the config file), but they should be in UPPER CASE, with "TF_" prepended. For example, the environment variable name for the 'run_wrapper' setting is 'TF_RUN_WRAPPER'.

LOGGING STDOUT AND STDERR

If the --log option is set, then anything printed to stdout and stderr will be saved to log files. Before the logging start, the program will print onto stdout the names of the log file and error file. The program logs incidents at different levels ("debug", "info", "warning", "error" and "fatal"). The "log_threshold" option sets the level at which logs are written to the stdout file. If the value of log_threshold is "info", then only those log messages with a level of "info" or above ("warning", "error" or "fatal") will be written to the stdout log file. The stderr log file always has logs printed at level "error" or above, as well as anything printed explicitly to STDERR.

The log file and error file will be saved in the log_directory.

THE TASKFORESTD WEB SERVER

The TaskForest package includes a simple, low-footprint web server, called taskforestd, written in perl. The webserver uses the LWP library and its sole purpose is to give you an web-based interface to TaskForest. I chose to write a perl-based web server because it is easy for users to download, install and deploy. Also it may be too much to ask users to install and mantain Apache, and configure mod_perl, just to get this web-based access.

Taskforestd's behavior is controlled with a configuration file, taskforestd.cfg. This configuration file must be customized as described below, before you can use the web server. Once you have customized the configuration file, you can start web server like this:

taskforestd --config_file=taskforestd.cfg

You can stop the web server like this:

taskforestd --config_file=taskforestd.cfg --stop

For example, if the configuration file specifies that the host on which taskforestd runs is www.example.com, then the web server will be available at http://www.example.com/ .

To use the webserver (or even the web service described below) you must have a valid userid and password. Taskforestd does not ship with any default userid and password pairs. A password is required to authenticate the person making requests via the web browswer. This userid and password combination may be (and should be) different from the userid and password of the account under which taskforestd is running.

Which reminds me, as you would expect, taskforestd runs with the privileges of the account that invoked the program. If that account does not have permissions to read and write the job and family files, you will not be able to use the web server.

It is not a good idea to run taskforestd as root, because even though taskforestd is written with security in mind, running as root opens a huge security hole. And anyway, you shouldn't run as root any program that you download off the 'net any more than you should give a stranger the keys to your house.

The best method is to create a separate system user account for taskforest and taskforestd, and run the web server and command line requests as that user.

Coming back to the taskforestd userid and password: The userids and passwords are specified in the configuration file using the same format as Apache's .htpasswd files. You can see commented-out examples of this in the configuration file taskforestd.cfg. For your convenience, the TaskForest distribution includes a program called gen_passwd that generates text that you can copy and paste into the config file:

gen_passwd foo bar

The above command will print out somthing that looks like the following;

foo:4poVZGiAlO1BY

This text can then be copied and pasted into the configuration file.

Please see the included configuration file, taskforestd.cfg, for a list of each configuration option, and what it means.

Please keep in mind that the taskforestd server is not encrypted. Your userid and password will be transmitted in cleartext. This is a huge security hole. Do not do this unless both the client and the server behind a firewall, for example in a local intranet. If someone sniffs your unencrypted userid and password, they can change job files, family files, or delete them too.

If you wish to use an encrypted, SSL-enabled server, please use the included taskforestdssl program instead of taskforestd. The only difference between the two is that the taskforestd uses HTTP::Daemon, and taskforestdssl uses HTTP::Daemon::SSL. To set up SSL, you will need to set up a server key and a server certificate. The locations of these files may be specified in the taskforestd configuration file, under server_key_file and server_cert file, respctively. You can find more information in the documentation of HTTP::Daemon::SSL.

If you would like to self-sign a certificate, there are some instructions in the HOWTO section later in this document.

If your system does not support SSL (for example, with openssl), and you would like to use taskforestd across the Internet, my advice would be: "Don't." If you do, you would essentially be giving the world the ability to run any command on your server. If you still want to do it, at least make sure that the system account that taskforestd runs under does not have write access to any files, especially those in job_dir, log_dir and family_dir. This means that you would not be able to change job or family files or schedule reruns using taskforestd, but neither would the rest of the world be able to do that on your machine.

A SAMPLE TASKFORESTD CONFIGURATION FILE

# This is a sample taskforestd configuration file

# Please change all settings to values that make sense for you.

# These are the four required command line arguments to taskforest
log_dir         = "t/logs"
family_dir      = "t/families"
job_dir         = "t/jobs"

# This is a file that ensures that only one child process can accept 
# connections at any time
lock_file       = "t/lock_file"

# The HTTP server document_root
document_root   = "htdocs"

# The host on which the taskforest daemon will run
host            = "127.0.0.1"

# The port on which to listen for connections
port            = 1111

# The number of children that should be available at any time
child_count     = 10

# The number of requests each child process should serve before exiting.
# (To protect from memory leaks, etc)
requests_per_child = 40

# Every time a child dies wait this much time (in seconds) before starting 
# a new child. Do NOT set this value to less than 1, otherwise you may
# encounter CPU thrashing.  Set it to something like 10 seconds if you're
# testing.
respawn_wait    = 1

# my default, log stdout messages with status >= this.
# This only effects stdout
# The sequence of thresholds (smallest to largest is):
# debug, info, warn, error, fatal
log_threshold   = "info"

# The log_file and err_file names should NOT end with '.0' or '.1' 
# because then they will be mistaken for job log files
#log_file        = "taskforestd.%Y%m%d.%H%M%S.stdout"  
#err_file        = "taskforestd.%Y%m%d.%H%M%S.stderr"  
log_file        = "taskforestd.stdout"  
err_file        = "taskforestd.stderr"  
pid_file        = "taskforestd.pid"

# Run as a daemon (detach from terminal)
run_as_daemon   = 1

# 
# In order for the web site to work, you must have at least one valid
# user set up.  As the commented examples below show, you may have
# more than one.  The value of each valid_user option is the login
# followed by a colon (:) followed by a crypt hash of the password.
# There are many ways to generate the crypt hash, including using the
# crypt perl function.  You can also use the gen_password script
# included with this release.
#
#valid_user = "test:e3MdYgHPUo.QY"
#valid_user = "foo:jp8Xizm2S52yw"

# The path to the server private key file
server_key_file   = "certs/server-key.pem"

# The path to the server certificate
server_cert_file  = "certs/server-cert.pem"

THE TASKFORESTD RESTFUL WEB SERVICE

The TaskForest package includes a low-footprint web server written in perl. The webserver hosts one or more RESTful Web Services. The web service allows you to write, in any programming language, your own client software that integrates with TaskForest.

For an introduction to RESTful web services, you can look at Wikipedia: http://en.wikipedia.org/wiki/Representational_State_Transfer

A NOTE ABOUT URI NOTATION

For the purposes of this document we will denote variable parts of URIs using braces. For example, in the URI /foo/bar.html/{variable_name} the value of the variable variable_name will replace the string variable_name.

RESTFUL WEB SERVICE VERSION 1.0

All of the service's URIs for version 1.0 are in the /rest/1.0/ hierarchy. If the service upgrades to a newer version, 1.0 will be preserved, and the new service will be in, for example, the /rest/2.0/ hierarchy. This way, backward compatability is preserved while clients migrate to the new interface.

The documentation that follows describes the common 'header' and 'footer' XHTML. This is followed by a list of all the URIs and families of URIs supported by the web service, the HTTP methods that each URI supports, and a description of the service for the client software developer.

HEADERS AND FOOTERS

Every page with an HTTP Status code of 200-207 served by version 1.0 of the web service will start with the html shown below.

   +----------------------------------------------------------------------------------------------------
01 | <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
02 | <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
03 |  <head>
04 |   <title>$title</title>
05 |  </head>
06 |  <body>
07 | 
08 |    <div class="header_navigation">
09 |      <a href="/rest/1.0/familyList.html">Family List</a>
10 |      <a href="/rest/1.0/jobList.html">Job List</a>
11 |      <a href="/rest/1.0/status.html">Status</a>
12 |    </div>
13 | 
14 |    <form id="rerun" class="request" method="POST" action="/rest/1.0/request.html">
15 |      <label for="rerun_family">Family</label><input id="rerun_family" name="family" /><br />
16 |      <label for="rerun_job">Job</label><input id="rerun_job" name="job" /><br />
17 |      <label for="rerun_options">Options</label><select id="rerun_options" name="options">
18 |        <option value="">None</option>
19 |        <option value="cascade">Cascade</option>
20 |        <option value="dependents_only">Dependents Only</option>
21 |      </select>
22 |      <input type=submit name=submit  value="Rerun"/>
23 |    </form>
24 | 
25 |    <form id="mark" class="request" method="POST" action="/rest/1.0/request.html">
26 |      <label for="mark_family">Family</label><input id="mark_family" name="family" /><br />
27 |      <label for="mark_job">Job</label><input id="mark_job" name="job" /><br />
28 |      <label for="mark_options">Options</label><select id="mark_options" name="options">
29 |        <option value="">None</option>
30 |        <option value="cascade">Cascade</option>
31 |        <option value="dependents_only">Dependents Only</option>
32 |      </select>
33 |      <label for="mark_status">Status</label><select id="mark_status" name="status">
34 |        <option value="Success">Success</option>
35 |        <option value="Failure">Failure</option>
36 |      </select>
37 |      <input type=submit name=submit  value="Mark"/>
38 |    </form>
39 | 
40 |    <form id="logs" class="request" method="GET" action="/rest/1.0/logs.html">
41 |      <label for="logs_date">Date</label><input id="logs_date" name="date" size=8 maxlength=8/><br />
42 |      <input type=submit name=submit  value="View Logs"/>
43 |    </form>
   +----------------------------------------------------------------------------------------------------

Lines 01-02 describe the file as an XHTML file. I chose XHTML because the output can be viewed by any web browser. If you would like another format, drop me an email.

Line 04 will display the value of the title for that page. The $ sign is an artifact of the web development framework I'm using.

Lines 08-12 are the main navigation hyperlinks.

Lines 14-23 and 25-38 are the two forms that show up on every page. These forms allow you to rerun jobs, and mark jobs, respectively. They're essentially interfaces to the 'rerun' and 'mark' commands.

Every page with an HTTP Status code of 200-207 served by version 1.0 of the web service will end with the html shown below.

 </body>
</html>

/rest/1.0/familyList.html

HEAD
====
      This URI does not support this method.

GET
===
      DESCRIPTION
      ...........
      Use this URI to retrieve a list of all Families.  These are all the
      files in the directory specified by the family_dir option in the
      taskforestd configuration file.

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The client should not send any content to this URI.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In a typical case, the server will send the header and footer, and
      the 'real' content in between.  The content will look like this:

      01 | <ul class=family_list>
      02 |     <li class=family_name><a href="/rest/1.0/families.html/$file_name">$file_name</a></li>
      03 | </ul>

      Line 02 will appear 0 or more times, depending on how many Families
      are present. 

      HTTP STATUS CODES
      .................
      200 - Everything's OK
      304 - The resource has not been modified since the time
            specified in the request If-Modified-Since header,
            OR 
            The calculated Etag of the resource is the same as that
            specified in the request If-None-Match header.
      404 - The resource was not found

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

PUT
===
      This URI does not support this method.

POST
====
      This URI does not support this method.

DELETE
======
      This URI does not support this method.

/rest/1.0/families.html/{family_name}

HEAD
====
      DESCRIPTION
      ...........
      Send this URI the HEAD method to see if the family specified within
      the URI has changed recently.

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The family name is represented by {family_name} and is part
      of the URI.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      The HTTP content is empty.

      HTTP STATUS CODES
      .................
      200 - Everything's OK
      304 - The resource has not been modified since the time
            specified in the request If-Modified-Since header,
            OR 
            The calculated Etag of the resource is the same as that
            specified in the request If-None-Match header.
      404 - The resource was not found

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

GET
===
      DESCRIPTION
      ...........
      Send this URI the GET method to retrieve the contents of the family
      file whose name is specified within the URI. 

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The family name is represented by {family_name} and is part
      of the URI.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In a typical case, the server will send the header and footer, and
      the 'real' content in between.  The content will look like this:

      01 | <div class="family_title">Viewing family $file_name</div>
      02 | <div id="family_contents_div" class="file_contents"><pre>$file_contents</pre></div>
      03 | <form name="family_form" action="/rest/1.0/families.html/$file_name" method="POST">
      04 |   <input type=hidden name="_method" value="PUT">
      05 |   <textarea name="file_contents" rows=20 cols=100>$file_contents</textarea>
      06 |   <br>
      07 |   <input type=submit value="Update Family" name=update />
      08 | </form>

      Line 01 displays the family name.  Line 02 displays the
      contents of the family file in its own div.  Line 03-08 are a
      form that can be used to update the family file.  Note here
      that the method is POST, but there is a form variable called
      "_method" whose value is "PUT".  This is a common idiom in
      RESTful service development because most web browsers only
      support GET and POST.  This is called overloaded POST.  

      With the taskforestd web service, whenever you need to use the
      HEAD, PUT or DELETE methods, you can use POST and define the
      'real' method with the _method form variable.  

      HTTP STATUS CODES
      .................
      200 - Everything's OK
      304 - The resource has not been modified since the time
            specified in the request If-Modified-Since header,
            OR 
            The calculated Etag of the resource is the same as that
            specified in the request If-None-Match header.
      404 - The resource was not found

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

PUT
===
      DESCRIPTION
      ...........
      Send this URI the PUT method to create a new family file or to
      change the contents of an existing family file.   

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      If your client is really using the PUT method, the contents of
      the family file should be sent in the contents of the HTTP
      request.

      If, however, your client is using overloaded POST, then the
      content that you would have sent with the PUT must be in the
      file_contents form variable.  Overloaded POST is explained in
      the description of the GET method, above.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In the typical case, after creating the new family file, or
      changing the contents of the existing family file, the server will
      return the  same contents as in the case of the GET method.  

      HTTP STATUS CODES
      .................
      200 - OK
      400 - The file_contents form variable was missing, in the case of
            Overloaded POST
      500 - The file could not be written - likely a permission issue  

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

POST
====
      This URI does not support this method. 

DELETE
======
      DESCRIPTION
      ...........
      Send this URI the DELETE method to delete the family file named in
      the URI. 

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The family name is represented by {family_name} and is part
      of the URI.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In the case of DELETE, the server will never return any content.  

      HTTP STATUS CODES
      .................
      204 - Delete was successful and the client should not expect any
            content
      500 - The file could not be deleted - likely a permission issue 

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Content-Length
      o Content-Type

/rest/1.0/jobList.html

HEAD
====
      This URI does not support this method.

GET
===
      DESCRIPTION
      ...........
      Use this URI to retrieve a list of all Jobs.  These are all the
      files in the directory specified by the job_dir option in the
      taskforestd configuration file.

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The client should not send any content to this URI.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In a typical case, the server will send the header and footer, and
      the 'real' content in between.  The content will look like this:

      01 | <ul class=job_list>
      02 |     <li class=job_name><a href="/rest/1.0/jobs.html/$file_name">$file_name</a></li>
      03 | </ul>

      Line 02 will appear 0 or more times, depending on how many Jobs
      are present. 

      HTTP STATUS CODES
      .................
      200 - Everything's OK
      304 - The resource has not been modified since the time
            specified in the request If-Modified-Since header,
            OR 
            The calculated Etag of the resource is the same as that
            specified in the request If-None-Match header.
      404 - The resource was not found

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

PUT
===
      This URI does not support this method.

POST
====
      This URI does not support this method.

DELETE
======
      This URI does not support this method.

/rest/1.0/jobs.html/{job_name}

HEAD
====
      DESCRIPTION
      ...........
      Send this URI the HEAD method to see if the job specified within
      the URI has changed recently.

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The job name is represented by {job_name} and is part
      of the URI.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      The HTTP content is empty.

      HTTP STATUS CODES
      .................
      200 - Everything's OK
      304 - The resource has not been modified since the time
            specified in the request If-Modified-Since header,
            OR 
            The calculated Etag of the resource is the same as that
            specified in the request If-None-Match header.
      404 - The resource was not found

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

GET
===
      DESCRIPTION
      ...........
      Send this URI the GET method to retrieve the contents of the job
      file whose name is specified within the URI. 

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The job name is represented by {job_name} and is part
      of the URI.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In a typical case, the server will send the header and footer, and
      the 'real' content in between.  The content will look like this:

      01 | <div class="job_title">Viewing job $file_name</div>
      02 | <div id="job_contents_div" class="file_contents"><pre>$file_contents</pre></div>
      03 | <form name="job_form" action="/rest/1.0/jobs.html/$file_name" method="POST">
      04 |   <input type=hidden name="_method" value="PUT">
      05 |   <textarea name="file_contents" rows=20 cols=100>$file_contents</textarea>
      06 |   <br>
      07 |   <input type=submit value="Update Job" name=update />
      08 | </form>

      Line 01 displays the job name.  Line 02 displays the contents of
      the job file in its own div.  Line 03-08 are a form that can be
      used to update the job file.  Note here that the method is POST,
      but there is a form variable called "_method" whose value is "PUT".
      This is a common idiom in RESTful service development because most
      web browsers only support GET and POST.  This is called overloaded
      POST.

      With the taskforestd web service, whenever you need to use the
      HEAD, PUT or DELETE methods, you can use POST and define the 'real'
      method with the _method form variable.

      HTTP STATUS CODES
      .................
      200 - Everything's OK
      304 - The resource has not been modified since the time
            specified in the request If-Modified-Since header,
            OR 
            The calculated Etag of the resource is the same as that
            specified in the request If-None-Match header.
      404 - The resource was not found

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

PUT
===
      DESCRIPTION
      ...........
      Send this URI the PUT method to create a new job file or to
      change the contents of an existing job file.   

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      If your client is really using the PUT method, the contents of the
      job file should be sent in the contents of the HTTP request.

      If, however, your client is using overloaded POST, then the content
      that you would have sent with the PUT must be in the file_contents
      form variable.  Overloaded POST is explained in the description of
      the GET method, above.

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In the typical case, after creating the new job file, or changing
      the contents of the existing job file, the server will return the
      same contents as in the case of the GET method.

      HTTP STATUS CODES
      .................
      200 - OK
      400 - The file_contents form variable was missing, in the case of
            Overloaded POST
      500 - The file could not be written - likely a permission issue  

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Last-Modified
      o ETag
      o Content-Length
      o Content-Type

POST
====
      This URI does not support this method. 

DELETE
======
      DESCRIPTION
      ...........
      Send this URI the DELETE method to delete the job file named in the
      URI.  

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The job name is represented by {job_name} and is part of the URI. 

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In the case of DELETE, the server will never return any content.  

      HTTP STATUS CODES
      .................
      204 - Delete was successful and the client should not expect any
            content
      500 - The file could not be deleted - likely a permission issue 

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Content-Length
      o Content-Type

/rest/1.0/status.html

HEAD
====
      This URI does not support this method.

GET
===
      DESCRIPTION
      ...........
      Send this URI the GET method to get the status of today's jobs.  

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      None - no additional information is needed. 

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In a typical case, the server will send the header and footer, and
      the 'real' content in between.  The content will look like this:

      01 | <div class=status>
      02 |     <dl class=job>
      03 |       <dt>Family Name</dt>
      04 |       <dd><a href="/rest/1.0/families.html/$family_name">$family_name</a></dd>
      05 |       <dt>Job Name</dt>
      06 |       <dd><a href="/rest/1.0/jobs.html/$base_name">$name</a></dd>
      07 |       <dt>Status</dt>
      08 |       <dd>$status</dd>
      09 |       <dt>Return Code</dt>
      10 |       <dd>$rc</dd>
      11 |       <dt>Time Zone</dt>
      12 |       <dd>$tz</dd>
      13 |       <dt>Scheduled Start Time</dt>
      14 |       <dd>$start</dd>
      15 |       <dt>Actual Start Time</dt>
      16 |       <dd>$actual_start</dd>
      17 |       <dt>Stop Time</dt>
      18 |       <dd>$stop</dd>
      19 |     </dl>
      20 | </div>

      Lines 02-19 will appear 0 or more times, once for every job that
      appears in the output of the status command.  The --collapse option
      is implied in the web service; pending repeat jobs are not
      displayed.        

      HTTP STATUS CODES
      .................
      200 - OK

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Content-Length
      o Content-Type

PUT
===
      This URI does not support this method.

POST
====
      This URI does not support this method.

DELETE
======
      This URI does not support this method.

/rest/1.0/logs.html?date={date}

HEAD
====
      This URI does not support this method.

GET
===
      DESCRIPTION
      ...........
      Send this URI the GET method to browse the log directory for a
      particular date - to see which jobs ran on that day, and when, and
      what the exit codes were.

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      The date is specified as a query parameter.  The date must be in
      the YYYYMMDD format.  If the date is omitted, then the date will
      default to the current date, and jobs with a status of 'Ready' or
      'Waiting' will also be displayed.           

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In a typical case, the server will send the header and footer, and
      the 'real' content in between.  The content will look like this:

      01 | <div class=status>
      02 |     <dl class=job>
      03 |       <dt>Family Name</dt>
      04 |       <dd><a href="/rest/1.0/families.html/$family_name">$family_name</a></dd>
      05 |       <dt>Job Name</dt>
      06 |       <dd><a href="/rest/1.0/jobs.html/$base_name">$name</a></dd>
      07 |       <dt>Status</dt>
      08 |       <dd>$status</dd>
      09 |       <dt>Return Code</dt>
      10 |       <dd>$rc</dd>
      11 |       <dt>Time Zone</dt>
      12 |       <dd>$tz</dd>
      13 |       <dt>Actual Start Time</dt>    
      14 |       <dd>$actual_start_dt</dd>     
      15 |       <dt>Stop Time</dt>            
      16 |       <dd>$stop_dt</dd>             
      17 |     </dl>              
      18 | </div>                  

      Lines 02-17 will appear 0 or more times, once for every job that
      appears in the output of the status command.  

      HTTP STATUS CODES
      .................
      200 - OK

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Content-Length
      o Content-Type

PUT
===
      This URI does not support this method.

POST
====
      This URI does not support this method.

DELETE
======
      This URI does not support this method.

/rest/1.0/request.html

HEAD
====
      This URI does not support this method.

GET
===
      This URI does not support this method.

PUT
===
      This URI does not support this method.

POST
====
      DESCRIPTION
      ...........
      Send a POST to this URI to request a job be marked as success or
      failure, or be rerun.  

      REPRESENTATION SENT BY CLIENT TO SERVER
      .......................................
      There are three required form variables: "family", "job", and
      "submit".  The first is the name of the family, and the second is
      the name of the job.  If the value of the "submit" variable is
      "Rerun", then that job is rerun.  If the value is "Mark", then the
      job will be marked based on the value of the form variable
      "status", which can take a value of "Success" or "Failure".

      In either case, mark or rerun, the optional variable "options" is
      also permitted.  If it has a value, its value can be either
      "cascade" or "dependents_only".  These are treated the same way as
      the command line options to the 'rerun' and 'mark' commands. 

      REPRESENTATION SENT BY SERVER TO CLIENT
      .......................................
      In every case, the server will send the header and footer, and
      the 'real' content in between.  The content will look like this:

      01 | Request accepted.

      HTTP STATUS CODES
      .................
      200 - OK
      500 - The request could not be honored. 

      HTTP RESPONSE HEADERS
      .....................
      o Date
      o Content-Length
      o Content-Type

DELETE
======
      This URI does not support this method.

HOWTO

Run taskforest all day with cron

This is the line I have in my crontab:

02 00 * * * /usr/local/bin/taskforest --config_file=/foo/bar/taskforest.cfg

Create a self-signed certificate with openssl.

This is what works for me (instructions found at http://www.modssl.org/docs/2.8/ssl_faq.html#ToC25 ).

1) Create a server key

  openssl genrsa -des3 -out server.key.en 1024

2) Make a decrypted version of it

  openssl rsa -in server.key.en -out server-key.pem

3) Create a CSR (Certificate Signing Request)

  openssl req -new -key server-key.pem -out server.csr

4) Create a CA Private Key

  openssl genrsa -des3 -out ca.key.en 1024

5) Create a decrypted version of it

  openssl rsa -in ca.key.en -out ca.key

6) Create a 10-yr self-signed CA cert with the CA key

  openssl req -new -x509 -days 3650 -key ca.key -out my-ca.pem

7) Sign the CSR

   sign.sh server.csr

   The sign.sh program can be found in the pkg.contrib/ subdirectory
   of the mod_ssl distribution.  It is not clear whether or not I can
   include that script in this distribution, so for now at least,
   you'll have to use your own copy.  Make sure you specify the
   locations of the files in the taskforestd configuration file.

BUGS

For an up-to-date bug listing and to submit a bug report, please visit our website at http://sourceforge.net/projects/taskforest/

SUPPORT

For support, please visit our website at http://sourceforge.net/projects/taskforest/

AUTHOR

Aijaz A. Ansari http://sourceforge.net/projects/taskforest/

If you're using this program, I would love to hear from you. Please visit our project website and let me know what you think of it.

ACKNOWLEDGEMENTS

Many thanks to the following for their help and support:

SourceForge
Rosco Rouse

I would also like to thank Randal L. Schwartz for teaching the readers of the Feb 1999 issue of Web Techniques how to write a pre-forking web server, the code upon which the TaskForest Web server is built.

COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself - specifically, the Artistic License.

The full text of the license can be found in the LICENSE file included with this module.

	Global
`s`	Focus search bar
`?`	Bring up this help dialog

	GitHub
`g` `p`	Go to pull requests
`g` `i`	go to github issues (only if github is preferred repository)

	POD
`g` `a`	Go to author
`g` `c`	Go to changes
`g` `i`	Go to issues
`g` `d`	Go to dist
`g` `r`	Go to repository/SCM
`g` `s`	Go to source
`g` `b`	Go to file browse

	Search terms
module: (e.g. module:Plugin)
distribution: (e.g. distribution:Dancer auth)
author: (e.g. author:SONGMU Redis)
version: (e.g. version:1.00)

NAME

VERSION

EXECUTIVE SUMMARY

SYNOPSIS

DESCRIPTION

EXAMPLE 1 - Family file named F_ADMIN

EXAMPLE 2 - Job Dependencies

EXAMPLE 3 - TIME DEPENDENCIES

EXAMPLE 4 - JOB FORESTS

USAGE

OPTIONS

DISPLAY STATUS

RERUN A JOB

MARK A JOB SUCCESS OR FAILURE

READING OPTIONS FROM A CONFIG FILE

PRECEDENCE OF DIFFERENT OPTIONS SOURCES

LOGGING STDOUT AND STDERR

THE TASKFORESTD WEB SERVER

A SAMPLE TASKFORESTD CONFIGURATION FILE

THE TASKFORESTD RESTFUL WEB SERVICE

A NOTE ABOUT URI NOTATION

RESTFUL WEB SERVICE VERSION 1.0

HEADERS AND FOOTERS

/rest/1.0/familyList.html

/rest/1.0/families.html/{family_name}

/rest/1.0/jobList.html

/rest/1.0/jobs.html/{job_name}

/rest/1.0/status.html

/rest/1.0/logs.html?date={date}

/rest/1.0/request.html

HOWTO

Run taskforest all day with cron

Create a self-signed certificate with openssl.

BUGS

SUPPORT

AUTHOR

ACKNOWLEDGEMENTS

COPYRIGHT

SEE ALSO

Module Install Instructions