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 1.17.
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.
The system comes with two run wrappers:
bin/run
and
bin/run_with_log
The first provides the most basic functionality, while the second
also captures the stdout and stderr from the invoked job and saves
it to a file in the log directory. You may use either run wrapper.
If you need additional functionality, you can create your own run
wrapper, as long as it preserves the functionality of the default
run_wrapper.
You are encouraged to use run_with_log because of the extra
functionality available to you. If you also use the included web
server to look at the status of today's job, or to browser the logs
from earlier days, clicking on a the status of a job that's already
run will bring up the log file associated with that job. This is
very convenient if you're trying to investigate a job failure.
--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 |
02 |
03 |
04 | $title
05 |
06 |
07 |
08 |
13 |
14 |
24 |
25 |
39 |
40 |
+----------------------------------------------------------------------------------------------------
Lines 01-02 describe the file as an XHTML file. I chose XHTML because
the output can be viewed by any web browser. If you would like another
format, drop me an email.
Line 04 will display the value of the title for that page. The "$" 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.
/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 |
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 | Viewing family $file_name
02 |
03 |
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 |
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 | Viewing job $file_name
02 |
03 |
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 |
02 |
03 | - Family Name
04 | - $family_name
05 | - Job Name
06 | - $name
07 | - Status
08 | - $status
09 | - Return Code
10 | - $rc
11 | - Time Zone
12 | - $tz
13 | - Scheduled Start Time
14 | - $start
15 | - Actual Start Time
16 | - $actual_start
17 | - Stop Time
18 | - $stop
19 |
20 |
02 |
03 | - Family Name
04 | - $family_name
05 | - Job Name
06 | - $name
07 | - Status
08 | - $status
09 | - Return Code
10 | - $rc
11 | - Time Zone
12 | - $tz
13 | - Actual Start Time
14 | - $actual_start_dt
15 | - Stop Time
16 | - $stop_dt
17 |
18 |
Viewing log file $file_name
02 |
03 |
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/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
Allow a user to view the web site
Please make sure you read the section entitled "The Taskforestd Web
Server" for important security considerations.
Having said that, : 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.
Make sure you stop the server and restart it after making any changes to
the configuration file.
Start the web server
To start the web server, run the taskforestd program with the
--config_file and --start options. For example:
taskforestd --config_file=taskforestd.cfg --start
Or, in the case of the ssl version of the server:
taskforestdssl --config_file=taskforestd.cfg --start
Stop the web server
To start the web server, run the taskforestd program with the
--config_file and --stop options. For example:
taskforestd --config_file=taskforestd.cfg --stop
Or, in the case of the ssl version of the server:
taskforestdssl --config_file=taskforestd.cfg --stop
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.
SEE ALSO
perl(1).