Tap (Task Application)
tap n. to draw a supply from a resource
A configurable, distributable workflow framework.
Description
Tap allows the construction of workflows that may be defined, configured, and run from the command line. The tasks and joins composing a workflow are easy to test, subclass, and distribute as gems.
Tap provides a standard library of tasks, generators, and test modules to expedite development.
Usage
Tasks are defined as subclasses of Tap::Task.
[lib/goodnight.rb]
require 'tap/task'
# ::task your basic goodnight moon task
# Says goodnight with a configurable message.
class Goodnight < Tap::Task
config :message, 'goodnight' # a goodnight message
def process(name)
"#{} #{name}"
end
end
Tap discovers tasks.
% tap list
task:
dump # dump data
goodnight # your basic goodnight moon task
list # list resources
load # load data
prompt # open a prompt
signal # signal via a task
join:
gate # collects results
join # unsyncrhonized multi-way join
sync # synchronized multi-way join
middleware:
debugger # default debugger
Generates command-line documentation.
% tap goodnight --help Goodnight -- your basic goodnight moon task
Says goodnight with a configurable message.
--------------------------------------------------------------------------------
usage: tap goodnight NAME
configurations:
--message MESSAGE a goodnight message
options:
--help Print this help
--config FILE Specifies a config file
And provides a robust syntax for building both simple and complex workflows. This joins a goodnight task to a dump task in order to print the goodnight message.
% tap goodnight moon -: dump
goodnight moon
% tap goodnight world --message hello -: dump
hello world
Workflows support the use of middleware to wrap the execution of each task, most commonly for logging and/or debugging.
% tap goodnight moon -: dump --/use debugger
21:06:53 0 << ["moon"] (Goodnight)
21:06:53 0 >> "goodnight moon" (Goodnight)
21:06:53 1 << "goodnight moon" (Tap::Tasks::Dump)
goodnight moon
21:06:53 1 >> "goodnight moon" (Tap::Tasks::Dump)
Tap provides a set of test modules to simplify testing of workflows both off and on the command-line (this documentation is tested, for example):
require 'tap/test/unit'
class ShellTestTest < Test::Unit::TestCase
acts_as_shell_test
def test_goodnight_moon
sh_test %q{
% tap load 'goodnight moon' -: dump
goodnight moon
}
end
end
Tasks can be packaged into gems like any other code. Tap automatically finds tasks in gems containing a tap.yml file so that distribution feels normal and unobtrusive.
% tap load/yaml
unresolvable constant: "load/yaml"
% gem install tap-tasks
...
% tap load/yaml "[1, 2, 3]" -: dump/yaml
---
- 1
- 2
- 3
For local tasks that don't need to be distributed, Tap provides declarations a-la Rake. By default any tasks in a tapfile are available for use.
[tapfile]
desc "concat file contents"
task :cat do |config, *files|
files.collect {|file| File.read(file) }.join
end
desc "grep lines"
task :grep, :e => '.' do |config, str|
str.split("\n").grep(/#{config.e}/)
end
% tap cat tapfile -:a grep -e task -:i dump
task :cat do |config, *files|
task :grep, :e => '.' do |config, str|
See the documentation for a greater explanation of the workflow syntax, several common patterns, and the underlying APIs.
Installation
Tap is available as a gem on Gemcutter.
% gem install tap
Info
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