PVC
Pipe between processes as easily as in the shell (currently only on platforms with IO.pipe).
Install it
gem install pvc
Check out the code
git clone git://github.com/chrisberkhout/pvc.git && pvc
bundle install
bundle exec rspec spec
Build the RubyGem yourself
If you like, you can build and install it by running:
gem build pvc.gemspec
gem install pvc-*.gem
Synopsis - implemented
# Run a single process
PVC.new("echo", "hello").run
# Or pipe from one process to another
PVC.new("echo", "hello").to(*%w{tr h H}).run
# Get individual or several outputs from the final result
PVC.new("bash", "-c", "echo hello && ls doesnotexist").run.stdout # => "hello\n"
PVC.new("bash", "-c", "echo hello && ls doesnotexist").run.stderr # => "ls: doesnotexist: No such file or directory\n"
PVC.new("bash", "-c", "echo hello && ls doesnotexist").run.stdboth # => "hello\nls: doesnotexist: No such file or directory\n"
PVC.new("bash", "-c", "echo hello && ls doesnotexist").run.code # => 1
stderr, code = PVC.new("bash", "-c", "echo hello && ls doesnotexist").run.get(:stderr, :code) # => ["ls: doesnotexist: No such file or directory\n", 1]
# Input a string into stdin
PVC.new.input("one\ntwo\nthree\n").to("sort", "-r").run.stdout # => "two\nthree\none\n"
# Process intermediate results with Ruby
PVC.new("cat", "some.log").to { |i,o| i.each_line { |line| o.puts line if line.match(/ERROR/) } }.to("tail", "-n10").run
# Mix stderr and stdin at some point in a pipeline
PVC.new("bash", "-c", "echo hello && ls doesnotexist").with_err.to("wc", "-l").run.stdout # => " 2\n"
# Pass on only stderr at some point in a pipeline
PVC.new("bash", "-c", "echo hello && ls doesnotexist").only_err.to("wc", "-l").run.stdout # => " 1\n"
# Insert one pipeline into another
upcase_unique_pipeline = PVC.new("tr", "a-z", "A-Z").to("uniq")
PVC.new.input("hello\nHeLlO\nworld\nWoRlD\n").to(upcase_unique_pipeline).to("sort", "-r").run.stdout # => "WORLD\nHELLO"
# Shorthand for linewise rewriting
PVC.new.input("hello\nworld").lines_map { |l| l.upcase }.run.stdout "HELLO\nWORLD"
# Shorthand for linewise processing (without modifying the stream)
count = 0
result = PVC.new.input("hello\nworld").lines_tap { |l| count += 1 }.run
count # => 2
result.stdout # => "hello\nworld"
Synopsis - unimplemented
# Kill run if it does not finish in time (miliseconds)
PVC.new("sleep", "2").run(:timeout => 1000)
Compatibility
Tested on Ruby 1.9.3 and 2.1.1.
Copyright
The MIT License
Copyright (C) 2013 by Chris Berkhout (http://chrisberkhout.com)
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.