WithLocking

A gem to execute a block of code and ensure that one does not execute other code until the block has completed executing.

Installation

Add this line to your application's Gemfile:

gem 'with_locking'

Or install it yourself as:

$ gem install with_locking

Usage

A block of code can be executed like so:

WithLocking.run { puts "this code is locked!" }

Alternatively, run the block of code with an optional name (recommended), that way multiple WithLocking blocks with different names can be invoked without conflicting:

WithLocking.run(name: "sleeper") { sleep 60 }
WithLocking.run(name: "sleeper") do 
    puts "I won't execute and will return false because 'sleeper' 
          is still running the first block." 
end
WithLocking.run(name: "other_name") do 
    puts "But I will run because 'other_name' isn't running!"
end
# => "But I will run because 'other_name' isn't running!"

To simply test if a named block is still running without executing a block use the locked? method:

WithLocking.locked?("sleeper")
# => true or false

To raise an exception when the block isn't run (rather than simply returning false), use the do! method:

WithLocking.run!(name: "sleeper") { puts "Blah" }
# => raises an error if 'sleeper' block is still running from before