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CoffeeBreak

A gem to handle waiting until a condition is true.

About

By default, CoffeeBreak calls the supplied block every 0.1 seconds while the result of calling the block is falsey. If the block returns a truthy value, that value is returned and program execution resumes. If the block isn't truthy before the default timeout period of 30 seconds, a CoffeeBreak::TimeoutError is raised.

Usage

require 'coffee_break'
include CoffeeBreak::Waiter

Coffee.break.until { 2 + 2 }      # => returns 4
Coffee.break.until { 2 + 2 == 4 } # => returns true
Coffee.break.until { 2 + 2 == 5 } # => raises CoffeeBreak::TimeoutError

The timeout and time between block calls (interval) can be set in two ways:

## Universal default
CoffeeBreak.default_timeout = 5
CoffeeBreak.default_interval = 0.1
## One time setting
Coffee.break(timeout: 5, interval: 0.1).until { foo }

Similarly, you can tell CoffeeBreak to rescue either one class of errors or an array of error classes that the block could raise.

## Universal default
CoffeeBreak.default_rescues = NameError
# or CoffeeBreak.default_rescues = [ArgumentError, NoMethodError]
## One time setting
Coffee.break(rescues: [TypeError, ZeroDivisionError]).until { foo }
# or Coffee.break(rescues: RuntimeError).until { foo }

You can also tell CoffeeBreak not to raise an error on timeout. Instead, the result of calling the block is returned.

## Universal default
CoffeeBreak.default_raise = false
## One time setting
Coffee.break(raise: false).until { falsey } # => returns false or nil

Finally, you can provide a message to be used if your block times out. If a CoffeeBreak::TimeoutError is raised, this will replace the default error message. If a timeout occurs but no error is raised (you set raise to false), the message will print as a warning (otherwise no warning is printed). This is only set in until (not break) and the universal default can't be changed.

## One time setting
Coffee.break.until(message: "foo couldn't bar") { foo.bar }

If you don't want Coffee in your top level namespace or don't like the above syntax, you can use the alternate syntax below. Note that message and the configuration arguments are all passed to until, unlike the above syntax which keeps your configuration and message arguments separate.

CoffeeBreak.until(message: 'No yo', timeout: 5, raise: false) { Yo.yo? }

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to [rubygems.org] (https://rubygems.org).

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/Cohen-Carlisle/coffee_break.

License

The gem is available as open source under the terms of the [MIT License] (http://opensource.org/licenses/MIT).