Monotime

A sensible interface to Ruby's monotonic clock, inspired by Rust.

Installation

Add this line to your application's Gemfile:

gem 'monotime'

And then execute:

$ bundle

Or install it yourself as:

$ gem install monotime

Usage

The typical way everyone does "correct" elapsed-time measurements in Ruby is this pile of nonsense:

start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
do_something
elapsed = Process.clock_gettime(Process::CLOCK_MONOTONIC) - start

Not only is it long-winded, it's imprecise, converting to floating point instead of working off precise timestamps.

Monotime offers this alternative:

include Monotime

start = Instant.now
do_something
elapsed = start.elapsed

# or
elapsed = Duration.measure { do_something }

elapsed is not a dimensionless Float, but a Duration type, and internally both Instant and Duration operate in nanoseconds to most closely match the native timekeeping types used by most operating systems.

Duration knows how to format itself:

Duration.from_millis(42).to_s       # => "42ms"
Duration.from_nanos(12345).to_s     # => "12.345μs"
Duration.from_secs(1.12345).to_s(2) # => "1.12s"

And how to do basic maths on itself:

(Duration.from_millis(42) + Duration.from_secs(1)).to_s  # => "1.042s"
(Duration.from_millis(42) - Duration.from_secs(-1)).to_s # => "-958ms"

Instant does some simple maths too:

# Instant - Duration => Instant
(Instant.now - Duration.from_secs(1)).elapsed.to_s # => "1.000014627s"

# Instant - Instant => Duration
(Instant.now - Instant.now).to_s                   # => "-5.585μs"

Duration and Instant are also Comparable with other instances of their type, and support #hash for use in, er, hashes.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/Freaky/monotime.

License

The gem is available as open source under the terms of the MIT License.