Description

A thin wrapper for begin + rescue + sleep + retry.

Installation

gem install attempt

Adding the trusted cert

gem cert --add <(curl -Ls https://raw.githubusercontent.com/djberg96/attempt/main/certs/djberg96_pub.pem)

Synopsis

require 'attempt'

# Attempt to ftp to some host, trying 3 times with 30 seconds between
# attempts before finally raising an error.

attempt(tries: 3, interval: 30){
  Net::FTP.open(host, user, passwd){ ... }
}

# Or, do things the long way...
code = Attempt.new do |a|
  a.tries    = 3
  a.interval = 30
end

code.attempt{
  Net::FTP.open(host, user, passwd){ ... }
}

Known Bugs

None that I'm aware of. If you find any bugs, please log them on the project page at:

https://github.com/djberg96/attempt

Caveats

Use with caution. Specifically, make sure you aren't inadvertantly wrapping code that already performs sleep + retry. Otherwise, you'll end up with a series of nested retry's that could take much longer to work than you expect.

Also, this library uses the timeout library internally, which has some known issues. See Future Plans, below.

As of version 0.3.0, this library requires structured_warnings 0.3.0 or later. This is necessary because of changes in Ruby 2.4.

Update: I've switched from the timeout library in the standard library to the safe_timeout library on non-Windows platforms which should improve things. In addition, the structured_warnings library requirement is now 0.4.0 or later in order to work with Ruby 2.7.

Future Plans

Add the ability to set an absolute maximum number of seconds to prevent nested sleep/retry from delaying attempts longer than expected.

Replace the timeout library with a self selecting pipe if possible.

Acknowledgements

This library is partially based on Mark Fowler's 'Attempt' Perl module.

Warranty

This package is provided "as is" and without any express or implied warranties, including, without limitation, the implied warranties of merchantability and fitness for a particular purpose.

License

Apache-2.0

(C) 2006-2022, Daniel J. Berger All Rights Reserved

Author

Daniel J. Berger