Kernel#retryable

Description

Runs a code block, and retries it when an exception occurs. It's great when working with flakey webservices (for example).

It's configured using two optional parameters --:tries and :on--, and runs the passed block. Should an exception occur, it'll retry for (n-1) times.

Should the number of retries be reached without success, the last exception will be raised.

Examples

Open an URL, retry up to two times when an OpenURI::HTTPError occurs.

require "retryable"
require "open-uri"

retryable( :tries => 3, :on => OpenURI::HTTPError ) do
  xml = open( "http://example.com/test.xml" ).read
end

Do something, retry up to four times for either ArgumentError or TimeoutError exceptions.

require "retryable"

retryable( :tries => 5, :on => [ ArgumentError, TimeoutError ] ) do
  # some crazy code
end

Defaults

:tries => 1, :on => Exception

Installation

First, make sure GitHub is a gem source. Then, install the gem:

sudo gem install carlo-retryable

Todo

• Unit tests

Changelog

• v1.2: FIX -- block would run twice when :tries was set to 0. (Thanks for the heads-up to Tuker.)

Thanks

Many thanks to Chu Yeow for this nifty piece of code. Look, I liked it enough to enhance it a little bit and build a gem from it! :)