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51 lines
1.4 KiB
Markdown
51 lines
1.4 KiB
Markdown
# Retry A Block After An Exception
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Ruby comes with a [_retry_
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mechanism](https://ruby-doc.org/docs/keywords/1.9/Object.html#method-i-retry)
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that allows you to recover from known exceptions by retrying the code that led
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to the exception. In network or timing-based situations where race conditions
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are possible, the most straightforward recourse may be to just _retry_ a couple
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times.
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Set up a `begin` / `rescue` block like you'd normally do for a chunk of code
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that may raise an exception. Then add a `retry` call to the `rescue` block.
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```ruby
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begin
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puts "About to do a thing (#{retries})"
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raise StandardError if rand(5) != 4
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puts "Success!"
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rescue StandardError => e
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retry
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end
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```
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If an exception is raised, this will tell Ruby to re-execute the code in the
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`begin` block over and over until the exception isn't raised.
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To avoid an infinite loop, you can limit the retries with a counting variable.
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```ruby
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begin
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retries ||= 0
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puts "About to do a thing (#{retries})"
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raise StandardError if rand(5) != 4
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puts "Success!"
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rescue StandardError => e
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retry if (retries += 1) < 3
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# all retries failed, re-raise exception
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raise e
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end
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```
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This will re-raise after 3 tries.
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Here is the [full example](https://gist.github.com/jbranchaud/629fb3b9d55c817e5c9fc480790dfabc)
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[source](https://www.honeybadger.io/blog/how-to-try-again-when-exceptions-happen-in-ruby/)
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