GenRetryif at first you don't succeed

pete gamache // ElixirConf 2016 // @gamache

TL;DR

• GenRetry provides retry with exponential backoff for any function that raises an exception when it fails

• Use it, it's easy

• https://github.com/appcues/gen_retry

• Your code is perfectWorks first time, every time

• I am not you

(my code)

J/K, your code fails too

• Failures happen

• Minimizing failures is nice

• Handling failures is even nicer

• Primary weapon: repetition

Exponential Backoff

• Set an initial retry delay

• Every time you retry, double the previous delay

• Examples are everywhere

• Optional: jitter adds a random percentage of delay

GenRetry basics

• GenRetry.retry/2 handles background processes where we don't care about the output -- replaces spawn_link

• GenRetry.Task.async/2 handles future/promise-style tasks where we do care about the output --> replaces Task.async

Background Process

GenRetry.retry

Task.async

GenRetry.Task.async

In conclusion

• Let it crash -- on your terms

• Check out our other tools! https://github.com/appcues/

Thanks!