GenRetry is an Elixir library that provides configurable retry with exponential backoff for any function that raises an exception when it fails.

1. GenRetry
if at first you don't succeed
pete gamache // ElixirConf 2016 // @gamache

2. 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

3. • Your code is perfect
Works first time, every time
• I am not you

4. (my code)

5. J/K, your code fails too
• Failures happen
• Minimizing failures is nice
• Handling failures is even nicer
• Primary weapon: repetition

6. 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

7. 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

8. Background Process

10. GenRetry.retry

11. Task.async

13. GenRetry.Task.async

14. In conclusion
• Let it crash -- on your terms
• Check out our other tools!
https://github.com/appcues/

15. Thanks!