Property to disable fallbacks

[benjchristensen]

Create a property to disable fallbacks so when run() fails the getFallback() method is not attempted.

There are some types of applications (such as offline batch compute) that would rather fail and retry later than get a fallback.

They may however have HystrixCommand implementations in their codebase (part of libraries, transitive dependencies etc) that have fallbacks implemented.

This property will allow turning off fallbacks for the entire app or for specific commands.

[pgrinchenko]

I am not sure how is it different from not implementing fallback at all.

[benjchristensen]

If an application is using libraries with Hystrix commands that have fallbacks implemented but want them disabled this property would allow that.

At Netflix we have lots of HystrixCommands implemented with fallbacks in many libraries used in dozens of applications but some apps - such as those used for offline batch compute jobs - would rather fail and try again later instead of getting a fallback value.

In other words, the commands have fallback implementations for the primary use case of "online" systems needing an answer now, but "offline" systems may want to turn off fallbacks and allow failure and just retry later since there is no user waiting and they don't want to cache a fallback or make a decision based on a fallback.

[pgrinchenko]

OK. I got your point.