Issue #59 : Add SetNx (Set if not exist) method to cache

[arjun-kr-tw]

• addressng the issue : On a cache miss, can we provide a function to be called that loads the cache from a source and then return the value? #59

[patrickmn]

Thanks, but looking at the "examples" in the test case, this feels too weird in this language. I don't think the overhead of those type signatures are worth it. There's already too much empty interface and type-assertion overhead in this library.

[krarjun90]

@patrickmn ok i agree the examples in test cases doesn't tell you the real need of this. Let's say you have a function to fetch the data from database and then cache the data for few mins.

So SetNx will help in checking if the data exist, and if not call the function, get the data, set it and return.

[krarjun90]

@patrickmn Also SetNx is something which is available across many libraries.

https://godoc.org/github.com/go-redis/redis#Client.SetNX
https://redis.io/commands/setnx