geocache 
geocache is an in-memory cache that is suitable for geolocation based applications. It uses geolocation as a key for storing items. You can specify range on initialization and thats it! You can store any object, it uses interface.
Installation
go get github.com/melihmucuk/geocache
Usage
import (
"fmt"
"time"
"github.com/melihmucuk/geocache"
)
func main() {
c, err := geocache.NewCache(5*time.Minute, 30*time.Second, geocache.WithIn1KM)
geoPoint := geocache.GeoPoint{Latitude: 40.9887, Longitude: 28.7817}
if err != nil {
fmt.Println("Error: ", err.Error())
} else {
c.Set(geoPoint, "helloooo", 2*time.Minute)
v1, ok1 := c.Get(geocache.GeoPoint{Latitude: 41.2, Longitude: 29.3})
v2, ok2 := c.Get(geocache.GeoPoint{Latitude: 41.2142, Longitude: 29.4234})
v3, ok3 := c.Get(geocache.GeoPoint{Latitude: 40.9858, Longitude: 28.7852})
v4, ok4 := c.Get(geocache.GeoPoint{Latitude: 40.9827, Longitude: 28.7883})
fmt.Println(v1, ok1)
fmt.Println(v2, ok2)
fmt.Println(v3, ok3)
fmt.Println(v4, ok4)
}
}
outputs:
<nil>, false
<nil>, false
helloooo, true
helloooo, true
Information
You can specify 8 different range. More info can be found here.
WithIn11KM
The first decimal place is worth up to 11.1 km eg: 41.3, 29.6
WithIn1KM
The second decimal place is worth up to 1.1 km eg: 41.36, 29.63
WithIn110M
The third decimal place is worth up to 110 m eg: 41.367, 29.631
WithIn11M
The fourth decimal place is worth up to 11 m eg: 41.3674, 29.6316
WithIn1M
The fifth decimal place is worth up to 1.1 m eg: 41.36742, 29.63168
WithIn11CM
The sixth decimal place is worth up to 0.11 m eg: 41.367421, 29.631689
WithIn11MM
The seventh decimal place is worth up to 11 mm eg: 41.3674211, 29.6316893
WithIn1MM
The eighth decimal place is worth up to 1.1 mm eg: 41.36742115, 29.63168932