Added weather route and embedded cache system

types/cache.go

@@ -0,0 +1,66 @@
+package types
+
+import (
+	"time"
+)
+
+// CacheType, representing the abstract value of a CacheEntity
+type CacheType interface {
+	Weather | Metrics
+}
+
+// CacheEntity, representing the value of the cache
+type CacheEntity[T CacheType] struct {
+	Element   T
+	Timestamp time.Time
+}
+
+// Cache, representing a mapping between a key(str) and a CacheEntity
+type Cache[T CacheType] struct {
+	Data map[string]CacheEntity[T]
+}
+
+// Caches, representing a grouping of the various caches
+type Caches struct {
+	WeatherCache Cache[Weather]
+	MetricsCache Cache[Metrics]
+}
+
+func InitCache() *Caches {
+	return &Caches{
+		WeatherCache: Cache[Weather]{Data: make(map[string]CacheEntity[Weather])},
+		MetricsCache: Cache[Metrics]{Data: make(map[string]CacheEntity[Metrics])},
+	}
+}
+
+func (cache *Cache[T]) GetCache(key string, ttl int8) (T, bool) {
+	val, isPresent := cache.Data[key+"_weather"]
+
+	// If key is not present, return a zero value
+	if !isPresent {
+		return val.Element, false
+	}
+
+	// Otherwise check whether cache element is expired
+	currentTime := time.Now()
+	expired := currentTime.Sub(val.Timestamp) > (time.Duration(ttl) * time.Hour)
+	if expired {
+		return val.Element, false
+	}
+
+	return val.Element, true
+}
+
+func (cache *Cache[T]) AddEntry(entry T, cityName string) {
+	currentTime := time.Now()
+
+	switch any(entry).(type) {
+	case Weather:
+		{
+			cache.Data[cityName+"_weather"] = CacheEntity[T]{
+				Element:   entry,
+				Timestamp: currentTime,
+			}
+		}
+	}
+}