Adding app/cache/memory_store.go

app/cache/memory_store.go

@@ -0,0 +1,55 @@
+package cache
+
+import (
+	"fmt"
+	"reflect"
+	"time"
+)
+
+var now = time.Now
+
+type memoryStoreItem struct {
+	value   any
+	expired time.Time
+}
+
+type MemoryStore struct {
+	data map[string]memoryStoreItem
+}
+
+func NewMemoryStore() *MemoryStore {
+	return &MemoryStore{make(map[string]memoryStoreItem)}
+}
+
+func (s *MemoryStore) Get(key string, value any) error {
+	if item, ok := s.data[key]; ok {
+
+		if item.expired.Before(now()) {
+			delete(s.data, key)
+			return fmt.Errorf("key: %s does not exist", key)
+		}
+
+		v := reflect.ValueOf(value)
+		if v.Kind() != reflect.Pointer {
+			return fmt.Errorf("value must be of pointer type, '%s' passed", v.Kind().String())
+		}
+
+		v.Elem().Set(reflect.ValueOf(item.value))
+
+		return nil
+	}
+	return fmt.Errorf("key: %s does not exist", key)
+}
+
+func (s *MemoryStore) Has(key string) bool {
+	_, hit := s.data[key]
+	return hit
+}
+
+func (s *MemoryStore) Set(key string, value any, ttl time.Duration) error {
+	s.data[key] = memoryStoreItem{
+		value:   value,
+		expired: now().Add(ttl),
+	}
+	return nil
+}

app/cache/memory_store_test.go

@@ -0,0 +1,87 @@
+package cache
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type memoryTestItem struct {
+	String string
+	Num    uint32
+	Float  float32
+}
+
+func TestMemoryStore_Set(t *testing.T) {
+	now = func() time.Time { return time.Unix(1581315270, 0) }
+
+	item := memoryTestItem{
+		String: "MyString",
+		Num:    23,
+		Float:  3.14,
+	}
+
+	expected := map[string]memoryStoreItem{
+		"key1": {
+			value:   item,
+			expired: now().Add(time.Hour),
+		},
+	}
+
+	store := NewMemoryStore()
+	err := store.Set("key1", item, time.Hour)
+	assert.NoError(t, err)
+
+	assert.Equal(t, expected, store.data)
+}
+
+func TestMemoryStore_GetMiss(t *testing.T) {
+	store := NewMemoryStore()
+
+	var v any
+	err := store.Get("Key2", &v)
+	assert.Error(t, err)
+}
+
+func TestMemoryStore_GetHit(t *testing.T) {
+	expected := memoryTestItem{
+		String: "MyString",
+		Num:    23,
+		Float:  3.14,
+	}
+
+	store := NewMemoryStore()
+	err := store.Set("key1", expected, time.Hour)
+	assert.NoError(t, err)
+
+	var actual memoryTestItem
+	err = store.Get("key1", &actual)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, actual)
+}
+
+func TestMemoryStore_GetNonPointer(t *testing.T) {
+	expected := memoryTestItem{
+		String: "MyString",
+		Num:    23,
+		Float:  3.14,
+	}
+
+	store := NewMemoryStore()
+	err := store.Set("key1", expected, time.Hour)
+	assert.NoError(t, err)
+
+	var actual string
+	err = store.Get("key1", actual)
+	assert.EqualError(t, err, "value must be of pointer type, 'string' passed")
+}
+
+func TestMemoryStore_Has(t *testing.T) {
+	store := NewMemoryStore()
+	err := store.Set("key1", "value", time.Hour)
+	assert.NoError(t, err)
+
+	assert.True(t, store.Has("key1"))
+	assert.False(t, store.Has("key2"))
+}