Add instance cache

Signed-off-by: Gabriel Adrian Samfira <gsamfira@cloudbasesolutions.com>

cache/instance_cache.go

@@ -0,0 +1,107 @@
+package cache
+
+import (
+	"sync"
+
+	"github.com/cloudbase/garm/params"
+)
+
+var instanceCache *InstanceCache
+
+func init() {
+	cache := &InstanceCache{
+		cache: make(map[string]params.Instance),
+	}
+	instanceCache = cache
+}
+
+type InstanceCache struct {
+	mux sync.Mutex
+
+	cache map[string]params.Instance
+}
+
+func (i *InstanceCache) SetInstance(instance params.Instance) {
+	i.mux.Lock()
+	defer i.mux.Unlock()
+
+	i.cache[instance.ID] = instance
+}
+
+func (i *InstanceCache) GetInstance(id string) (params.Instance, bool) {
+	i.mux.Lock()
+	defer i.mux.Unlock()
+
+	if instance, ok := i.cache[id]; ok {
+		return instance, true
+	}
+	return params.Instance{}, false
+}
+
+func (i *InstanceCache) DeleteInstance(id string) {
+	i.mux.Lock()
+	defer i.mux.Unlock()
+
+	delete(i.cache, id)
+}
+
+func (i *InstanceCache) GetAllInstances() []params.Instance {
+	i.mux.Lock()
+	defer i.mux.Unlock()
+
+	instances := make([]params.Instance, 0, len(i.cache))
+	for _, instance := range i.cache {
+		instances = append(instances, instance)
+	}
+	return instances
+}
+
+func (i *InstanceCache) GetInstancesForPool(poolID string) []params.Instance {
+	i.mux.Lock()
+	defer i.mux.Unlock()
+
+	var filteredInstances []params.Instance
+	for _, instance := range i.cache {
+		if instance.PoolID == poolID {
+			filteredInstances = append(filteredInstances, instance)
+		}
+	}
+	return filteredInstances
+}
+
+func (i *InstanceCache) GetInstancesForScaleSet(scaleSetID uint) []params.Instance {
+	i.mux.Lock()
+	defer i.mux.Unlock()
+
+	var filteredInstances []params.Instance
+	for _, instance := range i.cache {
+		if instance.ScaleSetID == scaleSetID {
+			filteredInstances = append(filteredInstances, instance)
+		}
+	}
+	return filteredInstances
+}
+
+func SetInstanceCache(instance params.Instance) {
+	instanceCache.SetInstance(instance)
+}
+
+func GetInstanceCache(id string) (params.Instance, bool) {
+	return instanceCache.GetInstance(id)
+}
+
+func DeleteInstanceCache(id string) {
+	instanceCache.DeleteInstance(id)
+}
+
+func GetAllInstancesCache() []params.Instance {
+	return instanceCache.GetAllInstances()
+}
+
+func GetInstancesForPool(poolID string) []params.Instance {
+	return instanceCache.GetInstancesForPool(poolID)
+}
+
+func GetInstancesForScaleSet(scaleSetID uint) []params.Instance {
+	return instanceCache.GetInstancesForScaleSet(scaleSetID)
+}