Local Cache

In this section, you will learn how to use the local cache to store data in the application's memory.

First, we need to configure the data pools and engine. In this example, we will create two pools: default, without any limit, and test, which can hold up to 100 elements:

import fluxaorm "github.com/latolukasz/fluxaorm/v2"

registry := fluxaorm.NewRegistry()
registry.RegisterLocalCache(fluxaorm.DefaultPoolCode, 0)
registry.RegisterLocalCache("test", 100)
engine, err := registry.Validate()
if err != nil {
    panic(err)
}
ctx := engine.NewContext(context.Background())

When limit is 0, the cache has no size limit and will grow unbounded. When limit is greater than 0, the cache uses an LRU (Least Recently Used) eviction policy -- once the limit is reached, the least recently used entry is evicted to make room for a new one.

Accessing the Local Cache Data Pool

Access the local cache through the engine:

cache := engine.LocalCache(fluxaorm.DefaultPoolCode)
config := cache.GetConfig()
config.GetCode()  // "default"
config.GetLimit() // 0

cache = engine.LocalCache("test")
config = cache.GetConfig()
config.GetCode()  // "test"
config.GetLimit() // 100

LocalCache Interface

The LocalCache interface provides the following public methods:

Retrieving a Value

Use the Get() method to retrieve a single value from the local cache:

cache := engine.LocalCache(fluxaorm.DefaultPoolCode)
value, found := cache.Get(ctx, "test-key")
if found {
    fmt.Printf("Found: %v\n", value)
} else {
    fmt.Println("Not found")
}

Storing a Value

Use the Set() method to store a value in the local cache. The value can be of any type:

cache := engine.LocalCache(fluxaorm.DefaultPoolCode)
cache.Set(ctx, "test-key", "my value")

cache = engine.LocalCache("test")
cache.Set(ctx, "another-key", &SomeStruct{Field: "hello"})

When using a cache with a limit, if the cache is full, the least recently used entry is automatically evicted.

Removing a Value

Use the Remove() method to remove a value from the local cache:

cache.Remove(ctx, "key1")

Clearing the Cache

Use the Clear() method to remove all values from the local cache:

cache.Clear(ctx)

Cache Usage Statistics

Use the GetUsage() method to inspect the current state of the cache. It returns a slice of LocalCacheUsage structs:

cache := engine.LocalCache("test")
usages := cache.GetUsage()
for _, usage := range usages {
    fmt.Printf("Type: %s, Used: %d, Limit: %d, Evictions: %d\n",
        usage.Type, usage.Used, usage.Limit, usage.Evictions)
}

The LocalCacheUsage struct contains:

For a global (non-entity) local cache, GetUsage() returns a single entry with Type set to "Global". For entity-bound caches, it returns separate entries for entities and each list reference.