feat: Add support for on-disk and in-memory caches with configurable duration

internal/cache/cache.go

@@ -0,0 +1,32 @@
+package cache
+
+import (
+	"os"
+	"time"
+
+	"github.com/pojntfx/stfs/pkg/config"
+	"github.com/spf13/afero"
+)
+
+func Cache(
+	base afero.Fs,
+	root string,
+	cacheType string,
+	ttl time.Duration,
+	cacheDir string,
+) (afero.Fs, error) {
+	switch cacheType {
+	case CacheTypeMemory:
+		return afero.NewCacheOnReadFs(afero.NewBasePathFs(base, root), afero.NewMemMapFs(), ttl), nil
+	case CacheTypeDir:
+		if err := os.MkdirAll(cacheDir, os.ModePerm); err != nil {
+			return nil, err
+		}
+
+		return afero.NewCacheOnReadFs(afero.NewBasePathFs(base, root), afero.NewBasePathFs(afero.NewOsFs(), cacheDir), ttl), nil
+	case config.NoneKey:
+		return afero.NewBasePathFs(base, root), nil
+	default:
+		return nil, ErrCacheTypeUnsupported
+	}
+}

internal/cache/check.go

@@ -0,0 +1,17 @@
+package cache
+
+func CheckCacheType(cacheType string) error {
+	cacheTypeIsKnown := false
+
+	for _, candidate := range KnownCacheTypes {
+		if cacheType == candidate {
+			cacheTypeIsKnown = true
+		}
+	}
+
+	if !cacheTypeIsKnown {
+		return ErrCacheTypeUnknown
+	}
+
+	return nil
+}

internal/cache/constants.go

@@ -0,0 +1,14 @@
+package cache
+
+import (
+	"github.com/pojntfx/stfs/pkg/config"
+)
+
+const (
+	CacheTypeMemory = "memory"
+	CacheTypeDir    = "dir"
+)
+
+var (
+	KnownCacheTypes = []string{config.NoneKey, CacheTypeMemory, CacheTypeDir}
+)

internal/cache/errors.go

@@ -0,0 +1,8 @@
+package cache
+
+import "errors"
+
+var (
+	ErrCacheTypeUnsupported = errors.New("cache type unsupported")
+	ErrCacheTypeUnknown     = errors.New("cache type unknown")
+)