Use go-micro store to cache the roles (#4337)

* Use go-micro store to cache the roles

Add custom in-memory implementation

* replace redis with custom etcd implementation

* adjust table name for the cache in the roles manager

* Fix tests

* Fix sonarcloud issues

* Refactor for sonarcloud

* Allow configuration of cache per service

* Reuse parent context in etcd implementation

ocis-pkg/store/memory/memstore.go

@@ -0,0 +1,513 @@
+package memory
+
+import (
+	"container/list"
+	"context"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/armon/go-radix"
+	"go-micro.dev/v4/store"
+)
+
+// In-memory store implementation using radix tree for fast prefix and suffix
+// searches.
+// Insertions are expected to be a bit slow due to the data structures, but
+// searches are expected to be fast, including exact key search, as well as
+// prefix and suffix searches (based on the number of elements to be returned).
+// Prefix+suffix search isn't optimized and will depend on how many items we
+// need to skip.
+// It's also recommended to use reasonable limits when using prefix or suffix
+// searches because we'll need to traverse the data structures to provide the
+// results. The traversal will stop a soon as we have the required number of
+// results, so it will be faster if we use a short limit.
+//
+// The overall performance will depend on how the radix trees are built.
+// The number of elements won't directly affect the performance but how the
+// keys are dispersed. The more dispersed the keys are, the faster the search
+// will be, regardless of the number of keys. This happens due to the number
+// of hops we need to do to reach the target element.
+// This also mean that if the keys are too similar, the performance might be
+// slower than expected even if the number of elements isn't too big.
+type MemStore struct {
+	preRadix     *radix.Tree
+	sufRadix     *radix.Tree
+	evictionList *list.List
+
+	options store.Options
+
+	lockGlob     sync.RWMutex
+	lockEvicList sync.RWMutex // Read operation will modify the eviction list
+}
+
+type storeRecord struct {
+	Key       string
+	Value     []byte
+	Metadata  map[string]interface{}
+	Expiry    time.Duration
+	ExpiresAt time.Time
+}
+
+type contextKey string
+
+var targetContextKey contextKey
+
+// Prepare a context to be used with the memory implementation. The context
+// is used to set up custom parameters to the specific implementation.
+// In this case, you can configure the maximum capacity for the MemStore
+// implementation as shown below.
+// ```
+// cache := NewMemStore(
+//   store.WithContext(
+//     NewContext(
+//       ctx,
+//       map[string]interface{}{
+//         "maxCap": 50,
+//       },
+//     ),
+//   ),
+// )
+// ```
+//
+// Available options for the MemStore are:
+// * "maxCap" -> 512 (int) The maximum number of elements the cache will hold.
+// Adding additional elements will remove old elements to ensure we aren't over
+// the maximum capacity.
+//
+// For convenience, this can also be used for the MultiMemStore.
+func NewContext(ctx context.Context, storeParams map[string]interface{}) context.Context {
+	return context.WithValue(ctx, targetContextKey, storeParams)
+}
+
+// Create a new MemStore instance
+func NewMemStore(opts ...store.Option) store.Store {
+	m := &MemStore{}
+	_ = m.Init(opts...)
+	return m
+}
+
+// Get the maximum capacity configured. If no maxCap has been configured
+// (via `NewContext`), 512 will be used as maxCap.
+func (m *MemStore) getMaxCap() int {
+	maxCap := 512
+
+	ctx := m.options.Context
+	if ctx == nil {
+		return maxCap
+	}
+
+	ctxValue := ctx.Value(targetContextKey)
+	if ctxValue == nil {
+		return maxCap
+	}
+	additionalOpts := ctxValue.(map[string]interface{})
+
+	confCap, exists := additionalOpts["maxCap"]
+	if exists {
+		maxCap = confCap.(int)
+	}
+	return maxCap
+}
+
+// Initialize the MemStore. If the MemStore was used, this will reset
+// all the internal structures and the new options (passed as parameters)
+// will be used.
+func (m *MemStore) Init(opts ...store.Option) error {
+	optList := store.Options{}
+	for _, opt := range opts {
+		opt(&optList)
+	}
+
+	m.lockGlob.Lock()
+	defer m.lockGlob.Unlock()
+
+	m.preRadix = radix.New()
+	m.sufRadix = radix.New()
+	m.evictionList = list.New()
+	m.options = optList
+
+	return nil
+}
+
+// Get the options being used
+func (m *MemStore) Options() store.Options {
+	m.lockGlob.RLock()
+	defer m.lockGlob.RUnlock()
+
+	return m.options
+}
+
+// Write the record in the MemStore.
+// Note that Database and Table options will be ignored.
+// Expiration options will take the following precedence:
+// TTL option > expiration option > TTL record
+//
+// New elements will take the last position in the eviction list. Updating
+// an element will also move the element to the last position.
+//
+// Although not recommended, new elements might be inserted with an
+// already-expired date
+func (m *MemStore) Write(r *store.Record, opts ...store.WriteOption) error {
+	var element *list.Element
+
+	wopts := store.WriteOptions{}
+	for _, opt := range opts {
+		opt(&wopts)
+	}
+	cRecord := toStoreRecord(r, wopts)
+
+	m.lockGlob.Lock()
+	defer m.lockGlob.Unlock()
+
+	ele, exists := m.preRadix.Get(cRecord.Key)
+	if exists {
+		element = ele.(*list.Element)
+		element.Value = cRecord
+
+		m.evictionList.MoveToBack(element)
+	} else {
+		if m.evictionList.Len() >= m.getMaxCap() {
+			elementToDelete := m.evictionList.Front()
+			if elementToDelete != nil {
+				recordToDelete := elementToDelete.Value.(*storeRecord)
+				_, _ = m.preRadix.Delete(recordToDelete.Key)
+				_, _ = m.sufRadix.Delete(recordToDelete.Key)
+				m.evictionList.Remove(elementToDelete)
+			}
+		}
+		element = m.evictionList.PushBack(cRecord)
+		_, _ = m.preRadix.Insert(cRecord.Key, element)
+		_, _ = m.sufRadix.Insert(reverseString(cRecord.Key), element)
+	}
+	return nil
+}
+
+// Read the key from the MemStore. A list of records will be returned even if
+// you're asking for the exact key (only one record is expected in that case).
+//
+// Reading the exact element will move such element to the last position of
+// the eviction list. This WON'T apply for prefix and / or suffix reads.
+//
+// This method guarantees that no expired element will be returned. For the
+// case of exact read, the element will be removed and a "not found" error
+// will be returned.
+// For prefix and suffix reads, all the elements that we traverse through
+// will be removed. This includes the elements we need to skip as well as
+// the elements that might have gotten into the the result. Note that the
+// elements that are over the limit won't be touched
+//
+// All read options are supported except Database and Table.
+//
+// For prefix and prefix+suffix options, the records will be returned in
+// alphabetical order on the keys.
+// For the suffix option (just suffix, no prefix), the records will be
+// returned in alphabetical order after reversing the keys. This means,
+// reverse all the keys and then sort them alphabetically. This just affects
+// the sorting order; the keys will be returned as expected.
+// This means that ["aboz", "caaz", "ziuz"] will be sorted as ["caaz", "aboz", "ziuz"]
+// for the key "z" as suffix.
+//
+// Note that offset are supported but not recommended. There is no direct access
+// to the record X. We'd need to skip all the records until we reach the specified
+// offset, which could be problematic.
+// Performance for prefix and suffix searches should be good assuming we limit
+// the number of results we need to return.
+func (m *MemStore) Read(key string, opts ...store.ReadOption) ([]*store.Record, error) {
+	var element *list.Element
+
+	ropts := store.ReadOptions{}
+	for _, opt := range opts {
+		opt(&ropts)
+	}
+
+	if !ropts.Prefix && !ropts.Suffix {
+		m.lockGlob.RLock()
+		ele, exists := m.preRadix.Get(key)
+		if !exists {
+			m.lockGlob.RUnlock()
+			return nil, store.ErrNotFound
+		}
+
+		element = ele.(*list.Element)
+		record := element.Value.(*storeRecord)
+		if record.Expiry != 0 && record.ExpiresAt.Before(time.Now()) {
+			// record expired -> need to delete
+			m.lockGlob.RUnlock()
+			m.lockGlob.Lock()
+			defer m.lockGlob.Unlock()
+
+			m.evictionList.Remove(element)
+			_, _ = m.preRadix.Delete(key)
+			_, _ = m.sufRadix.Delete(reverseString(key))
+			return nil, store.ErrNotFound
+		}
+
+		m.lockEvicList.Lock()
+		m.evictionList.MoveToBack(element)
+		m.lockEvicList.Unlock()
+
+		foundRecords := []*store.Record{
+			fromStoreRecord(record),
+		}
+		m.lockGlob.RUnlock()
+
+		return foundRecords, nil
+	}
+
+	records := []*store.Record{}
+	expiredElements := make(map[string]*list.Element)
+
+	m.lockGlob.RLock()
+	if ropts.Prefix && ropts.Suffix {
+		// if we need to check both prefix and suffix, go through the
+		// prefix tree and skip elements without the right suffix. We
+		// don't need to check the suffix tree because the elements
+		// must be in both trees
+		m.preRadix.WalkPrefix(key, m.radixTreeCallBackCheckSuffix(ropts.Offset, ropts.Limit, key, &records, expiredElements))
+	} else {
+		if ropts.Prefix {
+			m.preRadix.WalkPrefix(key, m.radixTreeCallBack(ropts.Offset, ropts.Limit, &records, expiredElements))
+		}
+		if ropts.Suffix {
+			m.sufRadix.WalkPrefix(reverseString(key), m.radixTreeCallBack(ropts.Offset, ropts.Limit, &records, expiredElements))
+		}
+	}
+	m.lockGlob.RUnlock()
+
+	// if there are expired elements, get a write lock and delete the expired elements
+	if len(expiredElements) > 0 {
+		m.lockGlob.Lock()
+		for key, element := range expiredElements {
+			m.evictionList.Remove(element)
+			_, _ = m.preRadix.Delete(key)
+			_, _ = m.sufRadix.Delete(reverseString(key))
+		}
+		m.lockGlob.Unlock()
+	}
+	return records, nil
+}
+
+// Remove the record based on the key. It won't return any error if it's missing
+//
+// Database and Table options aren't supported
+func (m *MemStore) Delete(key string, opts ...store.DeleteOption) error {
+	m.lockGlob.Lock()
+	defer m.lockGlob.Unlock()
+
+	ele, exists := m.preRadix.Get(key)
+	if exists {
+		element := ele.(*list.Element)
+		m.evictionList.Remove(element)
+		_, _ = m.preRadix.Delete(key)
+		_, _ = m.sufRadix.Delete(reverseString(key))
+	}
+	return nil
+}
+
+// List the keys currently used in the MemStore
+//
+// All options are supported except Database and Table
+//
+// For prefix and prefix+suffix options, the keys will be returned in
+// alphabetical order.
+// For the suffix option (just suffix, no prefix), the keys will be
+// returned in alphabetical order after reversing the keys. This means,
+// reverse all the keys and then sort them alphabetically. This just affects
+// the sorting order; the keys will be returned as expected.
+// This means that ["aboz", "caaz", "ziuz"] will be sorted as ["caaz", "aboz", "ziuz"]
+func (m *MemStore) List(opts ...store.ListOption) ([]string, error) {
+	records := []string{}
+	expiredElements := make(map[string]*list.Element)
+
+	lopts := store.ListOptions{}
+	for _, opt := range opts {
+		opt(&lopts)
+	}
+
+	if lopts.Prefix == "" && lopts.Suffix == "" {
+		m.lockGlob.RLock()
+		m.preRadix.Walk(m.radixTreeCallBackKeysOnly(lopts.Offset, lopts.Limit, &records, expiredElements))
+		m.lockGlob.RUnlock()
+
+		// if there are expired elements, get a write lock and delete the expired elements
+		if len(expiredElements) > 0 {
+			m.lockGlob.Lock()
+			for key, element := range expiredElements {
+				m.evictionList.Remove(element)
+				_, _ = m.preRadix.Delete(key)
+				_, _ = m.sufRadix.Delete(reverseString(key))
+			}
+			m.lockGlob.Unlock()
+		}
+		return records, nil
+	}
+
+	m.lockGlob.RLock()
+	if lopts.Prefix != "" && lopts.Suffix != "" {
+		// if we need to check both prefix and suffix, go through the
+		// prefix tree and skip elements without the right suffix. We
+		// don't need to check the suffix tree because the elements
+		// must be in both trees
+		m.preRadix.WalkPrefix(lopts.Prefix, m.radixTreeCallBackKeysOnlyWithSuffix(lopts.Offset, lopts.Limit, lopts.Suffix, &records, expiredElements))
+	} else {
+		if lopts.Prefix != "" {
+			m.preRadix.WalkPrefix(lopts.Prefix, m.radixTreeCallBackKeysOnly(lopts.Offset, lopts.Limit, &records, expiredElements))
+		}
+		if lopts.Suffix != "" {
+			m.sufRadix.WalkPrefix(reverseString(lopts.Suffix), m.radixTreeCallBackKeysOnly(lopts.Offset, lopts.Limit, &records, expiredElements))
+		}
+	}
+	m.lockGlob.RUnlock()
+
+	// if there are expired elements, get a write lock and delete the expired elements
+	if len(expiredElements) > 0 {
+		m.lockGlob.Lock()
+		for key, element := range expiredElements {
+			m.evictionList.Remove(element)
+			_, _ = m.preRadix.Delete(key)
+			_, _ = m.sufRadix.Delete(reverseString(key))
+		}
+		m.lockGlob.Unlock()
+	}
+	return records, nil
+}
+
+func (m *MemStore) Close() error {
+	return nil
+}
+
+func (m *MemStore) String() string {
+	return "RadixMemStore"
+}
+
+func (m *MemStore) Len() (int, bool) {
+	eLen := m.evictionList.Len()
+	pLen := m.preRadix.Len()
+	sLen := m.sufRadix.Len()
+	if eLen == pLen && eLen == sLen {
+		return eLen, true
+	}
+	return 0, false
+}
+
+func (m *MemStore) radixTreeCallBack(offset, limit uint, result *[]*store.Record, expiredElements map[string]*list.Element) radix.WalkFn {
+	currentIndex := new(uint) // needs to be a pointer so the value persist across callback calls
+	maxIndex := new(uint)     // needs to be a pointer so the value persist across callback calls
+	*maxIndex = offset + limit
+	return func(key string, value interface{}) bool {
+		element := value.(*list.Element)
+		record := element.Value.(*storeRecord)
+
+		if record.Expiry != 0 && record.ExpiresAt.Before(time.Now()) {
+			// record has expired -> add element to the expiredElements map
+			// and jump directly to the next element without increasing the index
+			expiredElements[record.Key] = element
+			return false
+		}
+
+		if *currentIndex >= offset && (*currentIndex < *maxIndex || *maxIndex == offset) {
+			// if it's within expected range, add a copy to the results
+			*result = append(*result, fromStoreRecord(record))
+		}
+
+		*currentIndex++
+
+		if *currentIndex < *maxIndex || *maxIndex == offset {
+			return false
+		}
+		return true
+	}
+}
+
+func (m *MemStore) radixTreeCallBackCheckSuffix(offset, limit uint, presuf string, result *[]*store.Record, expiredElements map[string]*list.Element) radix.WalkFn {
+	currentIndex := new(uint) // needs to be a pointer so the value persist across callback calls
+	maxIndex := new(uint)     // needs to be a pointer so the value persist across callback calls
+	*maxIndex = offset + limit
+	return func(key string, value interface{}) bool {
+		if !strings.HasSuffix(key, presuf) {
+			return false
+		}
+
+		element := value.(*list.Element)
+		record := element.Value.(*storeRecord)
+
+		if record.Expiry != 0 && record.ExpiresAt.Before(time.Now()) {
+			// record has expired -> add element to the expiredElements map
+			// and jump directly to the next element without increasing the index
+			expiredElements[record.Key] = element
+			return false
+		}
+
+		if *currentIndex >= offset && (*currentIndex < *maxIndex || *maxIndex == offset) {
+			*result = append(*result, fromStoreRecord(record))
+		}
+
+		*currentIndex++
+
+		if *currentIndex < *maxIndex || *maxIndex == offset {
+			return false
+		}
+		return true
+	}
+}
+
+func (m *MemStore) radixTreeCallBackKeysOnly(offset, limit uint, result *[]string, expiredElements map[string]*list.Element) radix.WalkFn {
+	currentIndex := new(uint) // needs to be a pointer so the value persist across callback calls
+	maxIndex := new(uint)     // needs to be a pointer so the value persist across callback calls
+	*maxIndex = offset + limit
+	return func(key string, value interface{}) bool {
+		element := value.(*list.Element)
+		record := element.Value.(*storeRecord)
+
+		if record.Expiry != 0 && record.ExpiresAt.Before(time.Now()) {
+			// record has expired -> add element to the expiredElements map
+			// and jump directly to the next element without increasing the index
+			expiredElements[record.Key] = element
+			return false
+		}
+
+		if *currentIndex >= offset && (*currentIndex < *maxIndex || *maxIndex == offset) {
+			*result = append(*result, record.Key)
+		}
+
+		*currentIndex++
+
+		if *currentIndex < *maxIndex || *maxIndex == offset {
+			return false
+		}
+		return true
+	}
+}
+
+func (m *MemStore) radixTreeCallBackKeysOnlyWithSuffix(offset, limit uint, presuf string, result *[]string, expiredElements map[string]*list.Element) radix.WalkFn {
+	currentIndex := new(uint) // needs to be a pointer so the value persist across callback calls
+	maxIndex := new(uint)     // needs to be a pointer so the value persist across callback calls
+	*maxIndex = offset + limit
+	return func(key string, value interface{}) bool {
+		if !strings.HasSuffix(key, presuf) {
+			return false
+		}
+
+		element := value.(*list.Element)
+		record := element.Value.(*storeRecord)
+
+		if record.Expiry != 0 && record.ExpiresAt.Before(time.Now()) {
+			// record has expired -> add element to the expiredElements map
+			// and jump directly to the next element without increasing the index
+			expiredElements[record.Key] = element
+			return false
+		}
+
+		if *currentIndex >= offset && (*currentIndex < *maxIndex || *maxIndex == offset) {
+			*result = append(*result, record.Key)
+		}
+
+		*currentIndex++
+
+		if *currentIndex < *maxIndex || *maxIndex == offset {
+			return false
+		}
+		return true
+	}
+}

ocis-pkg/store/memory/multimemstore.go

@@ -0,0 +1,158 @@
+package memory
+
+import (
+	"sync"
+
+	"go-micro.dev/v4/store"
+)
+
+// In-memory store implementation using multiple MemStore to provide support
+// for multiple databases and tables.
+// Each table will be mapped to its own MemStore, which will be completely
+// isolated from the rest. In particular, each MemStore will have its own
+// capacity, so it's possible to have 10 MemStores with full capacity (512
+// by default)
+//
+// The options will be the same for all MemStores unless they're explicitly
+// initialized otherwise.
+//
+// Since each MemStore is isolated, the required synchronization caused by
+// concurrency will be minimal if the threads use different tables
+type MultiMemStore struct {
+	storeMap     map[string]*MemStore
+	storeMapLock sync.RWMutex
+	genOpts      []store.Option
+}
+
+// Create a new MultiMemStore. A new MemStore will be mapped based on the options.
+// A default MemStore will be mapped if no Database and Table aren't used.
+func NewMultiMemStore(opts ...store.Option) store.Store {
+	m := &MultiMemStore{
+		storeMap: make(map[string]*MemStore),
+		genOpts:  opts,
+	}
+	_ = m.Init(opts...)
+	return m
+}
+
+func (m *MultiMemStore) getMemStore(prefix string) *MemStore {
+	m.storeMapLock.RLock()
+	mStore, exists := m.storeMap[prefix]
+
+	if exists {
+		m.storeMapLock.RUnlock()
+		return mStore
+	}
+
+	m.storeMapLock.RUnlock()
+
+	// if not exists
+	newStore := NewMemStore(m.genOpts...).(*MemStore)
+
+	m.storeMapLock.Lock()
+	m.storeMap[prefix] = newStore
+	m.storeMapLock.Unlock()
+	return newStore
+}
+
+// Initialize the mapped MemStore based on the Database and Table values
+// from the options with the same options. The target MemStore will be
+// reinitialized if needed.
+func (m *MultiMemStore) Init(opts ...store.Option) error {
+	optList := store.Options{}
+	for _, opt := range opts {
+		opt(&optList)
+	}
+
+	prefix := optList.Database + "/" + optList.Table
+
+	mStore := m.getMemStore(prefix)
+	return mStore.Init(opts...)
+}
+
+// Get the options used to create the MultiMemStore.
+// Specific options for each MemStore aren't available
+func (m *MultiMemStore) Options() store.Options {
+	optList := store.Options{}
+	for _, opt := range m.genOpts {
+		opt(&optList)
+	}
+	return optList
+}
+
+// Write the record in the target MemStore based on the Database and Table
+// values from the options. A default MemStore will be used if no Database
+// and Table options are provided.
+// The write options will be forwarded to the target MemStore
+func (m *MultiMemStore) Write(r *store.Record, opts ...store.WriteOption) error {
+	wopts := store.WriteOptions{}
+	for _, opt := range opts {
+		opt(&wopts)
+	}
+
+	prefix := wopts.Database + "/" + wopts.Table
+
+	mStore := m.getMemStore(prefix)
+	return mStore.Write(r, opts...)
+}
+
+// Read the matching records in the target MemStore based on the Database and Table
+// values from the options. A default MemStore will be used if no Database
+// and Table options are provided.
+// The read options will be forwarded to the target MemStore.
+//
+// The expectations regarding the results (sort order, eviction policies, etc)
+// will be the same as the target MemStore
+func (m *MultiMemStore) Read(key string, opts ...store.ReadOption) ([]*store.Record, error) {
+	ropts := store.ReadOptions{}
+	for _, opt := range opts {
+		opt(&ropts)
+	}
+
+	prefix := ropts.Database + "/" + ropts.Table
+
+	mStore := m.getMemStore(prefix)
+	return mStore.Read(key, opts...)
+}
+
+// Delete the matching records in the target MemStore based on the Database and Table
+// values from the options. A default MemStore will be used if no Database
+// and Table options are provided.
+//
+// Matching records from other Tables won't be affected. In fact, we won't
+// access to other Tables
+func (m *MultiMemStore) Delete(key string, opts ...store.DeleteOption) error {
+	dopts := store.DeleteOptions{}
+	for _, opt := range opts {
+		opt(&dopts)
+	}
+
+	prefix := dopts.Database + "/" + dopts.Table
+
+	mStore := m.getMemStore(prefix)
+	return mStore.Delete(key, opts...)
+}
+
+// List the keys in the target MemStore based on the Database and Table
+// values from the options. A default MemStore will be used if no Database
+// and Table options are provided.
+// The list options will be forwarded to the target MemStore.
+func (m *MultiMemStore) List(opts ...store.ListOption) ([]string, error) {
+	lopts := store.ListOptions{}
+	for _, opt := range opts {
+		opt(&lopts)
+	}
+
+	prefix := lopts.Database + "/" + lopts.Table
+
+	mStore := m.getMemStore(prefix)
+	return mStore.List(opts...)
+}
+
+func (m *MultiMemStore) Close() error {
+	return nil
+}
+
+func (m *MultiMemStore) String() string {
+	return "MultiRadixMemStore"
+}

ocis-pkg/store/memory/multimemstore_test.go

@@ -0,0 +1,172 @@
+package memory
+
+import (
+	"context"
+	"strconv"
+	"testing"
+
+	"go-micro.dev/v4/store"
+)
+
+func TestWriteReadTables(t *testing.T) {
+	cache := NewMultiMemStore()
+
+	record1 := &store.Record{
+		Key:   "sameKey",
+		Value: []byte("from record1"),
+	}
+	record2 := &store.Record{
+		Key:   "sameKey",
+		Value: []byte("from record2"),
+	}
+
+	_ = cache.Write(record1)
+	_ = cache.Write(record2, store.WriteTo("DB02", "Table02"))
+
+	records1, _ := cache.Read("sameKey")
+	if len(records1) != 1 {
+		t.Fatalf("Wrong number of records, expected 1, got %d", len(records1))
+	}
+	if records1[0].Key != "sameKey" {
+		t.Errorf("Wrong key, expected \"sameKey\", got %s", records1[0].Key)
+	}
+	if string(records1[0].Value) != "from record1" {
+		t.Errorf("Wrong value, expected \"from record1\", got %s", string(records1[0].Value))
+	}
+
+	records2, _ := cache.Read("sameKey", store.ReadFrom("DB02", "Table02"))
+	if len(records2) != 1 {
+		t.Fatalf("Wrong number of records, expected 1, got %d", len(records2))
+	}
+	if records2[0].Key != "sameKey" {
+		t.Errorf("Wrong key, expected \"sameKey\", got %s", records2[0].Key)
+	}
+	if string(records2[0].Value) != "from record2" {
+		t.Errorf("Wrong value, expected \"from record2\", got %s", string(records2[0].Value))
+	}
+}
+
+func TestDeleteTables(t *testing.T) {
+	cache := NewMultiMemStore()
+
+	record1 := &store.Record{
+		Key:   "sameKey",
+		Value: []byte("from record1"),
+	}
+	record2 := &store.Record{
+		Key:   "sameKey",
+		Value: []byte("from record2"),
+	}
+
+	_ = cache.Write(record1)
+	_ = cache.Write(record2, store.WriteTo("DB02", "Table02"))
+
+	records1, _ := cache.Read("sameKey")
+	if len(records1) != 1 {
+		t.Fatalf("Wrong number of records, expected 1, got %d", len(records1))
+	}
+	if records1[0].Key != "sameKey" {
+		t.Errorf("Wrong key, expected \"sameKey\", got %s", records1[0].Key)
+	}
+	if string(records1[0].Value) != "from record1" {
+		t.Errorf("Wrong value, expected \"from record1\", got %s", string(records1[0].Value))
+	}
+
+	records2, _ := cache.Read("sameKey", store.ReadFrom("DB02", "Table02"))
+	if len(records2) != 1 {
+		t.Fatalf("Wrong number of records, expected 1, got %d", len(records2))
+	}
+	if records2[0].Key != "sameKey" {
+		t.Errorf("Wrong key, expected \"sameKey\", got %s", records2[0].Key)
+	}
+	if string(records2[0].Value) != "from record2" {
+		t.Errorf("Wrong value, expected \"from record2\", got %s", string(records2[0].Value))
+	}
+
+	_ = cache.Delete("sameKey")
+	if _, err := cache.Read("sameKey"); err != store.ErrNotFound {
+		t.Errorf("Key \"sameKey\" still exists after deletion")
+	}
+
+	records2, _ = cache.Read("sameKey", store.ReadFrom("DB02", "Table02"))
+	if len(records2) != 1 {
+		t.Fatalf("Wrong number of records, expected 1, got %d", len(records2))
+	}
+	if records2[0].Key != "sameKey" {
+		t.Errorf("Wrong key, expected \"sameKey\", got %s", records2[0].Key)
+	}
+	if string(records2[0].Value) != "from record2" {
+		t.Errorf("Wrong value, expected \"from record2\", got %s", string(records2[0].Value))
+	}
+}
+
+func TestListTables(t *testing.T) {
+	cache := NewMultiMemStore()
+
+	record1 := &store.Record{
+		Key:   "key001",
+		Value: []byte("from record1"),
+	}
+	record2 := &store.Record{
+		Key:   "key002",
+		Value: []byte("from record2"),
+	}
+
+	_ = cache.Write(record1)
+	_ = cache.Write(record2, store.WriteTo("DB02", "Table02"))
+
+	keys, _ := cache.List(store.ListFrom("DB02", "Table02"))
+	expectedKeys := []string{"key002"}
+	if len(keys) != 1 {
+		t.Fatalf("Wrong number of keys, expected 1, got %d", len(keys))
+	}
+	for index, key := range keys {
+		if expectedKeys[index] != key {
+			t.Errorf("Wrong key for index %d, expected %s, got %s", index, expectedKeys[index], key)
+		}
+	}
+}
+
+func TestWriteSizeLimit(t *testing.T) {
+	cache := NewMultiMemStore(
+		store.WithContext(
+			NewContext(
+				context.Background(),
+				map[string]interface{}{
+					"maxCap": 2,
+				},
+			),
+		),
+	)
+
+	record := &store.Record{}
+	for i := 0; i < 4; i++ {
+		v := strconv.Itoa(i)
+		record.Key = v
+		record.Value = []byte(v)
+		_ = cache.Write(record)
+		_ = cache.Write(record, store.WriteTo("DB02", "Table02"))
+	}
+
+	keys1, _ := cache.List()
+	expectedKeys1 := []string{"2", "3"}
+	if len(keys1) != 2 {
+		t.Fatalf("Wrong number of keys, expected 2, got %d", len(keys1))
+	}
+	for index, key := range keys1 {
+		if expectedKeys1[index] != key {
+			t.Errorf("Wrong key for index %d, expected %s, got %s", index, expectedKeys1[index], key)
+		}
+	}
+
+	keys2, _ := cache.List(store.ListFrom("DB02", "Table02"))
+	expectedKeys2 := []string{"2", "3"}
+	if len(keys2) != 2 {
+		t.Fatalf("Wrong number of keys, expected 2, got %d", len(keys2))
+	}
+	for index, key := range keys2 {
+		if expectedKeys2[index] != key {
+			t.Errorf("Wrong key for index %d, expected %s, got %s", index, expectedKeys2[index], key)
+		}
+	}
+}

ocis-pkg/store/memory/utils.go

@@ -0,0 +1,63 @@
+package memory
+
+import (
+	"time"
+
+	"go-micro.dev/v4/store"
+)
+
+func toStoreRecord(src *store.Record, options store.WriteOptions) *storeRecord {
+	newRecord := &storeRecord{}
+	newRecord.Key = src.Key
+	newRecord.Value = make([]byte, len(src.Value))
+	copy(newRecord.Value, src.Value)
+
+	// set base ttl duration and expiration time based on the record
+	newRecord.Expiry = src.Expiry
+	if src.Expiry != 0 {
+		newRecord.ExpiresAt = time.Now().Add(src.Expiry)
+	}
+
+	// overwrite ttl duration and expiration time based on options
+	if !options.Expiry.IsZero() {
+		// options.Expiry is a time.Time, newRecord.Expiry is a time.Duration
+		newRecord.Expiry = time.Until(options.Expiry)
+		newRecord.ExpiresAt = options.Expiry
+	}
+
+	// TTL option takes precedence over expiration time
+	if options.TTL != 0 {
+		newRecord.Expiry = options.TTL
+		newRecord.ExpiresAt = time.Now().Add(options.TTL)
+	}
+
+	newRecord.Metadata = make(map[string]interface{})
+	for k, v := range src.Metadata {
+		newRecord.Metadata[k] = v
+	}
+	return newRecord
+}
+
+func fromStoreRecord(src *storeRecord) *store.Record {
+	newRecord := &store.Record{}
+	newRecord.Key = src.Key
+	newRecord.Value = make([]byte, len(src.Value))
+	copy(newRecord.Value, src.Value)
+	if src.Expiry != 0 {
+		newRecord.Expiry = time.Until(src.ExpiresAt)
+	}
+
+	newRecord.Metadata = make(map[string]interface{})
+	for k, v := range src.Metadata {
+		newRecord.Metadata[k] = v
+	}
+	return newRecord
+}
+
+func reverseString(s string) string {
+	r := []rune(s)
+	for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 {
+		r[i], r[j] = r[j], r[i]
+	}
+	return string(r)
+}