fix: add locking in connection cache

connection.go

@@ -18,7 +18,7 @@ type ConnectionConfig struct {
 }
 
 // SetDefaultClient sets the default MongoDB client to be used by the package.
-func SetDefaultClient(client *mongo.Client, dbName string) {
+func SetDefaultClient(client *mongo.Client) {
 	mClient = client
 }
 

connection_cache.go

@@ -1,21 +1,54 @@
 package mgod
 
-import "go.mongodb.org/mongo-driver/mongo"
+import (
+	"sync"
+
+	"go.mongodb.org/mongo-driver/mongo"
+)
 
 // dbConnCache is a cache of MongoDB database connections.
-var dbConnCache map[string]*mongo.Database
+var dbConnCache *connectionCache
 
 func init() {
-	dbConnCache = make(map[string]*mongo.Database)
+	dbConnCache = newConnectionCache()
+}
+
+// connectionCache is a thread safe construct to cache MongoDB database connections.
+type connectionCache struct {
+	cache map[string]*mongo.Database
+	mux   sync.RWMutex
+}
+
+func newConnectionCache() *connectionCache {
+	return &connectionCache{
+		cache: map[string]*mongo.Database{},
+	}
+}
+
+func (c *connectionCache) Get(dbName string) *mongo.Database {
+	c.mux.RLock()
+	defer c.mux.RUnlock()
+
+	return c.cache[dbName]
+}
+
+func (c *connectionCache) Set(dbName string, db *mongo.Database) {
+	c.mux.Lock()
+	defer c.mux.Unlock()
+
+	c.cache[dbName] = db
 }
 
 // getDBConn returns a MongoDB database connection from the cache.
 // If the connection is not present in the cache, it creates a new connection and adds it to the cache (Write-through policy).
 func getDBConn(dbName string) *mongo.Database {
+	dbConn := dbConnCache.Get(dbName)
+
 	// Initialize the cache entry if it is not present.
-	if dbConnCache[dbName] == nil {
-		dbConnCache[dbName] = mClient.Database(dbName)
+	if dbConn == nil {
+		dbConn = mClient.Database(dbName)
+		dbConnCache.Set(dbName, dbConn)
 	}
 
-	return dbConnCache[dbName]
+	return dbConn
 }

docs/basic_usage.md

@@ -10,7 +10,7 @@ import "github.com/Lyearn/mgod"
 
 func init() {
 	// client is the MongoDB client obtained using Go Mongo Driver's Connect method.
-	mgod.SetDefaultClient(client, dbName)
+	mgod.SetDefaultClient(client)
 }
 ```
 

docs/multi_tenancy.md

@@ -37,8 +37,6 @@ The `EntityMongoModel` is always bound to the specified database at the time of
 :::
 
 ```go
-amount := 10000
-
 result, _ := tenant1Model.FindOne(context.TODO(), bson.M{"name": "Gopher Tenant 2"})
 // result will be <nil> value in this case
 ```

entity_mongo_model_test.go

@@ -86,8 +86,11 @@ func (s *EntityMongoModelSuite) setupData() {
 }
 
 func (s *EntityMongoModelSuite) getModel() mgod.EntityMongoModel[testEntity] {
+	dbName := "mgoddb"
+	collection := "entityMongoModel"
 	schemaOpts := schemaopt.SchemaOptions{Timestamps: true}
-	opts := mgod.NewEntityMongoModelOptions("mgoddb", "entityMongoModel", &schemaOpts)
+
+	opts := mgod.NewEntityMongoModelOptions(dbName, collection, &schemaOpts)
 	model, err := mgod.NewEntityMongoModel(testEntity{}, *opts)
 	if err != nil {
 		s.T().Fatal(err)