Write documents of the program.

Add README.md on the design of the whole program, and how its every
part(listener, filter) works, finally how to compile and use them.

Besides, notes.md records the things and technology learned in this
program, such as how to read kernel src, how the pthread_create/fork/
clone syscall works on processes and threads, the techs used to make
docker container works well, and books to be read. Good good study,
day day up.

1 files changed, 12 insertions, 3 deletions

diff --git a/listener/mongo.go b/listener/mongo.go
index a51350e..36c471c 100644
--- a/listener/mongo.go
+++ b/listener/mongo.go
@@ -31,18 +31,27 @@ func (mc *mongoClient) init(dbName, colName string) error {
 
 func (mc *mongoClient) Connect(dbName, colName string) error {
         var err error
-        mc.client, err = mongo.NewClient(options.Client().ApplyURI("mongodb://localhost:27017"))
+        // 设置连接MongoDB的参数
+        clientOptions := options.Client().ApplyURI("mongodb://" + *mongoURI)
 
+        // 创建一个带有超时的上下文
+        ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+        defer cancel() // 确保在函数退出时取消上下文
+
+        // 使用带超时的上下文连接到MongoDB
+        mc.client, err = mongo.Connect(ctx, clientOptions)
         if err != nil {
                 return err
         }
 
-        ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
-        err = mc.client.Connect(ctx)
+        // 尝试ping数据库以检查连接是否成功
+        err = mc.client.Ping(ctx, nil)
         if err != nil {
                 return err
         }
 
+        fmt.Println("Connected to MongoDB!")
+
         mc.col = mc.client.Database(dbName).Collection(colName)
         mc.dbName = dbName
         mc.colName = colName