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Qmgo is a Go driver for MongoDB . It is based on MongoDB official driver, but easier to use like mgo (such as the chain call).

• Qmgo allows users to use the new features of MongoDB in a more elegant way.

• Qmgo is the first choice for migrating from mgo to the new MongoDB driver with minimal code changes.

-Go 1.10 and above.

-MongoDB 2.6 and above.

• CRUD to documents, with all official supported options
• Sort、limit、count、select、distinct
• Transactions
• Hooks
• Automatically default and custom fields
• Predefine operator keys
• Aggregate、indexes operation、cursor
• Validation tags
• Plugin

• Use go mod to automatically install dependencies by import github.com/qiniu/qmgo

Or

• Use go get github.com/qiniu/qmgo

• Start

  import and create a new connection

  import (
      "context"
    
      "github.com/qiniu/qmgo"
  )
  
  ctx := context.Background()
  client, err := qmgo.NewClient(ctx, &qmgo.Config{Uri: "mongodb://localhost:27017"})
  db := client.Database("class")
  coll := db.Collection("user")

  If your connection points to a fixed database and collection, recommend using the following way to initialize the connection. All operations can be based on cli:

  cli, err := qmgo.Open(ctx, &qmgo.Config{Uri: "mongodb://localhost:27017", Database: "class", Coll: "user"})

  The following examples will be based on cli, if you use the first way for initialization, replace cli with client、db or coll

  Make sure to defer a call to Disconnect after instantiating your client:

  defer func() {
  if err = cli.Close(ctx); err != nil {
          panic(err)
      }
  }()

• Create index

  Before doing the operation, we first initialize some data:

  type UserInfo struct {
      Name   string `bson:"name"`
      Age    uint16 `bson:"age"`
      Weight uint32 `bson:"weight"`
  }
  
  var userInfo = UserInfo{
      Name: "xm",
      Age: 7,
      Weight: 40,
  }

  Create index

  cli.CreateOneIndex(context.Background(), options.IndexModel{Key: []string{"name"}})
  cli.CreateIndexes(context.Background(), []options.IndexModel{{Key: []string{"id2", "id3"}}})

• Insert a document

  // insert one document
  result, err := cli.InsertOne(ctx, userInfo)

• Find a document

  // find one document
    one := UserInfo{}
    err = cli.Find(ctx, bson.M{"name": userInfo.Name}).One(&one)

• Delete documents

  err = cli.Remove(ctx, bson.M{"age": 7})

• Insert multiple data

  // multiple insert
  var userInfos = []UserInfo{
      UserInfo{Name: "a1", Age: 6, Weight: 20},
      UserInfo{Name: "b2", Age: 6, Weight: 25},
      UserInfo{Name: "c3", Age: 6, Weight: 30},
      UserInfo{Name: "d4", Age: 6, Weight: 35},
      UserInfo{Name: "a1", Age: 7, Weight: 40},
      UserInfo{Name: "a1", Age: 8, Weight: 45},
  }
  result, err = cli.Collection.InsertMany(ctx, userInfos)

• Search all, sort and limit

  // find all, sort and limit
  batch := []UserInfo{}
  cli.Find(ctx, bson.M{"age": 6}).Sort("weight").Limit(7).All(&batch)

• Count

  count, err := cli.Find(ctx, bson.M{"age": 6}).Count()

• Update

  // UpdateOne one
  err := cli.UpdateOne(ctx, bson.M{"name": "d4"}, bson.M{"$set": bson.M{"age": 7}})
  
  // UpdateAll
  result, err := cli.UpdateAll(ctx, bson.M{"age": 6}, bson.M{"$set": bson.M{"age": 10}})

• Select

  err := cli.Find(ctx, bson.M{"age": 10}).Select(bson.M{"age": 1}).One(&one)

• Aggregate

  matchStage := bson.D{{"$match", []bson.E{{"weight", bson.D{{"$gt", 30}}}}}}
  groupStage := bson.D{{"$group", bson.D{{"_id", "$name"}, {"total", bson.D{{"$sum", "$age"}}}}}}
  var showsWithInfo []bson.M
  err = cli.Aggregate(context.Background(), Pipeline{matchStage, groupStage}).All(&showsWithInfo)

• Support All mongoDB Options when create connection

  poolMonitor := &event.PoolMonitor{
      Event: func(evt *event.PoolEvent) {
          switch evt.Type {
          case event.GetSucceeded:
              fmt.Println("GetSucceeded")
          case event.ConnectionReturned:
              fmt.Println("ConnectionReturned")
          }
      },
  }
  opt := options.Client().SetPoolMonitor(poolMonitor)  // more options use the chain options.
  cli, err := Open(ctx, &Config{Uri: URI, Database: DATABASE, Coll: COLL}, opt) 
  

• Transactions

  The super simple and powerful transaction, with features like timeout、retry:

  callback := func(sessCtx context.Context) (interface{}, error) {
      // Important: make sure the sessCtx used in every operation in the whole transaction
      if _, err := cli.InsertOne(sessCtx, bson.D{{"abc", int32(1)}}); err != nil {
          return nil, err
      }
      if _, err := cli.InsertOne(sessCtx, bson.D{{"xyz", int32(999)}}); err != nil {
          return nil, err
      }
      return nil, nil
  }
  result, err = cli.DoTransaction(ctx, callback)

  More about transaction

• Predefine operator keys

  // aggregate
  matchStage := bson.D{{operator.Match, []bson.E{{"weight", bson.D{{operator.Gt, 30}}}}}}
  groupStage := bson.D{{operator.Group, bson.D{{"_id", "$name"}, {"total", bson.D{{operator.Sum, "$age"}}}}}}
  var showsWithInfo []bson.M
  err = cli.Aggregate(context.Background(), Pipeline{matchStage, groupStage}).All(&showsWithInfo)

• Hooks

  Qmgo flexible hooks:

  type User struct {
      Name         string    `bson:"name"`
      Age          int       `bson:"age"`
  }
  func (u *User) BeforeInsert(ctx context.Context) error {
      fmt.Println("before insert called")
      return nil
  }
  func (u *User) AfterInsert(ctx context.Context) error {
      fmt.Println("after insert called")
      return nil
  }
  
  u := &User{Name: "Alice", Age: 7}
  _, err := cli.InsertOne(context.Background(), u)

  More about hooks

• Automatically fields

  Qmgo support two ways to make specific fields automatically update in specific API

  • Default fields

  Inject field.DefaultField in document struct, Qmgo will update createAt、updateAt and _id in update and insert operation.

  type User struct {
    field.DefaultField `bson:",inline"`
  
    Name string `bson:"name"`
    Age  int    `bson:"age"`
  }
  
  u := &User{Name: "Lucas", Age: 7}
  _, err := cli.InsertOne(context.Background(), u)
  // Fields with tag createAt、updateAt and _id will be generated automatically 

  • Custom fields

  Define the custom fields, Qmgo will update them in update and insert operation.

  type User struct {
      Name string `bson:"name"`
      Age  int    `bson:"age"`
  
      MyId         string    `bson:"myId"`
      CreateTimeAt time.Time `bson:"createTimeAt"`
      UpdateTimeAt int64     `bson:"updateTimeAt"`
  }
  // Define the custom fields
  func (u *User) CustomFields() field.CustomFieldsBuilder {
      return field.NewCustom().SetCreateAt("CreateTimeAt").SetUpdateAt("UpdateTimeAt").SetId("MyId")
  }
  
  u := &User{Name: "Lucas", Age: 7}
  _, err := cli.InsertOne(context.Background(), u)
  // CreateTimeAt、UpdateTimeAt and MyId will be generated automatically 
  
  // suppose Id and ui is ready
  err = cli.ReplaceOne(context.Background(), bson.M{"_id": Id}, &ui)
  // UpdateTimeAt will update

  Check examples here

  More about automatically fields

• Validation tags

  Qmgo Validation tags is Based on go-playground/validator.

  So Qmgo support all validations on structs in go-playground/validator, such as:

  type User struct {
      FirstName string            `bson:"fname"`
      LastName  string            `bson:"lname"`
      Age       uint8             `bson:"age" validate:"gte=0,lte=130" `    // Age must in [0,130]
      Email     string            `bson:"e-mail" validate:"required,email"` //  Email can't be empty string, and must has email format
      CreateAt  time.Time         `bson:"createAt" validate:"lte"`          // CreateAt must lte than current time
      Relations map[string]string `bson:"relations" validate:"max=2"`       // Relations can't has more than 2 elements
  }

  Qmgo tags only supported in following API： InsertOne、InsertyMany、Upsert、UpsertId、ReplaceOne

• Plugin

  • Implement following method:

  func Do(ctx context.Context, doc interface{}, opType operator.OpType, opts ...interface{}) error{
    // do anything
  }

  • Call Register() in package middleware, register the method Do

    Qmgo will call Do before and after the operation

  middleware.Register(Do)

  Example

  The hook、automatically fields and validation tags in Qmgo run on plugin.

Below we give an example of multi-file search、sort and limit to illustrate the similarities between qmgo and mgo and the improvement compare to go.mongodb.org/mongo-driver. How do we do ingo.mongodb.org/mongo-driver:

// go.mongodb.org/mongo-driver
// find all, sort and limit
findOptions := options.Find()
findOptions.SetLimit(7) // set limit
var sorts D
sorts = append(sorts, E{Key: "weight", Value: 1})
findOptions.SetSort(sorts) // set sort

batch := []UserInfo{}
cur, err := coll.Find(ctx, bson.M{"age": 6}, findOptions)
cur.All(ctx, &batch)

How do we do in Qmgo and mgo:

// qmgo
// find all, sort and limit
batch := []UserInfo{}
cli.Find(ctx, bson.M{"age": 6}).Sort("weight").Limit(7).All(&batch)

// mgo
// find all, sort and limit
coll.Find(bson.M{"age": 6}).Sort("weight").Limit(7).All(&batch)

Differences between qmgo and mgo

The Qmgo project welcomes all contributors. We appreciate your help!

• Join qmgo discussions