一文帶你深入探索Golang操作mongodb的方法

2023-02-09 06:01:37

package main

import (
	"context"
	"fmt"
	"log"

	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"go.mongodb.org/mongo-driver/bson"
)

type Student struct {
	Name string
	Age int
}

func main() {
	// 設定使用者端連線設定
	clientOptions := options.Client().ApplyURI("mongodb://admin:123456@localhost:27017")

	// 連線到MongoDB
	client, err := mongo.Connect(context.TODO(), clientOptions)
	if err != nil {
		log.Fatal(err)
	}

	// 檢查連線
	err = client.Ping(context.TODO(), nil)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("Connected to MongoDB!")


	collection := client.Database("q1mi").Collection("student")
    

        s1 := Student{"小紅", 12}
	s2 := Student{"小蘭", 10}
	s3 := Student{"小黃", 11}

	insertResult, err := collection.InsertOne(context.TODO(), s1)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("Inserted a single document: ", insertResult.InsertedID)

	students := []interface{}{s2, s3}
	insertManyResult, err := collection.InsertMany(context.TODO(), students)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("Inserted multiple documents: ", insertManyResult.InsertedIDs)



	filter := bson.D{{"name", "小蘭"}}

	// 建立一個Student變數用來接收查詢的結果
	var result Student
	err = collection.FindOne(context.TODO(), filter).Decode(&result)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("Found a single document: %+vn", result)
}

1.建立GO專案工程

go之前對第三方包的管理不上心，其他語言比如python有pip，nodejs有npm，而go卻沒有一個官方的管理工具。

在go 1.11之前，開發者需要要關注GOPATH環境變數，這對於開發者來說不友好。

經過幾次變更後，go於1.12版本開始正式使用go Module，go終於有了一個官方的處理方式，開發者也可以拋棄GOPATH了。

go的包管理包括：

建立一個目錄做工程目錄
初始化工程目錄
設定包下載代理
安裝依賴包

1.1初始化開發工程

➜ go mkdir mongo
➜ go cd mongo

使用mod命令初始化

go mod init 檔名

➜ go mod init mongo
go: creating new go.mod: module mongo
➜ ls -al
total 8
drwxr-xr-x 3 ljk staff 96 2 2 22:02 .
drwxr-xr-x 5 ljk staff 160 2 2 22:02 ..
-rw-r--r-- 1 ljk staff 22 2 2 22:02 go.mod

初始化成功之後當前目錄下會新建一個go.mod檔案，用於記錄安裝的模組和包

➜ mongo cat go.mod
module mongo

go 1.18

設定包下載代理

go env -w GO111MODULE=on
go env -w GOPROXY=https://goproxy.io,direct

1.2安裝mongo

下載 mongodb 映象

➜  mod docker pull mongo:latest
latest: Pulling from library/mongo
70cf24b16239: Pull complete
197e79a59399: Pull complete
1a54d1916136: Pull complete
8547f0e899b2: Pull complete
315a8963db2b: Pull complete
0fce25e2f34f: Pull complete
1ce995f0f803: Pull complete
e3bfd9b7202d: Pull complete
07bd59396de7: Pull complete
Digest: sha256:3fe527dcddf277d4d5b278f5f03ddea5173cee84c792d12c5ac90c36ba40ba7a
Status: Downloaded newer image for mongo:latest
docker.io/library/mongo:latest

➜  mod docker images
REPOSITORY   TAG       IMAGE ID       CREATED        SIZE
mongo        latest    b2fa76e584f6   20 hours ago   618MB
redis        5.0.4     b61ab367aee1   3 years ago    90MB

執行 mongodb 容器

➜  mod docker run -itd --name mongo -p 27017:27017 mongo --auth
f3116f4e2ed1d81e7707ee42b67c01fdcd648461e1e7cd35ad0815dae2c1af5f
➜  mod
➜  mod
➜  mod docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED         STATUS         PORTS                      NAMES
f3116f4e2ed1   mongo     "docker-entrypoint.s…"   7 seconds ago   Up 6 seconds   0.0.0.0:27017->27017/tcp   mongo

登入 mongodb 容器並設定庫許可權

➜  mod docker exec -it mongo mongosh admin
Current Mongosh Log ID:	63dbcaa4fb21cc3d13dcfde2
Connecting to:		mongodb://127.0.0.1:27017/admin?directConnection=true&serverSelectionTimeoutMS=2000&appName=mongosh+1.6.2
Using MongoDB:		6.0.4
Using Mongosh:		1.6.2

For mongosh info see: https://docs.mongodb.com/mongodb-shell/


To help improve our products, anonymous usage data is collected and sent to MongoDB periodically (https://www.mongodb.com/legal/privacy-policy).
You can opt-out by running the disableTelemetry() command.

admin> db.createUser({ user:'admin',pwd:'123456',roles:[ { role:'userAdminAnyDatabase', db: 'admin'},"readWriteAnyDatabase"]});
{ ok: 1 }
admin> db.auth('admin', '123456')
{ ok: 1 }
admin>

1.3偵錯執行

go run 可以直接下載依賴的模組，然後執行模組。

➜  mongo go run mongo_dev.go
go: downloading go.mongodb.org/mongo-driver v1.11.1
go: downloading github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d
go: downloading github.com/pkg/errors v0.9.1
go: downloading github.com/golang/snappy v0.0.1
go: downloading github.com/klauspost/compress v1.13.6
go: downloading github.com/montanaflynn/stats v0.0.0-20171201202039-1bf9dbcd8cbe
go: downloading github.com/xdg-go/scram v1.1.1
go: downloading github.com/xdg-go/stringprep v1.0.3
go: downloading golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d
go: downloading golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
go: downloading golang.org/x/text v0.3.7
go: downloading github.com/xdg-go/pbkdf2 v1.0.0
Connected to MongoDB!
Inserted a single document:  ObjectID("63dbcaf83e1180444cc7dca1")
Inserted multiple documents:  [ObjectID("63dbcaf83e1180444cc7dca2") ObjectID("63dbcaf83e1180444cc7dca3")]
Found a single document: {Name:小蘭 Age:10}

1.4編譯執行

如果想通過編譯的方法執行程式而不是偵錯方法，可以通過一下三步：

go mod tidy 自動更新需要的依賴檔案
go mod download 根據go.mod下載模組
go build mongo_dev.go 編譯go
執行go程式

➜  mongo_three go mod tidy
go: finding module for package go.mongodb.org/mongo-driver/mongo/options
go: finding module for package go.mongodb.org/mongo-driver/bson
go: finding module for package go.mongodb.org/mongo-driver/mongo
go: found go.mongodb.org/mongo-driver/bson in go.mongodb.org/mongo-driver v1.11.1
go: found go.mongodb.org/mongo-driver/mongo in go.mongodb.org/mongo-driver v1.11.1
go: found go.mongodb.org/mongo-driver/mongo/options in go.mongodb.org/mongo-driver v1.11.1
go: downloading github.com/google/go-cmp v0.5.2
go: downloading github.com/stretchr/testify v1.6.1
go: downloading github.com/tidwall/pretty v1.0.0
go: downloading github.com/kr/pretty v0.1.0
go: downloading github.com/kr/text v0.1.0
go: downloading github.com/davecgh/go-spew v1.1.1
go: downloading github.com/pmezard/go-difflib v1.0.0
go: downloading gopkg.in/yaml.v3 v3.0.1
go: downloading golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543

更新依賴檔案之後，go.mod 檔案中就記載了下載的模組資訊，包括路徑和版本資訊

➜  mongo cat go.mod
module mongo

go 1.18

require (
	github.com/golang/snappy v0.0.1 // indirect
	github.com/klauspost/compress v1.13.6 // indirect
	github.com/montanaflynn/stats v0.0.0-20171201202039-1bf9dbcd8cbe // indirect
	github.com/pkg/errors v0.9.1 // indirect
	github.com/xdg-go/pbkdf2 v1.0.0 // indirect
	github.com/xdg-go/scram v1.1.1 // indirect
	github.com/xdg-go/stringprep v1.0.3 // indirect
	github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d // indirect
	go.mongodb.org/mongo-driver v1.11.1 // indirect
	golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d // indirect
	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
	golang.org/x/text v0.3.7 // indirect
)

下載依賴的模組

➜  mongo go mod download

模組真正的檔案放在gopath路徑下的pkg路徑下

~ go env 
.
.
GOPATH="/Users/ljk/Documents/go"

➜  mod pwd
/Users/ljk/Documents/go/pkg/mod
➜  mod ls
cache          github.com     go.mongodb.org golang.org

編譯程式

➜  mongo go build mongo_dev.go
➜  mongo ls
go.mod       go.sum       mongo_dev    mongo_dev.go

執行可執行檔案。

➜  mongo ./mongo_dev
Connected to MongoDB!
Inserted a single document:  ObjectID("63e1096ce7684b84e5b3229a")
Inserted multiple documents:  [ObjectID("63e1096ce7684b84e5b3229b") ObjectID("63e1096ce7684b84e5b3229c")]
Found a single document: {Name:小蘭 Age:10}

可以看到程式連線到mongodb，並且寫入了三條資料，查詢了一次。