Golang学习系列第六天：操作MongoDB

0.  ssh连接linux（我用的centos7），略
1.  安装MongoDB 
可以直接到MongoDB官网https://docs.mongodb.com/manual/tutorial/install-mongodb-on-red-hat-tarball/根据样板安装：，可根据自己的电脑操作系统下载对应的版本，我下载的是mongodb-linux-x86_64-4.0.0.tgz安装包，不过也可以直接点击下面这个链接直接下载 https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-4.0.0.tgz，即

wget https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-4.0.0.tgz

下载完毕后解压缩

[root@master dgm]# tar -zxf mongodb-linux-x86_64-4.0.0.tgz

名字那么长，可以进行重命名：

[root@master dgm]# mv mongodb-linux-x86_64-4.0.0 mongodb

进入到mongodb主目录下：

cd mongodb

分别建配置文件、数据目录、日志文件

建立配置文件

vim mongodb.conf

键入以下内容

#端口号
port=27017
#db目录
dbpath=/dgm/mongodb/data/db
#日志目录
logpath=/dgm/mongodb/logs/mongodb.log
#后台
fork=true
#日志输出
logappend=true
#允许远程IP连接
bind_ip=0.0.0.0

注意路径根据自己电脑的实际情况填写

建立数据目录和日志文件

[root@master mongodb]# mkdir -p data/db logs
[root@master mongodb]# touch logs/mongodb.log

编辑环境配置 

vim /etc/profile

追加以下内容：

​

切记路径按实际情况写

source /etc/profile

启动mongodb测试

[root@master mongodb]# mongod --config mongodb.conf 

​

最后连接测试

[root@master mongodb]# mongo

​

为了安全起见，我们需要设置相应的用户名和密码。

创建数据库系统管理员

> use admin
switched to db admin
> db.createUser({ user: "admin", pwd: "12345678", roles: [{ role: "userAdminAnyDatabase", db: "admin" }] })
Successfully added user: {
	"user" : "admin",
	"roles" : [
		{
			"role" : "userAdminAnyDatabase",
			"db" : "admin"
		}
	]
}
> db.auth("admin", "12345678")
1

 修改mongodb配置追加认证标志

## 是否以安全认证方式运行，默认是不认证的非安全方式
#noauth = true
auth = true

然后重启mongodb服务

 再次通过shell进入mongodb，创建需要管理的mongodb 数据的账号密码，此处是库是douyin，用户名是root，密码87654321

[root@master mongorest]# mongo
> use admin
switched to db admin
> db.auth("admin", "12345678")
1
> use douyin
switched to db douyin
> db.createUser({ user: "root", pwd: "87654321", roles: [{ role: "dbOwner", db: "douyin" }] })
Successfully added user: {
	"user" : "root",
	"roles" : [
		{
			"role" : "dbOwner",
			"db" : "douyin"
		}
	]
}
> use admin
switched to db admin
> db.system.users.find()
{ "_id" : "admin.admin", "user" : "admin", "db" : "admin", "credentials" : { "SCRAM-SHA-1" : { "iterationCount" : 10000, "salt" : "Qp+6YETcIsDyrPPwQVtWHQ==", "storedKey" : "0X27QePHJknrd+5qg4Ai5TeEWjg=", "serverKey" : "ZYRXkrQfJY875GC1qf76xAmBFow=" }, "SCRAM-SHA-256" : { "iterationCount" : 15000, "salt" : "E3LYqVegf93pTNjwNqXh4Gy8zQ1qNXXz0HtHHw==", "storedKey" : "yUZq7I9/w8Kf6fLu6Q8OqJcKNv77KUDmvGo4gEGi5ng=", "serverKey" : "+sNL0T/gfa+B+HoNSeid+HCC7OulvZlvSi2FDtE3wfk=" } }, "roles" : [ { "role" : "userAdminAnyDatabase", "db" : "admin" } ] }
{ "_id" : "douyin.root", "user" : "root", "db" : "douyin", "credentials" : { "SCRAM-SHA-1" : { "iterationCount" : 10000, "salt" : "gVHTUMMMC38slLBW15kxPw==", "storedKey" : "591b17pCtkEZcVXf7ZO/Ll4DPAs=", "serverKey" : "vd5w+StBi9eXfViwWY30tc66lmo=" }, "SCRAM-SHA-256" : { "iterationCount" : 15000, "salt" : "2CHwq56N9MLts2v+PSqN3qs6tpWX1BKHY0aTDA==", "storedKey" : "2v5I/nnNoGVst2tTljoQs34z7bDNZS4euv6nAFZGxyc=", "serverKey" : "/F2xcR86DH4ErEEEbDyprmm1ttnl1o6sniWrj3vjjTY=" } }, "roles" : [ { "role" : "dbOwner", "db" : "douyin" } ] }
> exit

 测试密码权限是否生效

先看失败的尝试案例

[root@master mongorest]# mongo
MongoDB shell version v4.0.0
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 4.0.0
> use douyin
switched to db douyin
> show collections
Warning: unable to run listCollections, attempting to approximate collection names by parsing connectionStatus
> db.douyin.find()
Error: error: {
	"ok" : 0,
	"errmsg" : "command find requires authentication",
	"code" : 13,
	"codeName" : "Unauthorized"
}
> 

再看成功的案例

[root@master mongorest]# mongo "mongodb://root:87654321@127.0.0.1:27017/douyin"
MongoDB shell version v4.0.0
connecting to: mongodb://127.0.0.1:27017/douyin
MongoDB server version: 4.0.0
> show collections
douyin
> db.douyin.find()
{ "_id" : ObjectId("5f083625b8b307c7e889f276") }
{ "_id" : ObjectId("5f08365cb8b307c7e889f277"), "name" : "dongguangming", "age" : 31 }
> 

很好，权限认证通过了，可以查询数据记录 

2.  golang操作MongoDB

2.1  增加书籍接口

新建go文件mongdb-add.go，键入以下代码

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	"goji.io"
	"goji.io/pat"
	"gopkg.in/mgo.v2"
)

func ErrorWithJSON(w http.ResponseWriter, message string, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	fmt.Fprintf(w, "{message: %q}", message)
}

func ResponseWithJSON(w http.ResponseWriter, json []byte, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	w.Write(json)
}

type Book struct {
	ISBN    string   `json:"isbn"`
	Title   string   `json:"title"`
	Authors []string `json:"authors"`
	Price   string   `json:"price"`
}

func main() {
	session, err := mgo.Dial("mongodb://root:87654321@127.0.0.1:27017/douyin")
	if err != nil {
		panic(err)
	}
	defer session.Close()

	session.SetMode(mgo.Monotonic, true)
	ensureIndex(session)

	mux := goji.NewMux()
	mux.HandleFunc(pat.Post("/books"), addBook(session))
	http.ListenAndServe("192.168.8.200:8888", mux)
}

func ensureIndex(s *mgo.Session) {
	session := s.Copy()
	defer session.Close()

	c := session.DB("douyin").C("books")

	index := mgo.Index{
		Key:        []string{"isbn"},
		Unique:     true,
		DropDups:   true,
		Background: true,
		Sparse:     true,
	}
	err := c.EnsureIndex(index)
	if err != nil {
		panic(err)
	}
}


func addBook(s *mgo.Session) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		session := s.Copy()
		defer session.Close()

		var book Book
		decoder := json.NewDecoder(r.Body)
		err := decoder.Decode(&book)
		if err != nil {
			ErrorWithJSON(w, "数据格式不对", http.StatusBadRequest)
			return
		}

		c := session.DB("douyin").C("books")

		err = c.Insert(book)
		if err != nil {
			if mgo.IsDup(err) {
				ErrorWithJSON(w, "书的isbn已存在", http.StatusBadRequest)
				return
			}

			ErrorWithJSON(w, "服务器错误", http.StatusInternalServerError)
			log.Println("添加书失败！！！: ", err)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		w.Header().Set("Location", r.URL.Path+"/"+book.ISBN)
		w.WriteHeader(http.StatusCreated)
	}
}

然后就就执行以上程序，

go run  mongdb-add.go

打开postman测试

​

查询数据库是否已存在

​

2.2  查询单书籍接口

新建go文件mongdb-select.go，键入以下代码

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	"goji.io"
	"goji.io/pat"
	"gopkg.in/mgo.v2"
    "gopkg.in/mgo.v2/bson"
)

func ErrorWithJSON(w http.ResponseWriter, message string, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	fmt.Fprintf(w, "{message: %q}", message)
}

func ResponseWithJSON(w http.ResponseWriter, json []byte, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	w.Write(json)
}

type Book struct {
	ISBN    string   `json:"isbn"`
	Title   string   `json:"title"`
	Authors []string `json:"authors"`
	Price   string   `json:"price"`
}

func main() {
	session, err := mgo.Dial("mongodb://root:87654321@127.0.0.1:27017/douyin")
	if err != nil {
		panic(err)
	}
	defer session.Close()

	session.SetMode(mgo.Monotonic, true)
	ensureIndex(session)

	mux := goji.NewMux()
    mux.HandleFunc(pat.Get("/books/:isbn"), bookByISBN(session))	 
    http.ListenAndServe("192.168.8.200:8888", mux)
}

func ensureIndex(s *mgo.Session) {
	session := s.Copy()
	defer session.Close()

	c := session.DB("douyin").C("books")

	index := mgo.Index{
		Key:        []string{"isbn"},
		Unique:     true,
		DropDups:   true,
		Background: true,
		Sparse:     true,
	}
	err := c.EnsureIndex(index)
	if err != nil {
		panic(err)
	}
}


func bookByISBN(s *mgo.Session) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		session := s.Copy()
		defer session.Close()

		isbn := pat.Param(r, "isbn")

		c := session.DB("store").C("books")

		var book Book
		err := c.Find(bson.M{"isbn": isbn}).One(&book)
		if err != nil {
			ErrorWithJSON(w, "数据库错误", http.StatusInternalServerError)
			log.Println("查找isbn的书失败: ", err)
			return
		}

		if book.ISBN == "" {
			ErrorWithJSON(w, "书不存在", http.StatusNotFound)
			return
		}

		respBody, err := json.MarshalIndent(book, "", "  ")
		if err != nil {
			log.Fatal(err)
		}

		ResponseWithJSON(w, respBody, http.StatusOK)
	}
}

执行程序

go run  mongdb-select.go

继续用postman测试接口

 ​

2.3  修改单书籍接口

新建go文件mongdb-update.go，键入以下代码

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	"goji.io"
	"goji.io/pat"
	"gopkg.in/mgo.v2"
    "gopkg.in/mgo.v2/bson"
)

func ErrorWithJSON(w http.ResponseWriter, message string, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	fmt.Fprintf(w, "{message: %q}", message)
}

func ResponseWithJSON(w http.ResponseWriter, json []byte, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	w.Write(json)
}

type Book struct {
	ISBN    string   `json:"isbn"`
	Title   string   `json:"title"`
	Authors []string `json:"authors"`
	Price   string   `json:"price"`
}

func main() {
	session, err := mgo.Dial("mongodb://root:87654321@127.0.0.1:27017/douyin")
	if err != nil {
		panic(err)
	}
	defer session.Close()

	session.SetMode(mgo.Monotonic, true)
	ensureIndex(session)

	mux := goji.NewMux()
    mux.HandleFunc(pat.Put("/books/:isbn"), updateBook(session))	 
    http.ListenAndServe("192.168.8.200:8888", mux)
}

func ensureIndex(s *mgo.Session) {
	session := s.Copy()
	defer session.Close()

	c := session.DB("douyin").C("books")

	index := mgo.Index{
		Key:        []string{"isbn"},
		Unique:     true,
		DropDups:   true,
		Background: true,
		Sparse:     true,
	}
	err := c.EnsureIndex(index)
	if err != nil {
		panic(err)
	}
}


func updateBook(s *mgo.Session) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		session := s.Copy()
		defer session.Close()

		isbn := pat.Param(r, "isbn")

		var book Book
		decoder := json.NewDecoder(r.Body)
		err := decoder.Decode(&book)
		if err != nil {
			ErrorWithJSON(w, "Incorrect body", http.StatusBadRequest)
			return
		}

		c := session.DB("douyin").C("books")

		err = c.Update(bson.M{"isbn": isbn}, &book)
		if err != nil {
			switch err {
			default:
				ErrorWithJSON(w, "Database error", http.StatusInternalServerError)
				log.Println("Failed update book: ", err)
				return
			case mgo.ErrNotFound:
				ErrorWithJSON(w, "Book not found", http.StatusNotFound)
				return
			}
		}

		w.WriteHeader(http.StatusNoContent)
	}
}

执行以上程序 

go run  mongdb-update.go

 postman继续测试

​

再此查询isbn为1234567890的信息

​

2.4  查询所有书籍接口

新建go文件mongdb-all.go，键入以下代码

package main

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"

	"goji.io"
	"goji.io/pat"
	"gopkg.in/mgo.v2"
         "gopkg.in/mgo.v2/bson"
)

func ErrorWithJSON(w http.ResponseWriter, message string, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	fmt.Fprintf(w, "{message: %q}", message)
}

func ResponseWithJSON(w http.ResponseWriter, json []byte, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	w.Write(json)
}

type Book struct {
	ISBN    string   `json:"isbn"`
	Title   string   `json:"title"`
	Authors []string `json:"authors"`
	Price   string   `json:"price"`
}

func main() {
	session, err := mgo.Dial("mongodb://root:87654321@127.0.0.1:27017/douyin")
	if err != nil {
		panic(err)
	}
	defer session.Close()

	session.SetMode(mgo.Monotonic, true)
	ensureIndex(session)

	mux := goji.NewMux()
    	mux.HandleFunc(pat.Get("/books"), allBooks(session))

    http.ListenAndServe("192.168.8.200:8889", mux)
}

func ensureIndex(s *mgo.Session) {
	session := s.Copy()
	defer session.Close()

	c := session.DB("douyin").C("books")

	index := mgo.Index{
		Key:        []string{"isbn"},
		Unique:     true,
		DropDups:   true,
		Background: true,
		Sparse:     true,
	}
	err := c.EnsureIndex(index)
	if err != nil {
		panic(err)
	}
}

func allBooks(s *mgo.Session) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		session := s.Copy()
		defer session.Close()

		c := session.DB("douyin").C("books")

		var books []Book
		err := c.Find(bson.M{}).All(&books)
		if err != nil {
			ErrorWithJSON(w, "Database error", http.StatusInternalServerError)
			log.Println("Failed get all books: ", err)
			return
		}

		respBody, err := json.MarshalIndent(books, "", "  ")
		if err != nil {
			log.Fatal(err)
		}

		ResponseWithJSON(w, respBody, http.StatusOK)
	}
}

运行该程序

go run  mongdb-all.go

打开postman或浏览器

​

2.5 删除单书籍接口

新建go文件mongdb-delete.go（根据isbn编号），键入以下代码

package main

import (
	"fmt"
	"log"
	"net/http"

	"goji.io"
	"goji.io/pat"
	"gopkg.in/mgo.v2"
         "gopkg.in/mgo.v2/bson"
)

func ErrorWithJSON(w http.ResponseWriter, message string, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	fmt.Fprintf(w, "{message: %q}", message)
}

func ResponseWithJSON(w http.ResponseWriter, json []byte, code int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	w.Write(json)
}

type Book struct {
	ISBN    string   `json:"isbn"`
	Title   string   `json:"title"`
	Authors []string `json:"authors"`
	Price   string   `json:"price"`
}

func main() {
	session, err := mgo.Dial("mongodb://root:87654321@127.0.0.1:27017/douyin")
	if err != nil {
		panic(err)
	}
	defer session.Close()

	session.SetMode(mgo.Monotonic, true)
	ensureIndex(session)

	mux := goji.NewMux()
    	mux.HandleFunc(pat.Delete("/books/:isbn"), deleteBook(session))

    http.ListenAndServe("192.168.8.200:8889", mux)
}

func ensureIndex(s *mgo.Session) {
	session := s.Copy()
	defer session.Close()

	c := session.DB("douyin").C("books")

	index := mgo.Index{
		Key:        []string{"isbn"},
		Unique:     true,
		DropDups:   true,
		Background: true,
		Sparse:     true,
	}
	err := c.EnsureIndex(index)
	if err != nil {
		panic(err)
	}
}
func deleteBook(s *mgo.Session) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		session := s.Copy()
		defer session.Close()

		isbn := pat.Param(r, "isbn")

		c := session.DB("douyin").C("books")

		err := c.Remove(bson.M{"isbn": isbn})
		if err != nil {
			switch err {
			default:
				ErrorWithJSON(w, "Database error", http.StatusInternalServerError)
				log.Println("Failed delete book: ", err)
				return
			case mgo.ErrNotFound:
				ErrorWithJSON(w, "Book not found", http.StatusNotFound)
				return
			}
		}

		w.WriteHeader(http.StatusNoContent)
	}
}

执行以上程序

go run  mongdb-delete.go

用postman测试删除

 ​

然后去数据库查看是否还有该isbn为1234567890的书籍

 ​

 

最后加上一点，mongodb和其他数据库mysql、postgresql一样面临数据多需要分页的情况，类比2012年做的车辆GPS+3G视频监控调度系统（每辆车只要一启动开火，就会产生大量的视频数据，一运行，就会产生很多的gps数据上传到数据中心，可以通过系统实时查看车上的视频情况和运行轨迹），被央视广泛宣传推广。数据量不是一般的多！！！视频数据还好，一会月没有盗窃案件事件就删除了（那时没有大数据的理念，也没有用人工智能训练数据的初衷，并没有存下来，且存储和内存还是很贵的，不像现在服务器几十上百G内存、存储空间以T为单位），可每辆车每天的gps数据却是长久保存的，要是哪天想回看在地图上的历史轨迹，就要从很多数据里检索，有点像后来衍生出的ofo、摩拜、滴滴和其他共享车平台。

附代码已上传github： https://github.com/dongguangming/golang-learn/tree/master/go-mongodb

 

参考:

1. The myth of NoSQL (vs. RDBMS) “joins dont scale”

2. How To Install MongoDB on CentOS 7 https://www.digitalocean.com/community/tutorials/how-to-install-mongodb-on-centos-7

3. mongodb设置密码 https://cloud.tencent.com/developer/article/1401326

4.  MongoDB Configuration File Options https://docs.mongodb.com/manual/reference/configuration-options/#security-options

5. The mongo Shell  https://docs.mongodb.com/manual/mongo/

6.  How To Build Microservice With MongoDB In Golang  https://goinbigdata.com/how-to-build-microservice-with-mongodb-in-golang/

7. How to paginate with MongoDB https://rabbitoncode.com/big-data/2019/10/11/pagination-mongo/

8. API Paging Built The Right Way https://engineering.mixmax.com/blog/api-paging-built-the-right-way/

9. Golang, Gin & MongoDB – Building microservices easily https://blog.codecentric.de/en/2020/04/golang-gin-mongodb-building-microservices-easily/

10. Paging with the Bucket Pattern - Part 1  https://www.mongodb.com/blog/post/paging-with-the-bucket-pattern--part-1

11. 海量数据的分页怎么破 https://mongoing.com/archives/25469

12. Pagination for MSSQL & MongoDB https://piotrgankiewicz.com/2016/04/19/pagination-for-mssql-mongodb/