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To build a well working microservice, we need lots of knowledges from different aspects.
-
basic functionalities
- concurrency control and rate limit, to avoid being brought down by unexpected inbound
- service discovery, make sure new or terminated nodes are detected asap
- load balancing, balance the traffic base on the throughput of nodes
- timeout control, avoid the nodes continue to process the timed out requests
- circuit breaker, load shedding, fail fast, protects the failure nodes to recover asap
-
advanced functionalities
- authorization, make sure users can only access their own data
- tracing, to understand the whole system and locate the specific problem quickly
- logging, collects data and helps to backtrace problems
- observability, no metrics, no optimization
For any point listed above, we need a long article to describe the theory and the implementation. But for us, the developers, it’s very difficult to understand all the concepts and make it happen in our systems. Although, we can use the frameworks that have been well served busy sites. go-zero is born for this purpose, especially for cloud-native microservice systems.
As well, we always adhere to the idea that prefer tools over conventions and documents. We hope to reduce the boilerplate code as much as possible, and let developers focus on developing the business related code. For this purpose, we developed the tool goctl
.
Let’s take the shorturl microservice as a quick example to demonstrate how to quickly create microservices by using go-zero. After finishing this tutorial, you’ll find that it’s so easy to write microservices!
For simplicity, the bookstore service only contains two functionalities, adding books and quering prices.
Writting this bookstore service is to demonstrate the complete flow of creating a microservice by using go-zero. But algorithms and detail implementations are quite simplified, and this bookstore service is not suitable for production use.
All modules with green background are generated, and will be enabled when necessary. The modules with red background are handwritten code, which is typically business logic code.
And now, let’s walk through the complete flow of quickly create a microservice with go-zero.
-
install etcd, mysql, redis
-
install protoc-gen-go
go get -u github.com/golang/protobuf/protoc-gen-go
-
install goctl
GO111MODULE=on go get -u github.com/tal-tech/go-zero/tools/goctl
-
create the working dir bookstore
-
in
bookstore
dir, executego mod init bookstore
to initialize `go.mod``
-
use goctl to generate
api/bookstore.api
goctl api -o bookstore.api
for simplicity, the leading
info
block is removed, and the code looks like:type ( addReq struct { book string `form:"book"` price int64 `form:"price"` } addResp struct { ok bool `json:"ok"` } ) type ( checkReq struct { book string `form:"book"` } checkResp struct { found bool `json:"found"` price int64 `json:"price"` } ) service bookstore-api { @server( handler: AddHandler ) get /add(addReq) returns(addResp) @server( handler: CheckHandler ) get /check(checkReq) returns(checkResp) }
the usage of
type
keyword is the same as that in go, service is used to define get/post/head/delete api requests, described below:- `service bookstore-api { defines the service name
@server
defines the properties that used in server sidehandler
defines the handler nameget /add(addReq) returns(addResp)
defines this is a GET request, the request parameters, and the response parameters
-
generate the code for API Gateway by using goctl
goctl api go -api bookstore.api -dir .
the generated file structure looks like:
api ├── bookstore.api // api definition ├── bookstore.go // main entrance ├── etc │ └── bookstore-api.yaml // configuration file └── internal ├── config │ └── config.go // configuration definition ├── handler │ ├── addhandler.go // implements addHandler │ ├── checkhandler.go // implements checkHandler │ └── routes.go // routes definition ├── logic │ ├── addlogic.go // implements AddLogic │ └── checklogic.go // implements CheckLogic ├── svc │ └── servicecontext.go // defines ServiceContext └── types └── types.go // defines request/response
-
start API Gateway service, listens on port 8888 by default
go run bookstore.go -f etc/bookstore-api.yaml
-
test API Gateway service
curl -i "http://localhost:8888/check?book=go-zero"
response like:
HTTP/1.1 200 OK Content-Type: application/json Date: Thu, 03 Sep 2020 06:46:18 GMT Content-Length: 25 {"found":false,"price":0}
You can see that the API Gateway service did nothing except returned a zero value. And let’s implement the business logic in rpc service.
-
you can modify
internal/svc/servicecontext.go
to pass dependencies if needed -
implement logic in package
internal/logic
-
you can use goctl to generate code for clients base on the .api file
-
till now, the client engineer can work with the api, don’t need to wait for the implementation of server side
-
under directory
rpc/add
createadd.proto
filegoctl rpc template -o add.proto
edit the file and make the code looks like:
syntax = "proto3"; package add; message addReq { string book = 1; int64 price = 2; } message addResp { bool ok = 1; } service adder { rpc add(addReq) returns(addResp); }
-
use goctl to generate the rpc code, execute the following command in
rpc/add
goctl rpc proto -src add.proto
the generated file structure looks like:
rpc/add ├── add.go // rpc main entrance ├── add.proto // rpc definition ├── adder │ ├── adder.go // defines how rpc clients call this service │ ├── adder_mock.go // mock file, for test purpose │ └── types.go // request/response definition ├── etc │ └── add.yaml // configuration file ├── internal │ ├── config │ │ └── config.go // configuration definition │ ├── logic │ │ └── addlogic.go // add logic here │ ├── server │ │ └── adderserver.go // rpc handler │ └── svc │ └── servicecontext.go // defines service context, like dependencies └── pb └── add.pb.go
just run it, looks like:
$ go run add.go -f etc/add.yaml
Starting rpc server at 127.0.0.1:8080...
you can change the listening port in file etc/add.yaml
.
-
under directory
rpc/check
createcheck.proto
filegoctl rpc template -o check.proto
edit the file and make the code looks like:
syntax = "proto3"; package check; message checkReq { string book = 1; } message checkResp { bool found = 1; int64 price = 2; } service checker { rpc check(checkReq) returns(checkResp); }
-
use goctl to generate the rpc code, execute the following command in
rpc/check
goctl rpc proto -src check.proto
the generated file structure looks like:
rpc/check ├── check.go // rpc main entrance ├── check.proto // rpc definition ├── checker │ ├── checker.go // defines how rpc clients call this service │ ├── checker_mock.go // mock file, for test purpose │ └── types.go // request/response definition ├── etc │ └── check.yaml // configuration file ├── internal │ ├── config │ │ └── config.go // configuration definition │ ├── logic │ │ └── checklogic.go // check logic here │ ├── server │ │ └── checkerserver.go // rpc handler │ └── svc │ └── servicecontext.go // defines service context, like dependencies └── pb └── check.pb.go
you can change the listening port in
etc/check.yaml
.we need to change the port in
etc/check.yaml
to8081
, because8080
is used byadd
service.just run it, looks like:
$ go run check.go -f etc/check.yaml Starting rpc server at 127.0.0.1:8081...
-
modify the configuration file
bookstore-api.yaml
, add the following:Add: Etcd: Hosts: - localhost:2379 Key: add.rpc Check: Etcd: Hosts: - localhost:2379 Key: check.rpc
automatically discover the add/check service by using etcd.
-
modify the file
internal/config/config.go
, add dependency on add/check service:type Config struct { rest.RestConf Add zrpc.RpcClientConf // manual code Check zrpc.RpcClientConf // manual code }
-
modify the file
internal/svc/servicecontext.go
, like below:type ServiceContext struct { Config config.Config Adder adder.Adder // manual code Checker checker.Checker // manual code } func NewServiceContext(c config.Config) *ServiceContext { return &ServiceContext{ Config: c, Adder: adder.NewAdder(zrpc.MustNewClient(c.Add)), // manual code Checker: checker.NewChecker(zrpc.MustNewClient(c.Check)), // manual code } }
passing the dependencies among services within ServiceContext.
-
modify the method
Add
in the fileinternal/logic/addlogic.go
, looks like:func (l *AddLogic) Add(req types.AddReq) (*types.AddResp, error) { // manual code start resp, err := l.svcCtx.Adder.Add(l.ctx, &adder.AddReq{ Book: req.Book, Price: req.Price, }) if err != nil { return nil, err } return &types.AddResp{ Ok: resp.Ok, }, nil // manual code stop }
by calling the method
Add
ofadder
to add books into bookstore. -
modify the file
internal/logic/checklogic.go
, looks like:func (l *CheckLogic) Check(req types.CheckReq) (*types.CheckResp, error) { // manual code start resp, err := l.svcCtx.Checker.Check(l.ctx, &checker.CheckReq{ Book: req.Book, }) if err != nil { return nil, err } return &types.CheckResp{ Found: resp.Found, Price: resp.Price, }, nil // manual code stop }
by calling the method
Check
ofchecker
to check the prices from the bookstore.
Till now, we’ve done the modification of API Gateway. All the manually added code are marked.
-
under bookstore, create the directory
rpc/model
:mkdir -p rpc/model
-
under the directory rpc/model create the file called
book.sql
, contents as below:CREATE TABLE `book` ( `book` varchar(255) NOT NULL COMMENT 'book name', `price` int NOT NULL COMMENT 'book price', PRIMARY KEY(`book`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
-
create DB and table
create database gozero;
source book.sql;
-
under the directory
rpc/model
execute the following command to genrate CRUD+cache code,-c
means usingredis cache
goctl model mysql ddl -c -src book.sql -dir .
you can also generate the code from the database url by using
datasource
subcommand instead ofddl
the generated file structure looks like:
rpc/model ├── bookstore.sql ├── bookstoremodel.go // CRUD+cache code └── vars.go // const and var definition
-
modify
rpc/add/etc/add.yaml
, add the following:DataSource: root:@tcp(localhost:3306)/gozero Table: book Cache: - Host: localhost:6379
you can use multiple redis as cache. redis node and cluster are both supported.
-
modify
rpc/add/internal/config.go
, like below:type Config struct { zrpc.RpcServerConf DataSource string // manual code Table string // manual code Cache cache.CacheConf // manual code }
added the configuration for mysql and redis cache.
-
modify
rpc/add/internal/svc/servicecontext.go
andrpc/check/internal/svc/servicecontext.go
, like below:type ServiceContext struct { c config.Config Model *model.BookModel // manual code } func NewServiceContext(c config.Config) *ServiceContext { return &ServiceContext{ c: c, Model: model.NewBookModel(sqlx.NewMysql(c.DataSource), c.Cache, c.Table), // manual code } }
-
modify
rpc/add/internal/logic/addlogic.go
, like below:func (l *AddLogic) Add(in *add.AddReq) (*add.AddResp, error) { // manual code start _, err := l.svcCtx.Model.Insert(model.Book{ Book: in.Book, Price: in.Price, }) if err != nil { return nil, err } return &add.AddResp{ Ok: true, }, nil // manual code stop }
-
modify
rpc/check/internal/logic/checklogic.go
, like below:func (l *CheckLogic) Check(in *check.CheckReq) (*check.CheckResp, error) { // manual code start resp, err := l.svcCtx.Model.FindOne(in.Book) if err != nil { return nil, err } return &check.CheckResp{ Found: true, Price: resp.Price, }, nil // manual code stop }
till now, we finished modifing the code, all the modified code is marked.
-
call add api
curl -i "http://localhost:8888/add?book=go-zero&price=10"
response like:
HTTP/1.1 200 OK Content-Type: application/json Date: Thu, 03 Sep 2020 09:42:13 GMT Content-Length: 11 {"ok":true}
-
call check api
curl -i "http://localhost:8888/check?book=go-zero"
response like:
HTTP/1.1 200 OK Content-Type: application/json Date: Thu, 03 Sep 2020 09:47:34 GMT Content-Length: 25 {"found":true,"price":10}
Because benchmarking the write requests depends on the write throughput of mysql, we only benchmarked the check api. We read the data from mysql and cache it in redis. For simplicity, I only check one book, because of cache, the effect is the same for multiple books.
Before benchmark, we need to change the max open files:
ulimit -n 20000
And change the log level to error, to avoid too many logs affect the benchmark. Add the following in every yaml file:
Log:
Level: error
as shown above, in my MacBook Pro, the QPS is like 30K+.
https://github.com/tal-tech/go-zero/tree/master/example/bookstore
We always adhere to prefer tools over conventions and documents.
go-zero is not only a framework, but also a tool to simplify and standardize the building of micoservice systems.
We not only keep the framework simple, but also encapsulate the complexity into the framework. And the developers are free from building the difficult and boilerplate code. Then we get the rapid development and less failure.
For the generated code by goctl, lots of microservice components are included, like concurrency control, adaptive circuit breaker, adaptive load shedding, auto cache control etc. And it’s easy to deal with the busy sites.
If you have any ideas that can help us to improve the productivity, tell me any time! 👏