Go gRPC进阶

前言

上篇介绍了go-grpc-middleware的grpc_zap、grpc_auth和grpc_recovery使用，本篇将介绍grpc_validator，它可以对gRPC数据的输入和输出进行验证。

创建proto文件，添加验证规则

这里使用第三方插件go-proto-validators自动生成验证规则。

go get github.com/mwitkow/go-proto-validators

1.新建simple.proto文件

1syntax = "proto3";
2
3package proto;
4
5import "github.com/mwitkow/go-proto-validators/validator.proto";
6
7message InnerMessage {
8  // some_integer can only be in range (1, 100).
9  int32 some_integer = 1 [(validator.field) = {int_gt: 0, int_lt: 100}];
10  // some_float can only be in range (0;1).
11  double some_float = 2 [(validator.field) = {float_gte: 0, float_lte: 1}];
12}
13
14message OuterMessage {
15  // important_string must be a lowercase alpha-numeric of 5 to 30 characters (RE2 syntax).
16  string important_string = 1 [(validator.field) = {regex: "^[a-z]{2,5}$"}];
17  // proto3 doesn't have `required`, the `msg_exist` enforces presence of InnerMessage.
18  InnerMessage inner = 2 [(validator.field) = {msg_exists : true}];
19}
20
21service Simple{
22  rpc Route (InnerMessage) returns (OuterMessage){};
23}

代码import "github.com/mwitkow/go-proto-validators/validator.proto"，文件validator.proto需要import "google/protobuf/descriptor.proto";包，不然会报错。

google/protobuf地址：https://github.com/protocolbuffers/protobuf/blob/master/src/google/protobuf/descriptor.proto。

把src文件夹中的protobuf目录下载到GOPATH目录下。

2.编译simple.proto文件

go get github.com/mwitkow/go-proto-validators/protoc-gen-govalidators

指令编译：protoc --govalidators_out=. --go_out=plugins=grpc:./ ./simple.proto

或者使用VSCode-proto3插件，第一篇有介绍。只需要添加"--govalidators_out=."即可。

1    // vscode-proto3插件配置
2    "protoc": {
3        // protoc.exe所在目录
4        "path": "C:\\Go\\bin\\protoc.exe",
5        // 保存时自动编译
6        "compile_on_save": true,
7        "options": [
8            // go编译输出指令
9            "--go_out=plugins=grpc:.",
10            "--govalidators_out=."
11        ]
12    },

编译完成后，自动生成simple.pb.go和simple.validator.pb.go文件，simple.pb.go文件不再介绍，我们看下simple.validator.pb.go文件。

1// Code generated by protoc-gen-gogo. DO NOT EDIT.
2// source: go-grpc-example/9-grpc_proto_validators/proto/simple.proto
3
4package proto
5
6import (
7	fmt "fmt"
8	math "math"
9	proto "github.com/golang/protobuf/proto"
10	_ "github.com/mwitkow/go-proto-validators"
11	regexp "regexp"
12	github_com_mwitkow_go_proto_validators "github.com/mwitkow/go-proto-validators"
13)
14
15// Reference imports to suppress errors if they are not otherwise used.
16var _ = proto.Marshal
17var _ = fmt.Errorf
18var _ = math.Inf
19
20func (this *InnerMessage) Validate() error {
21	if !(this.SomeInteger > 0) {
22		return github_com_mwitkow_go_proto_validators.FieldError("SomeInteger", fmt.Errorf(`value '%v' must be greater than '0'`, this.SomeInteger))
23	}
24	if !(this.SomeInteger < 100) {
25		return github_com_mwitkow_go_proto_validators.FieldError("SomeInteger", fmt.Errorf(`value '%v' must be less than '100'`, this.SomeInteger))
26	}
27	if !(this.SomeFloat >= 0) {
28		return github_com_mwitkow_go_proto_validators.FieldError("SomeFloat", fmt.Errorf(`value '%v' must be greater than or equal to '0'`, this.SomeFloat))
29	}
30	if !(this.SomeFloat <= 1) {
31		return github_com_mwitkow_go_proto_validators.FieldError("SomeFloat", fmt.Errorf(`value '%v' must be lower than or equal to '1'`, this.SomeFloat))
32	}
33	return nil
34}
35
36var _regex_OuterMessage_ImportantString = regexp.MustCompile(`^[a-z]{2,5}$`)
37
38func (this *OuterMessage) Validate() error {
39	if !_regex_OuterMessage_ImportantString.MatchString(this.ImportantString) {
40		return github_com_mwitkow_go_proto_validators.FieldError("ImportantString", fmt.Errorf(`value '%v' must be a string conforming to regex "^[a-z]{2,5}$"`, this.ImportantString))
41	}
42	if nil == this.Inner {
43		return github_com_mwitkow_go_proto_validators.FieldError("Inner", fmt.Errorf("message must exist"))
44	}
45	if this.Inner != nil {
46		if err := github_com_mwitkow_go_proto_validators.CallValidatorIfExists(this.Inner); err != nil {
47			return github_com_mwitkow_go_proto_validators.FieldError("Inner", err)
48		}
49	}
50	return nil
51}

里面自动生成了message中属性的验证规则。

把grpc_validator验证拦截器添加到服务端

1grpcServer := grpc.NewServer(cred.TLSInterceptor(),
2	grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
3			grpc_validator.StreamServerInterceptor(),
4	        grpc_auth.StreamServerInterceptor(auth.AuthInterceptor),
5			grpc_zap.StreamServerInterceptor(zap.ZapInterceptor()),
6			grpc_recovery.StreamServerInterceptor(recovery.RecoveryInterceptor()),
7		)),
8		grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
9		    grpc_validator.UnaryServerInterceptor(),
10		    grpc_auth.UnaryServerInterceptor(auth.AuthInterceptor),
11			grpc_zap.UnaryServerInterceptor(zap.ZapInterceptor()),
12            grpc_recovery.UnaryServerInterceptor(recovery.RecoveryInterceptor()),
13		)),
14	)

运行后，当输入数据验证失败后，会有以下错误返回

Call Route err: rpc error: code = InvalidArgument desc = invalid field SomeInteger: value '101' must be less than '100'

其他类型验证规则设置

enum验证

1syntax = "proto3";
2package proto;
3import "github.com/mwitkow/go-proto-validators/validator.proto";
4
5message SomeMsg {
6  Action do = 1 [(validator.field) = {is_in_enum : true}];
7}
8
9enum Action {
10  ALLOW = 0;
11  DENY = 1;
12  CHILL = 2;
13}

UUID验证

1syntax = "proto3";
2package proto;
3import "github.com/mwitkow/go-proto-validators/validator.proto";
4
5message UUIDMsg {
6  // user_id must be a valid version 4 UUID.
7  string user_id = 1 [(validator.field) = {uuid_ver: 4, string_not_empty: true}];
8}

总结

go-grpc-middleware中grpc_validator集成go-proto-validators，我们只需要在编写proto时设好验证规则，并把grpc_validator添加到gRPC服务端，就能完成gRPC的数据验证，很简单也很方便。

教程源码地址：https://github.com/Bingjian-Zhu/go-grpc-example