Golang

Cap’n proto 号称是比protobuff更快的proto语言。官网截图 Cap’n Proto is an insanely fast data interchange format and capability-based RPC system. Think JSON, except binary. Or think Protocol Buffers, except faster. In fact, in benchmarks, Cap’n Proto is INFINITY TIMES faster than Protocol Buffers. 协议特性 Cap’n Proto’s RPC protocol has the following notable features. Since the protocol is complicated, the feature set has been divided into numbered “levels”, so that implementations may declare which features they have covered by advertising a level number....

Go是一门强类型的语言，在大多数情况下，申明一个变量、函数、struct都是直截了当的。在大多数情况下，这些都是够用的，但有时你想在程序运行中来动态扩展程序的信息，也许你想把文件或网络请求中的数据映射到一个变量中;也许你想建立一个能处理不同类型的工具(虽然Go1.18有了泛型)。在这些情况下，你需要使用反射。反射使你有能力在运行时检查、修改和创建变量、函数和结构的能力。 反射的核心 图片转自 Go 语言设计与实现 反射的三大核心是*Types, Kinds, Values,下面将围绕这三个方面来进行讲解。 我们先定义一个struct对象。 type User struct { Name string Age int } 类型Types 通过反射获取类型 u := User{ Name: "czyt", Age: 18, } uptr := &u ot := reflect.TypeOf(u) otptr := reflect.TypeOf(uptr) log.Println(ot.Name()) // 打印 User log.Println(otptr.Name()) // 打印 空 通过调用Name()方法返回类型的名称，某些类型，如切片或指针，没有名称，此方法返回一个空字符串。 种类Kinds Kind通过调用Kind()得来。 u := User{ Name: "czyt", Age: 18, } uptr := &u ot := reflect.TypeOf(u) otptr := reflect.TypeOf(uptr) log.Println(ot.Kind()) // 输出 struct log.Println(otptr.Kind()) // 输出 ptr Kind() 返回的是kind类型的枚举。...

(本文大部分内容根据官方文档翻译而来) 环境准备 golang 1.10+ mongodb mgm 模型定义 定义 定义模型 type Book struct { // DefaultModel adds _id, created_at and updated_at fields to the Model mgm.DefaultModel `bson:",inline"` Name string `json:"name" bson:"name"` Pages int `json:"pages" bson:"pages"` } func NewBook(name string, pages int) *Book { return &Book{ Name: name, Pages: pages, } } mgm 在创建表时会自动检测Model生成的Collection名称 book:=Book{} // Print your model collection name. collName := mgm.CollName(&book) fmt.Println(collName) // 打印: books 如果要自定义生成Collection的名称。需要实现CollectionNameGetter接口。 func (model *Book) CollectionName() string { return "my_books" } // mgm return "my_books" collection coll:=mgm....

TL;DR 环境准备 mongoDB 预备知识 MongoDB常见的数据类型 数据类型 示例 说明 Null {"x" : null} Boolean {"x" : true} Number {"x" : 3.14} {"x" : 3} {"x" : NumberInt("3")} {"x" : NumberLong("3")} 默认64位浮点数，整数需要使用NumberInt和NumberLong String {"x" : "foobar"} 编码格式为UTF-8 Date {"x" : new Date()} 64位时间戳(从January 1, 1970)，不存时区。通过new Date()进行调用。 Regular expression {"x" : /foobar/i} javascript 正则 Array {"x" : ["a", "b", "c"]} Embedded document {"x" : {"foo" : "bar"}} Object ID {"x" : ObjectId()} 文档12字节的ID Binary data 一个任意字节的字符串。是保存非UTF-8字符串到数据库的唯一方法。 Code {"x" : function() { /* ....

代码 package main import ( "fmt" "syscall" ) func main() { l, _ := ListenNetlink() for { msgs, err := l.ReadMsgs() if err != nil { fmt.Println("Could not read netlink: %s", err) } for _, m := range msgs { if IsNewAddr(&m) { fmt.Println("New Addr") } if IsDelAddr(&m) { fmt.Println("Del Addr") } } } } type NetlinkListener struct { fd int sa *syscall.SockaddrNetlink } func ListenNetlink() (*NetlinkListener, error) { groups := (1 << (syscall....

缘起 来自于一段prometheus代码 type stripeLock struct { sync.RWMutex // Padding to avoid multiple locks being on the same cache line. _ [40]byte } 简单地讲就是因为CPU读取数据的缓存机制问题，可能导致性能上的不同差异。参考资料见后文。 常见类型的内存占用大小（Go101）： Kinds of Types Value Size Required by Go Specification bool 1 byte not specified int8, uint8 (byte) 1 byte 1 byte int16, uint16 2 bytes 2 bytes int32 (rune), uint32, float32 4 bytes 4 bytes int64, uint64, float64, complex64 8 bytes 8 bytes complex128 16 bytes 16 bytes int, uint 1 word architecture dependent, 4 bytes on 32-bit architectures and 8 bytes on 64-bit architectures uintptr 1 word large enough to store the uninterpreted bits of a pointer value string 2 words not specified pointer (safe or unsafe) 1 word not specified slice 3 words not specified map 1 word not specified channel 1 word not specified function 1 word not specified interface 2 words not specified struct (the sum of sizes of all fields) + (the number of padding bytes) the size of a struct type is zero if it contains no fields that have a size greater than zero array (element value size) * (array length) the size of an array type is zero if its element type has zero size 参考 https://medium....

Csharp 安装Grpc.tools https://www.nuget.org/packages/Grpc.Tools/ 下载解压 nupkg文件（改扩展名为zip），也可以使用附件的7z包 解压 找到tools中对应系统架构的软件，设置下环境变量，让系统可以找到就行。 Linux 需要创建一个符号链接 ln -s `which grpc_csharp_plugin` /usr/bin/protoc-gen-grpc-csharp 修改Kratos项目的Make文件 在api这个make任务中添加下面内容 --csharp_out=./api/pipe/v1 \ --grpc-csharp_out=./api/pipe/v1 \ 完整内容为 .PHONY: api # generate api proto api: protoc --proto_path=./api \ --proto_path=./third_party \ --go_out=paths=source_relative:./api \ --go-http_out=paths=source_relative:./api \ --go-grpc_out=paths=source_relative:./api \ --csharp_out=./api/pipe/v1 \ --grpc-csharp_out=./api/pipe/v1 \ --openapi_out==paths=source_relative:. \ 参考 https://github.com/grpc/grpc/blob/master/src/csharp/BUILD-INTEGRATION.md 📎tools.7z Python 安装必要包 pip install grpclib protobuf 查询路径 which protoc-gen-grpclib_python 或者 which protoc-gen-python_grpc我这里返回信息如下： ➜ czyt which protoc-gen-grpclib_python /usr/sbin/protoc-gen-grpclib_python 如法炮制，创建软链接 ln -s /usr/sbin/protoc-gen-grpclib_python /usr/sbin/protoc-gen-grpc_python 修改Makefile 添加下面的内容,再执行make api生成api即可。 --python_out=....

下载 官方下载 https://go.dev/dl/ Google 香港镜像 Golang Downloads Mirrors 更多请参考 Thanks Mirror 环境设置 设置proxy go env -w GOPROXY=https://goproxy.io,https://goproxy.cn,direct 安装相关工具 进程工具 goreman go install github.com/mattn/goreman@latest 框架Cli kratos go install github.com/go-kratos/kratos/cmd/kratos/v2@latest wire go install github.com/google/wire/cmd/wire@latest ent go install entgo.io/ent/cmd/ent@latest entimport go install ariga.io/entimport/cmd/entimport@latest entproto go install entgo.io/contrib/entproto/cmd/entproto@latest 代码Lint golangci-lint go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest golines go install github.com/segmentio/golines@latest Go into the Goland settings and click “Tools” -> “File Watchers” then click the plus to create a new file watcher Set the following properties and confirm by clicking OK: Name: golines File type: Go files Scope: Project Files Program: golines Arguments: $FilePath$ -w Output paths to refresh: $FilePath$ gofumpt go install mvdan....

下载protoc，打开链接 下载后将对应的文件解压到gopath的bin目录。 下载protoc的golang插件。下载地址 链接 下载后放在protoc的同级目录（需要改扩展名为exe） 测试，定义一个Proto syntax = "proto3"; option go_package = ".;hello"; package main; message String { string value = 1; } 然后执行命令 protoc hello.proto --go_out=. ,大功告成，生成的文件内容如下： // Code generated by protoc-gen-go. DO NOT EDIT. // versions: // protoc-gen-go v1.24.0-devel // protoc v3.12.3 // source: hello.proto package hello import ( proto "github.com/golang/protobuf/proto" protoreflect "google.golang.org/protobuf/reflect/protoreflect" protoimpl "google.golang.org/protobuf/runtime/protoimpl" reflect "reflect" sync "sync" ) const ( // Verify that this generated code is sufficiently up-to-date....

package main import ( "fmt" "net/http" ) func main() { http.HandleFunc("/favicon.ico", favicon) http.HandleFunc("/", hello) fmt.Printf("listening on http://localhost:8000/\n") http.ListenAndServe("localhost:8000", nil) } func favicon(w http.ResponseWriter, r *http.Request) { fmt.Printf("%s\n", r.RequestURI) w.Header().Set("Content-Type", "image/x-icon") w.Header().Set("Cache-Control", "public, max-age=7776000") fmt.Fprintln(w, "data:image/x-icon;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQEAYAAABPYyMiAAAABmJLR0T///////8JWPfcAAAACXBIWXMAAABIAAAASABGyWs+AAAAF0lEQVRIx2NgGAWjYBSMglEwCkbBSAcACBAAAeaR9cIAAAAASUVORK5CYII=\n") } func hello(w http.ResponseWriter, r *http.Request) { fmt.Printf("%s\n", r.RequestURI) fmt.Fprintln(w, "Hello, World!") }