gin

https://github.com/gin-gonic/gin

Gin is a HTTP web framework written in Go (Golang). It features a Martini-like API with much better performance -- up to 40 times faster. If you need smashing performance, get yourself some Gin.

startup a gin server

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// new engine
engine := gin.New()
engine.MaxMultipartMemory = 100 << 20 // limit file upload size to 100M
engine.Use(gin.Logger(), gin.Recovery()) // add middleware
engine.Use(other_middleware.Constructor()) // add custom middleware

// healthz
engine.GET("/healthz", func (ctx *gin.Context) {
    ctx.String(http.StatusOK, "SERVING")
})

// router
apiGroup := engine.Group("/api-name")
apiGroup.Use(some_middleware.Constructor())

apiGroup.GET("/get", funcGet)
apiGroup.POST("/post", funcPost)
apiGroup.PUT("/put", funcPut)

// start up server
gwServer := &http.Server{
    Addr: "ip:port", // you may want to bind on specify ip, or all ip if you pass ':80'
    Handler: engine,
}

listener, err := net.listen("tcp", gwServer.Addr)
if err != nil {
    panic("unable to listen on address")
}

if NoTls {
    if err := gwServer.Serve(listener); err != nil {
        if errors.Is(err, http.ErrServerClosed) {
            // server close gracefully
        } else {
            // log and panic
            panic("server shutdown")
        }
    }
}

if Tls {
    if err := gwServer.ServeTLS(listener, CertPath, KeyPath); err != nil {
        if errors.Is(err, http.ErrServerClosed) {
            // server close gracefully
        } else {
            // log and panic
            panic("server shutdown")
        }
    } 
}

serve swagger docs

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engine.StaticFS("/docs/", http.FS(swaggerDocEmbedFs))
engine.GET(
    "/swagger/*any",
    ginSwagger.WrapHandler(
        swaggerFiles.Handler,
        ginSwagger.URL("/docs/path/to/swagger/doc.json")
    ),
)

常用命令

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# install tool
brew install kubectx
brew install kubectl

# alais
alais k="kubectl"
alais kx="kubectx"
alais kn="kubens"

k get pods
k get ns |grep ns-name
k get service
k port-forward --address 10.0.0.1 service/name -n namespace/name 80:80 8080:8080

# merge multi config
export KUBECONFIG=~/.kube/config:./kube-config-1.yaml kubectx config view --flatten > ~/.kube/config

# list pods
k get pods --all-namespaces |pod-name

# log pod
k logs -f pod-name -n namespace-name

# scale
k scale --replicas=3 pod-name

# context & namespace
kx context-name
kn namespace-name

cloud port forward with supervisor

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brew install supervisor
alais sctrl="supervisorctl"

sctl reload
sctl [start, stop, restart] group-name:\*
sctl status

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[program:service-1]
command=/usr/local/bin/kubectl port-forward --address 10.0.0.1 pod-name -n ns-name 80:80
redirect_stderr=true
stdout_logfile=/usr/local/var/log/%(program_name)s.log
stdout_logfile_maxbytes=1MB
autostart=false

[program:service-2]
command=/usr/local/bin/kubectl port-forward --address 10.0.0.2 pod-name -n ns-name 80:80
redirect_stderr=true
stdout_logfile=/usr/local/var/log/%(program_name)s.log
stdout_logfile_maxbytes=1MB
autostart=false

[group:group-name]
programs=service-1,service-2

Ref

kubectl 备忘单 https://kubernetes.io/zh/docs/reference/kubectl/cheatsheet/

Git是目前最流行的版本管理系统，github.com也是当前最大的交友论坛，学习并使用Git已经是程序员的基本要求。

安装

命令行版本

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brew install git
brew install tig

图形界面
SourceTree https://www.sourcetreeapp.com/
Github Desktop https://desktop.github.com/

配置使用

修改~/.gitconfig文件

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[user]
    name = ubuntu
    email = ubuntu@utunbu.com
    signingkey = your-sign-key
[alias]
    co = checkout
    br = branch
    ci = commit -S -m
    st = status
    last = log -1 HEAD
    un = update-index --assume-unchanged
    noun= update-index --no-assume-unchanged
    ignored = !git ls-files -v | grep "^[[:lower:]]"
[credential]
    helper = store
[commit]
    template = /ubuntu/.stCommitMsg
    gpgsign = true
[url "https://github.com/"]
    insteadOf = ssh://git@github.com/

修改~/.gitignore_global

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*~
*.swp
*.swo
*.swn
.DS_Store

常用命令

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git clone https://git.ubuntu.com/ubuntu.git
git st
git ci -a -m'comment message'

# reset local change, HARD
git reset --hard

# amend into last commit
git commit --amend

# merge some-br into current branch, squash
git merge --squash some-br

# restore file
git restore path/to/some/file

# checkout remote branch
git fetch origin/test
git checkout origin/test
git checkout -b test origin/test

# stash
git stash
git stash pop

# git url redirect
git config --global url."https://$(user):$(token)@github.com/username".insteadOf "https://github.com/username"
git config --global url."https://api:xxx@github.com/".insteadOf "git@github.com:"

rebase

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git rebase -i HEAD~n

进本交互编辑界面，提示如下：

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pick f7f3f6d changed my name a bit
pick 310154e updated README formatting and added blame
pick a5f4a0d added cat-file

# Rebase 710f0f8..a5f4a0d onto 710f0f8
#
# Commands:
#  p, pick = use commit
#  e, edit = use commit, but stop for amending
#  s, squash = use commit, but meld into previous commit
#
# If you remove a line here THAT COMMIT WILL BE LOST.
# However, if you remove everything, the rebase will be aborted.

修改后边的两个pick为squash,可以将这三个commit合为一个提交：

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pick f7f3f6d changed my name a bit
squash 310154e updated README formatting and added blame
squash a5f4a0d added cat-file

# Rebase 710f0f8..a5f4a0d onto 710f0f8
#
# Commands:
#  p, pick = use commit
#  e, edit = use commit, but stop for amending
#  s, squash = use commit, but meld into previous commit
#
# If you remove a line here THAT COMMIT WILL BE LOST.
# However, if you remove everything, the rebase will be aborted.

netrc auto login

*** AS YOU MAY KNOWN, IT’S VERY DANGEROUS ***

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touch ~/.netrc

machine github.com
login github-user-name
password user-token

machine gitlab.com
login gitlab-user-name
password gitlab-user-token

GPG Sign

Download GPG Suite: https://gpgtools.org/

1. Open GPG Keychain
2. Click New to and follow instrctions to generate a new GPG key
3. Select the key you want to export and click Export
4. Copy the content of exported public key, add to Github or Gitlab, if you prefer to use terminal: gpg --armor --export pub <KEY ID>
5. Config Git to use your sign key id
   • execute gpg --list-secret-keys --keyid-format=long
   • copy sign key id from sec ed20000/this-is-you-sign-key 2099-01-01 [SC]
   • execute git config --global user.signingkey <KEY ID>
   • force git to sign all commit with git config --global commit.gpgsign true

With Sourcetree GUI:

• open preferences, under Advenced set GPG Program, with GPG Suite it’s /usr/local/MacGPG2/bin
• for each repository, open Repository -> Repository Setting, under Security section, enable GPG sign and select the right sign-key

安装

Docker Desktop: https://www.docker.com/products/docker-desktop/
Docker Hub: https://hub.docker.com/

docker

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# docker image
docker pull postgres
docker image ls
docker image rm image-name # remove image-name
docker rmi image-name # remove image-name
docker image inspect image-name

# start container
docker run --name mypgsql -p 5432:5432 -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=password -e POSTGRES_HOST_AUTH_METHOD=password -d postgres

# maintain
docker ps
docker stats CONTAINER
docker logs -f CONTAINER
dokcer exec -it CONTAINER /bin/sh
docker top CONTAINER

# docker system
docker system df
docker builder prune # clean build cache
docker container prune # clean unused container

# build image
docker build -t tagname -f path/to/Dockerfile .

# registry
docker login
docker login registry.gitlab.com

# network
docker network create -d bridge test-net
docker run -itd --name test1 --network test-net ubuntu /bin/bash
docker run -itd --name test2 --network test-net ubuntu /bin/bash

# save
docker save busybox > busybox.tar
docker save -o fedora-latest.tar fedora:latest
docker save myimage:latest | gzip > myimage_latest.tar.gz

# export
docker export 1e560fca3906 > ubuntu.tar
cat docker/ubuntu.tar | docker import - test/ubuntu:v1

Dockerfile

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# this is builder
FROM golang:1.18.0-buster as builder
RUN apt-get update && apt-get install -y --no-install-recommends build-essential \
	&& rm -rf /var/lib/apt/lists/*

COPY . /sources
RUN cd /sources && make build

FROM debian:buster-slim
RUN apt-get update && apt-get install -y --no-install-recommends \
	ca-certificates libaio1 \
	&& rm -rf /var/lib/apt/lists/*

COPY --from=builder /sources/bin /usr/local/bin
COPY --from=builder /sources/resources /usr/local/resources

ENV SOME_ENV="env-value"

WORKDIR /usr/local

EXPOSE 80
EXPOSE 443

CMD ["/usr/local/bin/my-program"]

COPY

复制指令，从上下文目录中复制文件或者目录到容器里指定路径。

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COPY hom* /mydir/ COPY hom?.txt /mydir/

ADD 指令和 COPY 的使用格类似（同样需求下，官方推荐使用 COPY）。功能也类似，不同之处如下：

• ADD 的优点：在执行 <源文件> 为 tar 压缩文件的话，压缩格式为 gzip, bzip2 以及 xz 的情况下，会自动复制并解压到 <目标路径>。
• ADD 的缺点：在不解压的前提下，无法复制 tar 压缩文件。会令镜像构建缓存失效，从而可能会令镜像构建变得比较缓慢。具体是否使用，可以根据是否需要自动解压来决定。

CMD

类似于 RUN 指令，用于运行程序，但二者运行的时间点不同:

• CMD 在docker run 时运行
• RUN 是在 docker build

作用：为启动的容器指定默认要运行的程序，程序运行结束，容器也就结束。CMD 指令指定的程序可被 docker run 命令行参数中指定要运行的程序所覆盖。

注意：如果 Dockerfile 中如果存在多个 CMD 指令，仅最后一个生效。

ENV

设置环境变量，定义了环境变量，那么在后续的指令中，就可以使用这个环境变量。

格式：

ENV <key> <value> ENV <key1>=<value1> <key2>=<value2>...

ARG

构建参数，与 ENV 作用一致。不过作用域不一样。ARG 设置的环境变量仅对 Dockerfile 内有效。

docker-compose

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docker-compose -f file.yaml up -d
docker-compose -f file.yaml up service_name -d
docker-compose -f file.yaml image
docker-compose -f file.yaml down
docker-compose -f file.yaml [start, stop, restart] service_name
docker-compose -f file.yaml config |less

# remove deleted service
docker-compose -f file.yaml up -d --remove-orphans

Dockfile Example:

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version 3.7

networks:
  net-test:
    name: net-test

services:
  haproxy:
    networks:
      - net-test
    image: haproxy:latest
    command: |
      /usr/local/bin/haproxy
      --set-args-1:value-1
      --set-args-2:value-2
      --gprc:http://service_a:3366
    ports:
      - "10.0.0.1:1122:1122"
      - "10.0.0.1:1133:1133"
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: password
    volmes:
      - ./config:/usr/local/haproxy/config
    depends_on:
      - service_a
      - service_b

  service_a:
    ...

  service_b:
    ...

Network Alias

虚拟多个IP地址，将container内的端口绑到独立的IP上，以更真实的方式模拟发布环境。

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# up
ifconfig en0 alias 10.0.0.10 netmask 0xFFFFFFFF up
ifconfig en0 alias 10.0.0.11 netmask 0xFFFFFFFF up

# down
ifconfig en0 10.0.0.10 delete
ifconfig en0 10.0.0.11 delete

embed

GoDoc (https://pkg.go.dev/embed)

Package embed provides access to files embedded in the running Go program.

Go source files that import “embed” can use the //go:embed directive to initialize a variable of type string, []byte, or FS with the contents of files read from the package directory or subdirectories at compile time.

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import _ "embed"

//go:embed hello.txt
var s string
print(s)

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import _ "embed"

//go:embed hello.txt
var b []byte
print(string(b))

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import "embed"

//go:embed hello.txt
var f embed.FS
data, _ := f.ReadFile("hello.txt")
print(string(data))

• embeded files must under current folder. any file outside current folder will fail, for example /root/somefile will not work.
• "go:embed image/*" embeds all files under image/, including all file start with .dot and _underscore.
• * will not recursive sub folders. so .dotfile and _underscore will not be embeded with image/subfolder/ sub folder.
• "go:embed image/" or "go:embed image" embeds all file but ignored which start with .dot and _underscore.
• symbolic links are not followed.

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// embed multi files into a single filesystem
//go:embed image/* template/*
//go:embed html/index.html
var content embed.FS

//go:embed image template html/index.html
var content embed.FS

// embed files with space
//go:embed "he llo.txt"
var content embed.FS

Example with http-fileserver:

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import (
	"embed"
	"log"
	"net/http"
)

//go:embed internal/embedtest/testdata/*.txt
var content embed.FS

func main() {
	mutex := http.NewServeMux()
	mutex.Handle("/", http.FileServer(http.FS(content)))
	err := http.ListenAndServe(":8080", mutex)
	if err != nil {
		log.Fatal(err)
	}
}

embed filesystem need to access with full path from where embed declare, as follow:

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//go:embed pg/migration/init.sql
var PgMigrationFs embed.FS

you should access init.sql with full-path as pg/migration/init.sql.