<!doctype html><metacharset=utf-8><linkrel=preconnecthref=https://fonts.googleapis.com><linkrel=preconnecthref=https://fonts.gstatic.comcrossorigin><linkhref="https://fonts.googleapis.com/css2?family=Recursive:wght,CASL,MONO@300..800,0..1,0..1&display=swap"rel=stylesheet><linkrel=stylesheethref=styles.css><h1>Bootstrap Go</h1><p>It is hard to write bootstrap tool to quickly create Go service.<br>So I write this guide instead.<br>This is a quick checklist for me every damn time I need to write a Go service from scratch.<br>Also, this is my personal opinion, so feel free to comment.<h2>Structure</h2><pre><codeclass=language-txt>main.go
</code></pre><p>All business codes are inside <code>internal</code>.<br>Each business has a different directory (<code>business_1</code>, <code>business_2</code>).<p>Inside each business, there are 2 handlers: <code>http</code>, <code>grpc</code>:<ul><li><code>http</code> is for public APIs (Android, iOS,... are clients).<li><code>grpc</code> is for internal APIs (other services are clients).</ul><p>Inside each handler, there are usually 3 layers: <code>handler</code>, <code>service</code>, <code>repository</code>:<ul><li><code>handler</code> interacts directly with gRPC or REST using specific codes (cookies,...)<li><code>service</code> is where we write business/logic codes, and only business/logic codes is written here.<li><code>repository</code> is where we write codes which interacts with database/cache like MySQL, Redis, ...</ul><p><code>handler</code> must exist inside <code>grpc</code>, <code>http</code>.<br>But <code>service</code>, <code>repository</code>, <code>models</code> can exist directly inside <code>business</code> if both <code>grpc</code>, <code>http</code> has same business/logic.<h2>Do not repeat!</h2><p>If we have too many services, some of the logic will be overlapped.<p>For example, service A and service B both need to make POST call API to service C.<br>If service A and service B both have libs to call service C to do that API, we need to move the libs to some common pkg libs.<br>So in the future, service D which needs to call C will not need to copy libs to handle service C api but only need to import from common pkg libs.<p>Another bad practice is adapter service.<br>No need to write a new service if what we need is just common pkg libs.<h2>External libs</h2><h3>Don't use cli libs (<ahref=https://github.com/spf13/cobra>spf13/cobra</a>, <ahref=https://github.com/urfave/cli>urfave/cli</a>) just for Go service</h3><p>What is the point to pass many params (<code>--abc</code>, <code>--xyz</code>) when what we only need is start service?<p>In my case, service starts with only config, and config should be read from file or environment like <ahref=https://12factor.net/>The Twelve Factors</a> guide.<h3>Don't use <ahref=https://github.com/grpc-ecosystem/grpc-gateway>grpc-ecosystem/grpc-gateway</a></h3><p>Just don't.<p>Use <ahref=https://github.com/protocolbuffers/protobuf-go>protocolbuffers/protobuf-go</a>, <ahref=https://github.com/grpc/grpc-go>grpc/grpc-go</a> for gRPC.<p>Write 1 for both gRPC, REST sounds good, but in the end, it is not worth it.<h3>Don't use <ahref=https://github.com/uber/prototool>uber/prototool</a>, use <ahref=https://github.com/bufbuild/buf>bufbuild/buf</a></h3><p>prototool is deprecated, and buf can generate, lint, format as good as prototool.<h3>Use <ahref=https://github.com/gin-gonic/gin>gin-gonic/gin</a> for REST.</h3><p>Don't use <code>gin.Context</code> when pass context from handler layer to service layer, use <code>gin.Context.Request.Context()</code> instead.<h3>If you want log, just use <ahref=https://github.com/uber-go/zap>uber-go/zap</a></h3><p>It is fast!<ul><li><p>Don't overuse <code>func (*Logger) With</code>. Because if log line is too long, there is a possibility that we can lost it.<li><p>Use <code>MarshalLogObject</code> when we need to hide some field of object when log (field has long or sensitive value)<li><p>Don't use <code>Panic</code>. Use <code>Fatal</code> for errors when start service to check dependencies. If you really need panic level, use <code>DPanic</code>.<li><p>Use <code>contextID</code> or <code>traceID</code> in every log lines for easily debug.</ul><h3>Don't overuse ORM libs, no need to handle another layer above SQL.</h3><p>Each ORM libs has each different syntax.<br>To learn and use those libs correctly is time consuming.<br>So just stick to plain SQL.<br>It is easier to debug when something is wrong.<p>But <code>database/sql</code> has its own limit.<br>For example, it is hard to get primary key after insert/update.<br>So may be you want to use ORM for those cases.<h3>If you want test, just use <ahref=https://github.com/stretch
