The secret weapon of generate in the go command

The go generate command simplifies repetitive tasks by automatically generating code, files, and artifacts. Its usage is as follows: 1. go generate [-n] importpath... 2. -n: Print the generated code without showing the actual execution 3. importpath: The import path of the package to be generated 4. Use case example: Generate database connection code (pgxgen ), generate gRPC service stub file (protoc --go-grpc).

The secret weapon of generate in go command

If you are tired of performing repetitive tasks manually, then the go generate command is Your lifesaver. This powerful command can help you generate code, files, and other artifacts, saving a lot of time and effort.

Usage

go generate The basic syntax of the command is as follows:

go generate [-n] importpath...

Among them:

• -n : Indicates that only the generated code is printed without actually executing it
• importpath: The import path of the package to be generated

Use case

go generate The command has many practical uses, here are a few examples.

Generate database connection code

If you are using a database library like github.com/jackc/pgx, you can use go generate to generate database connection code. For example:

//go:generate pgxgen -database pgxgen -skip-columns "ID" -skip-package pgxgen

package pgxgen

import "database/sql"
import _ "github.com/jackc/pgx/stdlib" // pgx driver needed for generate
import _ "github.com/jackc/pgx/gen/dbinit"

var DB *sql.DB

Running go generate will generate the db.go file based on your database schema, which contains the *sql.DB# connected to the database. ##.

Generate gRPC service stub file

If you are using the

github.com/golang/protobuf library, you can use go generate To generate gRPC service stub files. For example:

//go:generate protoc --go-grpc ./*.proto

package main

import (
    "context"
    "log"

    pb "github.com/example/mypackage/api/v1"
    "google.golang.org/grpc"
)

func main() {
    // gRPC server address
    addr := "localhost:5000"

    // Connect to gRPC server
    conn, err := grpc.Dial(addr, grpc.WithInsecure())
    if err != nil {
        log.Fatalf("Did not connect: %v", err)
    }
    defer conn.Close()

    client := pb.NewGreeterClient(conn)

    // Call gRPC service
    resp, err := client.SayHello(context.Background(), &pb.HelloRequest{Name: "John"})
    if err != nil {
        log.Fatalf("Could not greet: %v", err)
    }
    log.Printf("Greeting: %s", resp.Message)
}

Running

go generate will generate the pb.go file, which contains the code of the gRPC service stub.

Conclusion

The go generate command is a powerful tool that allows you to automate code generation tasks. You can save a lot of time and effort by taking full advantage of go generate's capabilities.

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