How Golang implements scripts in development

Golang is a programming language that has attracted much attention in recent years. Its fast compilation speed, good concurrency, and ease of development and maintenance have been widely used in many practical application scenarios. Of course, Golang also supports the characteristics of scripting languages. This article mainly introduces how Golang implements script functions in development.

The characteristic of scripting language is that it is interpreted and executed at runtime rather than compiled into executable code in advance. This means that scripting language can dynamically generate logic and has higher flexibility and scalability. For application software with high requirements for rapid iteration functions and dynamics, especially Web applications, scripting language can be written in a more efficient way.
Golang has supported compilation into executable files in its early days, but since version 1.5, the official has improved Golang's support for scripting languages ​​to a higher level and implemented the "go run" command, which supports the command to run source files. This is because golang code cannot be executed directly on the computer. go run actually compiles the code first and then executes the code immediately, so that the golang source file can be run directly.

However, Golang is not actually a native scripting language. It does not support eval and other dynamic-related functions. Therefore, how to implement script functions in Golang? The following will be divided into two aspects and introduced separately.

1. Hybrid programming using shell Golang

A simple way to implement scripts in Golang is by mixing shell and Golang programming. This method can complete script tasks by calling shell commands in Golang. You can use the os/exec package, which provides a high-level API for calling system commands. Through the os/exec package, we can execute shell commands, pass parameters and use that information in scripts.

The following is a sample code:

package main

import (
    "fmt"
    "os/exec"
)

func main() {
    out, err := exec.Command("echo", "hello", "world").Output()
    if err != nil {
        fmt.Println(err)
        return
    }
    fmt.Printf("%s", out)
}

The above code passes in the two parameters hello and world by executing the echo command, and the output result is "hello world". When calling external commands, you need to pay attention to the following points:

1. exec.Command() requires at least two parameters to be passed in. The first parameter is the command name, and the second parameter is the command parameter
2. After executing this command, two values ​​will be returned. The first is the output result during the execution, and the second is any errors that occur during the execution.

By mixing the shell and Golang, we can achieve a more flexible script execution method in Golang while still maintaining the maintainability and scalability of Golang.

2. Use Golang’s plug-in mechanism

In addition to using the shell mixing method, Golang also provides a plug-in mechanism. Using the plug-in mechanism, we can package the code into a dynamic library that can be loaded and run, and loaded when the program is running. The benefit of this approach is the ability to dynamically load and unload code, resulting in greater flexibility and scalability.

The following is a sample code:

package main

import (
    "plugin"
    "github.com/qfg040304/goplugin/hello"
)

func main() {
    p, err := plugin.Open("plugin.so")
    if err != nil {
        panic(err)
    }
    i, err := p.Lookup("Hello")
    if err != nil {
        panic(err)
    }
    f := i.(func())
    f()
    hello.World()
}

In the above code, we first use the plugin package to open the dynamic library named "plugin.so", and then use the Lookup function to obtain the file named " Hello" symbol. Here, symbol is what we defined before. It will be the function to be exported in the dynamic library, and the plug-in mechanism will bind it to the library. After executing the function, we call the external package "hello" and execute the "World()" function in it.

The plug-in mechanism provides Golang with a highly flexible way to dynamically load and unload code as needed while the program is running. Since it supports all features of Go, this method is also very safe and reliable.

Summary

Although Golang itself is not a native scripting language, by mixing shell and Golang programming and using Golang's plug-in mechanism, we can implement script functions in Golang. Through flexible programming methods and powerful Go language features, we can use Golang in a wider range of application scenarios.

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