初学者 Go 项目 - 在 Go 中创建任务运行程序

我们要建造什么

我们将制作一个像 make 这样的工具，我们可以使用像这样的简单 yaml 文件来运行任务。

tasks:
    build:
        description:  "compile the project"
        command:  "go build main.go"
        dependencies:  [test]
    test:
        description:  "run unit tests"
        command:  "go test -v ./..."

让我们开始吧，首先我们需要概述行动过程。我们已经定义了任务文件架构。我们可以使用 json 代替 yaml，但为了这个项目，我们将使用 yml 文件。

从文件中我们可以看到，我们需要一个结构来存储单个任务，以及一种在继续主任务之前运行依赖任务的方法。让我们从启动我们的项目开始。创建一个新文件夹并运行：

go mod init github.com/vishaaxl/mommy

您可以随意命名您的项目，我将使用“妈妈”的名字。我们还需要安装一些包来处理 yaml 文件 - 基本上将它们转换为地图对象。继续安装以下软件包。

go get gopkg.in/yaml.v3

接下来创建一个新的 main.go 文件并从定义“Task”结构开始。

package main

import (
    "gopkg.in/yaml.v3"
)
// Task defines the structure of a task in the configuration file.
// Each task has a description, a command to run, and a list of dependencies
// (other tasks that need to be completed before this task).
type Task struct {
    Description  string   `yaml:"description"`  // A brief description of the task.
    Command      string   `yaml:"command"`      // The shell command to execute for the task.
    Dependencies []string `yaml:"dependencies"` // List of tasks that need to be completed before this task.
}

这个是非常不言自明的。这将保存每个单独任务的价值。接下来，我们还需要一个结构体来存储任务列表并将 .yaml 文件的内容加载到这个新对象中。

// Config represents the entire configuration file,
// which contains a map of tasks by name.
type Config struct {
    Tasks map[string]Task `yaml:"tasks"` // A map of task names to task details.
}

// loadConfig reads and parses the configuration file (e.g., Makefile.yaml),
// and returns a Config struct containing the tasks and their details.
func loadConfig(filename string) (Config, error) {
    // Read the content of the config file.
    data, err := os.ReadFile(filename)
    if err != nil {
        return Config{}, err
    }

    // Unmarshal the YAML data into a Config struct.
    var config Config
    err = yaml.Unmarshal(data, &config)
    if err != nil {
        return Config{}, err
    }

    return config, nil
}

接下来我们需要创建一个执行单个任务的函数。我们将使用 os/exec 模块在 shell 中运行任务。 在 Golang 中，os/exec 包提供了一种执行 shell 命令和外部程序的方法。

// executeTask recursively executes the specified task and its dependencies.
// It first ensures that all dependencies are executed before running the current task's command.
func executeTask(taskName string, tasks map[string]Task, executed map[string]bool) error {
    // If the task has already been executed, skip it.
    if executed[taskName] {
        return nil
    }

    // Get the task details from the tasks map.
    task, exists := tasks[taskName]
    if !exists {
        return fmt.Errorf("task %s not found", taskName)
    }

    // First, execute all the dependencies of this task.
    for _, dep := range task.Dependencies {
        // Recursively execute each dependency.
        if err := executeTask(dep, tasks, executed); err != nil {
            return err
        }
    }

    // Now that dependencies are executed, run the task's command.
    fmt.Printf("Running task: %s\n", taskName)
    fmt.Printf("Command: %s\n", task.Command)

    // Execute the task's command using the shell (sh -c allows for complex shell commands).
    cmd := exec.Command("sh", "-c", task.Command)
    cmd.Stdout = os.Stdout // Direct standard output to the terminal.
    cmd.Stderr = os.Stderr // Direct error output to the terminal.

    // Run the command and check for any errors.
    if err := cmd.Run(); err != nil {
        return fmt.Errorf("failed to execute command %s: %v", task.Command, err)
    }

    // Mark the task as executed.
    executed[taskName] = true
    return nil
}

现在我们拥有了程序的所有构建块，我们可以在主函数中使用它们来加载配置文件并开始自动化。我们将使用 flag 包来读取命令行标志。

func main() {
    // Define command-line flags
    configFile := flag.String("f", "Mommy.yaml", "Path to the configuration file") // Path to the config file (defaults to Makefile.yaml)
    taskName := flag.String("task", "", "Task to execute")                             // The task to execute (required flag)

    // Parse the flags
    flag.Parse()

    // Check if the task flag is provided
    if *taskName == "" {
        fmt.Println("Error: Please specify a task using -task flag.")
        os.Exit(1) // Exit if no task is provided
    }

    // Load the configuration file
    config, err := loadConfig(*configFile)
    if err != nil {
        fmt.Printf("Failed to load config: %v\n", err)
        os.Exit(1) // Exit if the configuration file can't be loaded
    }

    // Map to track which tasks have been executed already (avoiding re-execution).
    executed := make(map[string]bool)

    // Start executing the specified task (with dependencies)
    if err := executeTask(*taskName, config.Tasks, executed); err != nil {
        fmt.Printf("Error executing task: %v\n", err)
        os.Exit(1) // Exit if task execution fails
    }
}

让我们测试一下整个过程，创建一个新的 Mommy.yaml 并将开头的 yaml 代码粘贴到其中。我们将使用任务运行程序为我们的项目创建二进制文件。运行：

go run main.go -task build

如果一切顺利，您将在文件夹的根目录中看到一个新的 .exe 文件。太好了，我们现在有了一个可以工作的任务运行程序。我们可以在系统的环境变量中添加此 .exe 文件的位置，并使用以下命令从任何地方使用它：

 mommy -task build

完整代码

package main

import (
    "flag"
    "fmt"
    "os"
    "os/exec"
    "gopkg.in/yaml.v3"
)

// Task defines the structure of a task in the configuration file.
// Each task has a description, a command to run, and a list of dependencies
// (other tasks that need to be completed before this task).
type Task struct {
    Description  string   `yaml:"description"`  // A brief description of the task.
    Command      string   `yaml:"command"`      // The shell command to execute for the task.
    Dependencies []string `yaml:"dependencies"` // List of tasks that need to be completed before this task.
}

// Config represents the entire configuration file,
// which contains a map of tasks by name.
type Config struct {
    Tasks map[string]Task `yaml:"tasks"` // A map of task names to task details.
}

// loadConfig reads and parses the configuration file (e.g., Makefile.yaml),
// and returns a Config struct containing the tasks and their details.
func loadConfig(filename string) (Config, error) {
    // Read the content of the config file.
    data, err := os.ReadFile(filename)
    if err != nil {
        return Config{}, err
    }

    // Unmarshal the YAML data into a Config struct.
    var config Config
    err = yaml.Unmarshal(data, &config)
    if err != nil {
        return Config{}, err
    }

    return config, nil
}

// executeTask recursively executes the specified task and its dependencies.
// It first ensures that all dependencies are executed before running the current task's command.
func executeTask(taskName string, tasks map[string]Task, executed map[string]bool) error {
    // If the task has already been executed, skip it.
    if executed[taskName] {
        return nil
    }

    // Get the task details from the tasks map.
    task, exists := tasks[taskName]
    if !exists {
        return fmt.Errorf("task %s not found", taskName)
    }

    // First, execute all the dependencies of this task.
    for _, dep := range task.Dependencies {
        // Recursively execute each dependency.
        if err := executeTask(dep, tasks, executed); err != nil {
            return err
        }
    }

    // Now that dependencies are executed, run the task's command.
    fmt.Printf("Running task: %s\n", taskName)
    fmt.Printf("Command: %s\n", task.Command)

    // Execute the task's command using the shell (sh -c allows for complex shell commands).
    cmd := exec.Command("sh", "-c", task.Command)
    cmd.Stdout = os.Stdout // Direct standard output to the terminal.
    cmd.Stderr = os.Stderr // Direct error output to the terminal.

    // Run the command and check for any errors.
    if err := cmd.Run(); err != nil {
        return fmt.Errorf("failed to execute command %s: %v", task.Command, err)
    }

    // Mark the task as executed.
    executed[taskName] = true
    return nil
}

func main() {
    // Define command-line flags
    configFile := flag.String("f", "Makefile.yaml", "Path to the configuration file") // Path to the config file (defaults to Makefile.yaml)
    taskName := flag.String("task", "", "Task to execute")                             // The task to execute (required flag)

    // Parse the flags
    flag.Parse()

    // Check if the task flag is provided
    if *taskName == "" {
        fmt.Println("Error: Please specify a task using -task flag.")
        os.Exit(1) // Exit if no task is provided
    }

    // Load the configuration file
    config, err := loadConfig(*configFile)
    if err != nil {
        fmt.Printf("Failed to load config: %v\n", err)
        os.Exit(1) // Exit if the configuration file can't be loaded
    }

    // Map to track which tasks have been executed already (avoiding re-execution).
    executed := make(map[string]bool)

    // Start executing the specified task (with dependencies)
    if err := executeTask(*taskName, config.Tasks, executed); err != nil {
        fmt.Printf("Error executing task: %v\n", err)
        os.Exit(1) // Exit if task execution fails
    }
}

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