Golang の Web フレームワーク Echo フレームワークを使用した分散タスク スケジューリングの実装

go get -u github.com/labstack/echo/v4

package main

import (
    "github.com/labstack/echo/v4"
    "net/http"
)

type Task struct {
    Id      int
    Command string
}

var tasks []Task

func AddTask(c echo.Context) error {
    var task Task
    c.Bind(&task)
    task.Id = len(tasks) + 1
    tasks = append(tasks, task)
    return c.JSON(http.StatusOK, task)
}

func DeleteTask(c echo.Context) error {
    id := c.Param("id")
    for i, task := range tasks {
        if strconv.Itoa(task.Id) == id {
            tasks = append(tasks[:i], tasks[i+1:]...)
            return c.String(http.StatusOK, "Task has been deleted")
        }
    }
    return c.String(http.StatusNotFound, "Task not found")
}

func ListTasks(c echo.Context) error {
    return c.JSON(http.StatusOK, tasks)
}

func RunTask(c echo.Context) error {
    id := c.Param("id")
    for _, task := range tasks {
        if strconv.Itoa(task.Id) == id {
            exec.Command(task.Command).Start()
            return c.String(http.StatusOK, "Task has been started")
        }
    }
    return c.String(http.StatusNotFound, "Task not found")
}

func main() {
    e := echo.New()
    e.POST("/tasks", AddTask)
    e.DELETE("/tasks/:id", DeleteTask)
    e.GET("/tasks", ListTasks)
    e.POST("/tasks/:id/run", RunTask)
    e.Logger.Fatal(e.Start(":8080"))
}

go run main.go

package main

import (
    "fmt"
    "github.com/labstack/echo/v4"
    "net/http"
    "strconv"
    "time"
)

type TaskResult struct {
    Id        int
    StartTime time.Time
    EndTime   time.Time
    Result    string
}

var taskResults []TaskResult

func AddWorker(c echo.Context) error {
    return c.String(http.StatusOK, "Worker registered")
}

func ReceiveTask(c echo.Context) error {
    id := c.Param("id")
    for _, task := range tasks {
        if strconv.Itoa(task.Id) == id {
            taskResult := TaskResult{
                Id:        task.Id,
                StartTime: time.Now(),
            }
            //Execute task here
            taskResult.Result = "Task finished"
            taskResult.EndTime = time.Now()
            taskResults = append(taskResults, taskResult)
            return c.String(http.StatusOK, "Task has been finished")
        }
    }
    return c.String(http.StatusNotFound, "Task not found")
}

func ReportTaskResult(c echo.Context) error {
    var taskResult TaskResult
    c.Bind(&taskResult)
    for i, tr := range taskResults {
        if tr.Id == taskResult.Id {
            taskResults[i] = taskResult
            return c.String(http.StatusOK, "Task result has been reported")
        }
    }
    return c.String(http.StatusNotFound, "Task result not found")
}

func main() {
    e := echo.New()
    e.POST("/workers", AddWorker)
    e.POST("/tasks/:id", ReceiveTask)
    e.POST("/results", ReportTaskResult)
    e.Logger.Fatal(e.Start(":8081"))
}

go run worker.go