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高朗昌在调查结果时被吊死了

goroutine go asynchronous

mornindew · 技术社区 · 6 年前

我对歌朗频道还很陌生,但它并不像我想象的那样运作。

wg.Wait() 完成。

不幸的是,当循环通过成龙的结果将挂起。我假设,因为它仍然在等待成龙得到填补,但不是所有的goroutine都会抛出错误。

处理不总是填充的通道循环的最佳方法是什么?我也知道我不必在这里使用CHANs,但我想确保我理解它们。

下面是我的代码。

func createWorkoutPlanForUserPreconditionCheck(planID, userID, transactionID *string) (*sharedstructs.Plan, *sharedstructs.User, *sharedstructs.Profile, error) {
    if planID == nil || userID == nil || transactionID == nil {
        return nil, nil, nil, sharedstructs.InvalidData{Msg: "Cannot pass in Nil Parameters"}
    }

    plan := sharedstructs.Plan{}
    user := sharedstructs.User{}
    profile := sharedstructs.Profile{}
    //myError := sharedstructs.InvalidData{}
    ch := make(chan sharedstructs.InvalidData, 3)

    var wg sync.WaitGroup
    wg.Add(3)
    //Get the Plan from the Plan ID
    go func() {
        defer wg.Done()
        returnedPlan, readError := readPlan(*planID)
        if readError != nil || returnedPlan == nil {
            ch <- sharedstructs.InvalidData{Msg: "Could Not Retreive the User with ID: " + *userID}
        } else {
            plan = *returnedPlan
        }
    }()

    //Get the User
    go func() {
        defer wg.Done()
        returnedUser, getUserError := userdomain.GetUserByID(*userID, *transactionID)
        if getUserError != nil || &returnedUser == nil {
            ch <- sharedstructs.InvalidData{Msg: "Could Not Retreive the User with ID: " + *userID}
        } else {
            user = returnedUser
        }
    }()

    //Get the Profile
    go func() {
        defer wg.Done()
        readProfile, getProfileError := profiledomain.GetProfile(*userID, *transactionID)
        if getProfileError != nil || readProfile == nil {
            ch <- sharedstructs.InvalidData{Msg: "Could Not Retreive the User with ID: " + *userID}
        } else {
            profile = *readProfile
        }
    }()

    wg.Wait()

    ////"Hangs Here" - PUT MY ERROR HANDLING LOGIC HERE
    for err := range ch {
        fmt.Println(err.Error())
    }

    return &plan, &user, &profile, nil
}

1 回复 | 直到 6 年前

mornindew 6 年前

所以,在发布后不久,我就想出了一个解决办法。我的问题有两个方面:

关闭我的频道以便它知道何时停止收听
使用不一致的方法将数据从goroutine获取到调用函数。对于使用chan的错误,但对于自定义结构,我只是设置它。我将chan泛化为接口{},然后在处理时对其进行类型切换,以确定它是什么类型的结构。

^^^解决这些问题使我的代码能够工作,但这里是我的代码最终的结果。。

func createWorkoutPlanForUserPreconditionCheck(planID, userID, transactionID *string) (*sharedstructs.Plan, *sharedstructs.User, *sharedstructs.Profile, error) {
    if planID == nil || userID == nil || transactionID == nil {
        return nil, nil, nil, sharedstructs.InvalidData{Msg: "Cannot pass in Nil Parameters"}
    }

    outputChannel := make(chan interface{}, 3)
    var wg sync.WaitGroup
    wg.Add(3)

    //Get the Plan from the Plan ID
    go func() {
        defer wg.Done()
        returnedPlan, readError := readPlan(*planID)
        if readError != nil || returnedPlan == nil {
            outputChannel <- sharedstructs.InvalidData{Msg: "Could Not Retreive the User with ID: " + *userID}
        } else {
            outputChannel <- *returnedPlan
        }
    }()

    //Get the User
    go func() {
        defer wg.Done()
        returnedUser, getUserError := userdomain.GetUserByID(*userID, *transactionID)
        if getUserError != nil || &returnedUser == nil {
            outputChannel <- sharedstructs.InvalidData{Msg: "Could Not Retreive the User with ID: " + *userID}
        } else {
            outputChannel <- returnedUser
        }
    }()

    //Get the Profile
    go func() {
        defer wg.Done()
        readProfile, getProfileError := profiledomain.GetProfile(*userID, *transactionID)
        if getProfileError != nil || readProfile == nil {
            outputChannel <- sharedstructs.InvalidData{Msg: "Could Not Retreive the User with ID: " + *userID}
        } else {
            outputChannel <- *readProfile
        }
    }()

    wg.Wait()
    close(outputChannel)

    plan := sharedstructs.Plan{}
    user := sharedstructs.User{}
    profile := sharedstructs.Profile{}
    for result := range outputChannel {
        switch result.(type) {
        case sharedstructs.InvalidData:
            return nil, nil, nil, result.(sharedstructs.InvalidData)
        case sharedstructs.Plan:
            plan = result.(sharedstructs.Plan)
        case sharedstructs.User:
            user = result.(sharedstructs.User)
        case sharedstructs.Profile:
            profile = result.(sharedstructs.Profile)
        }
    }

    return &plan, &user, &profile, nil
}