[Golang][kafka]“exec.Command()”在运行kcat/kafkaat时不产生输出,或任何错误状态

我需要包起来 kcat 在Go函数中读取一系列主题消息,因此考虑使用 exec.Command() 原因如下:

package main

import (
    "fmt"
    "os/exec"
)

func main() {

    cmd := exec.Command("kcat", "-b kafka.kafka.svc.cluster.local:9092", "-t messages", "-o 11000", "-c 11333")

    fmt.Println("Command String:", cmd.String())

    out, err := cmd.CombinedOutput()

    if err != nil {
        fmt.Println("Error Accessing kafka topic messages ", err.Error(), string(out))
        return
    }

    fmt.Println("Result Length:", len(out))

    fmt.Println("Result Content:", string(out))

}

但是,这只返回的第一行 kcat 输出:

/app/tools # ./five
Command String: /usr/bin/kcat -b kafka.kafka.svc.cluster.local:9092 -t messages -o 11000 -c 11333
Result Length: 58

Result Content: % Auto-selecting Producer mode (use -P or -C to override)

(注意:我在docker容器中运行这个,但我认为它没有什么区别)

但是,当直接从CLI运行时,此操作效果良好:

/app/tools # 
/app/tools # kcat -b kafka.kafka.svc.cluster.local:9092 -t messages -o 10 -c 15
% Auto-selecting Consumer mode (use -P or -C to override)
%4|1640957136.462|OFFSET|rdkafka#consumer-1| [thrd:main]: messages [1]: offset reset (at offset 10) to END: fetch failed due to requested offset not available on the broker: Broker: Offset out of range
%4|1640957136.483|OFFSET|rdkafka#consumer-1| [thrd:main]: messages [2]: offset reset (at offset 10) to END: fetch failed due to requested offset not available on the broker: Broker: Offset out of range
[{"Name":"newOrder", "ID":"9266","Time":"9266","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"1547","Time":"1547","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"9179","Time":"9179","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"8740","Time":"8740","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"9318","Time":"9318","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"1743","Time":"1743","Data":"new order", "Eventname":"newOrder"}]

似乎有一些独特之处 kcat 中断的命令 执行官。命令() 在Go中。

问题:

• 我在围棋中还有其他方法可以达到同样的效果吗?
• 这可能是我使用方式的问题吗 执行官。命令()

理想情况下,我可以使用 kcat 命令,因为我想避免使用segmentios kafka-go 库。

[编辑]

• 分开论点(如@onecricketer所建议的):

cmd := exec.Command("kcat", "-b", "kafka.kafka.svc.cluster.local:9092", "-t", "messages", "-o", "11000", "-c", "11333")

结果(相同错误):

/app/tools # ./code
Command String: /usr/bin/kcat -b kafka.kafka.svc.cluster.local:9092 -t messages -o 11000 -c 11333
Result Length: 58
Result Content: % Auto-selecting Producer mode (use -P or -C to override)

• 使用BASH作为外壳(由maxm建议):

相同的结果,即仅报告kcat输出的第一行:

/app/tools # ./code
Command String: /bin/bash -c kcat -b kafka.kafka.svc.cluster.local:9092 -t messages -o 11000 -c 11333
Result Length: 58
Result Content: % Auto-selecting Producer mode (use -P or -C to override)

[编辑]

注意:然而,当我使用Python的shell执行机制时,它工作得很好,这让我怀疑Gos的shell处理功能是否有缺陷:

import subprocess

process = subprocess.Popen(["kcat","-b","kafka.kafka.svc.cluster.local:9092","-t","messages","-o","1", "-c", "11"], 
                           stdout=subprocess.PIPE,
                           universal_newlines=True)

while True:
    output = process.stdout.readline()
    print(output.strip())
    # Do something else
    return_code = process.poll()
    if return_code is not None:
        print('RETURN CODE', return_code)
        # Process has finished, read rest of the output 
        for output in process.stdout.readlines():
            print(output.strip())
        break

结果:

/app/tools/python # python3 code.py 
% Auto-selecting Consumer mode (use -P or -C to override)
%4|1641004616.232|OFFSET|rdkafka#consumer-1| [thrd:main]: messages [2]: offset reset (at offset 1) to END: fetch failed due to requested offset not available on the broker: Broker: Offset out of range
%4|1641004616.236|OFFSET|rdkafka#consumer-1| [thrd:main]: messages [1]: offset reset (at offset 1) to END: fetch failed due to requested offset not available on the broker: Broker: Offset out of range
[{"Name":"newOrder", "ID":"4512","Time":"4512","Data":"new order", "Eventname":"newOrder"}]

RETURN CODE 0
[{"Name":"newOrder", "ID":"2388","Time":"2388","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"8707","Time":"8707","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"1643","Time":"1643","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"2421","Time":"2421","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"7520","Time":"7520","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"1258","Time":"1258","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"1457","Time":"1457","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"2907","Time":"2907","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"9266","Time":"9266","Data":"new order", "Eventname":"newOrder"}]

[{"Name":"newOrder", "ID":"1547","Time":"1547","Data":"new order", "Eventname":"newOrder"}]