我需要包装kcat一个 Go 函数来读取一系列主题消息，因此考虑使用exec.Command()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，这仅返回输出的第一行kcat：
/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 容器中运行它，但我认为这没有什么不同）
但是，当直接从 CLI 运行时，这可以正常工作：
/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"}]
在 Gokcat中中断的命令似乎有一些独特之处。exec.Command()
问题：
- 有没有其他方法可以在 Go 中达到相同的效果？
- 这可能是我使用方式的问题吗
exec.Command()
理想情况下，我可以在这种情况下使用该kcat命令，因为我想避免在这种情况下使用 segmentioskafka-go库。
[编辑]
- 分离论点（如@onecricketeer 所建议）：
cmd := exec.Command("kcat", "-b", "kafka.kafka.svc.cluster.local:9092", "-t", "messages", "-o", "11000", "-c", "11333")
结果（同样的错误）：
/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）：
结果相同，即只报告了 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：但是，当我使用 Python 的 shell 执行机制时，它运行良好，这让我想知道 Gos shell 处理功能是否存在缺陷：
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"}]