在golang中捕获ping命令的结果

Question

I have result of ping command in two ways->

1->5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.067/0.078/0.087/0.007 ms

2->5 packets transmitted, 5 received, 0% packet loss, time 801ms
rtt min/avg/max/stddev = 0.019/0.034/0.044/0.010 ms, ipg/ewma 200.318/0.038 ms

these are results of ping command in two different platforms. Now From this I want value of avg/stddev in both the cases. I have written a regex-

var latencyPattern = regexp.MustCompile("(round-trip|rtt) .* = (.*)/(.*)/(.*)/(.*) *ms,")
if matches := latencyPattern.FindStringSubmatch(strOutput); len(matches) >= 5{
    latency, _ = strconv.ParseFloat(strings.TrimSpace(matches[3]), 64)
    jitter, _ = strconv.ParseFloat(strings.TrimSpace(matches[5]), 64)
}

Now this pattern is working fine for 2nd result of ping (giving me 0.034 and 0.01 as result). But for result 1, it is not able to find the pattern (i.e. to give 0.078 and 0.007). How can I change the regex to work for both?

Answer 1

You need to be more precise when defining the regex. .* is too greedy and matches across commas and other stuff.

I suggest using

var latencyPattern = regexp.MustCompile(`(round-trip|rtt)\s+\S+\s*=\s*([0-9.]+)/([0-9.]+)/([0-9.]+)/([0-9.]+)\s*ms`)

See the regex demo.

Go lang demo:

package main

import (
    "fmt"
    "regexp"
    "strings"
    "strconv"
)

func main() {
    strOutput := `1->5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.067/0.078/0.087/0.007 ms 
        2->5 packets transmitted, 5 received, 0% packet loss, time 801ms
rtt min/avg/max/stddev = 0.019/0.034/0.044/0.010 ms, ipg/ewma 200.318/0.038 ms`
    latencyPattern := regexp.MustCompile(`(round-trip|rtt)\s+\S+\s*=\s*([0-9.]+)/([0-9.]+)/([0-9.]+)/([0-9.]+)\s*ms`)
    matches := latencyPattern.FindAllStringSubmatch(strOutput, -1)
    for _, item := range matches {
        latency, _ := strconv.ParseFloat(strings.TrimSpace(item[3]), 64)
            jitter, _ := strconv.ParseFloat(strings.TrimSpace(item[5]), 64)
            fmt.Printf("AVG = %.3f, STDDEV = %.3f
", latency, jitter)

        }
}

Result:

AVG = 0.078, STDDEV = 0.007
AVG = 0.034, STDDEV = 0.010

Pattern details:

• (round-trip|rtt) - round-trip or rtt substrings
• \s+ - 1+ whitespaces
• \S+ - 1+ non-whitespace symbols
• \s*=\s* - a = enclosed with 0+ whitespaces
• ([0-9.]+) - Group 1: the first number
• / - a /
• ([0-9.]+) - Group 2: the second number
• / - a /
• ([0-9.]+) - Group 3: the third number
• / - a /
• ([0-9.]+) - Group 4: the fourth number
• \s* - 0+ whitespaces
• ms - a substring ms