Golang调试功能

Question

Coming from shell programming, where i used a lot such function:

log_action() {
case "${1}" in
'ERROR')
    EXIT_CODE="${3}"
    echo "[${1}] | $(date +"%T") | ${2} | Exiting (${EXIT_CODE})"
    exit ${EXIT_CODE};
;;
'WARNING')
    echo "[${1}] | $(date +"%T") | ${2} | Line: (${3})"
;;
'DEBUG')
    if [[ ${DEBUG} -eq "1" ]]; then {
    echo "[${1}] | $(date +"%T") | ${2} | ${3}"
    }; fi
;;
*)
    echo "[${1}] | $(date +"%T") | ${2} | ${3}"
;;
esac
}


log_action "WARNING" "Cannot Connect to MySQL Database" "${LINENO}")

Now, i started to learn golang and will like to convert all bash scripts to go. So, I need the same function to use in golang, i tried the following:

func logHandler(t string, e string, l string) {
    switch t {
    case "warning":
        fmt.Println("WARNING")
    case "error":
        fmt.Println("ERROR")
    case "debug":
        fmt.Println("DEBUG |", e, l)
    }
}

logHandler("debug", "Test Function", "LineNumber")

but i don't know how to get the current linenumber variable (LineNumber) when calling logHandler function and pass it to the function as string or as int.

Also, is there any way to run a go script in trace mode like in bash option: set -o xtrace?

I'm just a beginner so if i'm doing something wrong please point me to the right direction. Thank You.

Answer 1

Here's one elegant way you can do it.

We'll be using the runtime package, here's how:

package main

import (
    "fmt"
    "runtime"
)

func main() {
    logHandler("warning", "Test Function")
    logHandler("error", "Test Function")
    logHandler("debug", "Test Function")
}

func logHandler(t, e string) {
    switch t {
    case "warning":
        fmt.Println("WARNING |", e)
    case "error":
        fmt.Println("ERROR   |", e)
    case "debug":
        // 0 = This function
        // 1 = Function that called this function
        _, fn, line, _ := runtime.Caller(1)
        fmt.Printf("DEBUG   | %s:%d | %v
", fn, line, e)
    }
}

Outputs:

WARNING | Test Function
ERROR   | Test Function
DEBUG   | /home/runner/main.go:11 | Test Function

Working example link

---

You could basically do this for all of them (warning and debug)

If you're interested here's some additional reading regarding the runtime package.

---

Inspired by this great answer from OneOfOne.