Logging stack trace of any go routines

Question

I have an application in which the main go routine spawns few more go routines. Is it possible to log the stack trace for any go routine that crashes? Using "defer debug.Stack()" and "recover()" in the main prints the stack trace of main goroutine as expected. Is there any way to print stack trace of the go routines spawned if they panic ?

Answer 1

If a goroutine panics, its stack trace will be shown.

If a goroutine is calling debug.Stack, its (the calling goroutine's) stack trace will be provided.

Run this example to demonstrate both:

package main

import (
    "fmt"
    "runtime/debug"
    "time"
)

func foo() {
    stack := debug.Stack()
    fmt.Println("foo's stack:", string(stack))

    panic("oh noes")
}

func worker() {
    foo()
}

func main() {
    go foo()
    time.Sleep(200 * time.Millisecond)
}

You'll see something like:

foo's stack: goroutine 6 [running]:
runtime/debug.Stack(0x0, 0x0, 0x0)
    /usr/local/go/src/runtime/debug/stack.go:24 +0x9f
main.foo()
    /tmp/gogo.go:10 +0x26
created by main.main
    /tmp/gogo.go:21 +0x35

panic: oh noes

goroutine 6 [running]:
main.foo()
    /tmp/gogo.go:13 +0xe6
created by main.main
    /tmp/gogo.go:21 +0x35
exit status 2

The first stack trace is what foo obtains with debug.Stack. The second is a result of the unrecovered panic crashing the process.

You can call debug.Stack in a recover. See this answer for example: How to get the stacktrace of a panic (and store as a variable)