Chore: switch to go mod compatible fork of forego

[buchdag]

As discussed in #1579, forego isn't maintained anymore and lacks go module support. This project was already using a fork of forego by jwilder, so I decided to fork it again under the nginx-proxy org and merge in go mod support (thanks to @tkw1536) so that it can be used in this project and unblock building the image with golang >= 1.16.

[buchdag]

@tkw1536 well that's back to the drawing board on this one, the forego version built by alpine fails.

[tkw1536]

I have no idea why the tests fail on alpine. The logs seem to imply that the container just crashes, but I can not reproduce this locally.

I have a strong suspicion that the changes could be caused by any of the commits introduced since v0.16.1. I will see when I have the time to investigate in more detail.

[buchdag]

I will see when I have the time to investigate in more detail.

That's appreciated 👍

No pressure / hurry though, I think we should be fine staying on Go < 1.16 for a while.

[tkw1536]

It's been a while, but I finally got around to tracking why this happens.
I'm locally getting the following stacktrace:

fatal error: concurrent map writes
fatal error: concurrent map writes

goroutine 801 [running]:
runtime.throw(0x59c4c6, 0x15)
        /usr/local/go/src/runtime/panic.go:1116 +0x72 fp=0xc000284c40 sp=0xc000284c10 pc=0x4347d2
runtime.mapassign_faststr(0x574400, 0xc00018e570, 0x598c72, 0x4, 0x7)
        /usr/local/go/src/runtime/map_faststr.go:291 +0x3d8 fp=0xc000284ca8 sp=0xc000284c40 pc=0x413538
main.(*Forego).startProcess(0xc0001a6540, 0x1, 0x0, 0xc00019c120, 0x5, 0xc00019c127, 0x5, 0xc00018e570, 0xc00019c130)
        /go/forego/start.go:195 +0x235 fp=0xc000284e40 sp=0xc000284ca8 pc=0x5514b5
main.(*Forego).startProcess.func2(0xc0001a6540, 0xc000057260, 0x1, 0x0, 0xc00019c120, 0x5, 0xc00019c127, 0x5, 0xc00018e570, 0xc00019c130, ...)
        /go/forego/start.go:239 +0x1a5 fp=0xc000284f78 sp=0xc000284e40 pc=0x552a85
runtime.goexit()
        /usr/local/go/src/runtime/asm_amd64.s:1374 +0x1 fp=0xc000284f80 sp=0xc000284f78 pc=0x468aa1
created by main.(*Forego).startProcess
        /go/forego/start.go:233 +0x885

goroutine 1 [chan receive]:
main.runStart(0x6a81c0, 0xc0000101a0, 0x0, 0x0)
        /go/forego/start.go:329 +0x518
main.main()
        /go/forego/main.go:33 +0x26b

goroutine 17 [chan receive]:
main.(*Forego).monitorInterrupt(0xc0001a6540)
        /go/forego/start.go:157 +0x125
created by main.runStart
        /go/forego/start.go:284 +0x1a7

goroutine 7 [syscall]:
os/signal.signal_recv(0x0)
        /usr/local/go/src/runtime/sigqueue.go:147 +0x9d
os/signal.loop()
        /usr/local/go/src/os/signal/signal_unix.go:23 +0x25
created by os/signal.Notify.func1.1
        /usr/local/go/src/os/signal/signal.go:150 +0x45

goroutine 783 [running]:
        goroutine running on other thread; stack unavailable
created by main.(*Forego).startProcess
        /go/forego/start.go:233 +0x885

goroutine 783 [running]:
runtime.throw(0x59c4c6, 0x15)
        /usr/local/go/src/runtime/panic.go:1116 +0x72 fp=0xc000060c40 sp=0xc000060c10 pc=0x4347d2
runtime.mapassign_faststr(0x574400, 0xc00018e570, 0x598c72, 0x4, 0xb)
        /usr/local/go/src/runtime/map_faststr.go:291 +0x3d8 fp=0xc000060ca8 sp=0xc000060c40 pc=0x413538
main.(*Forego).startProcess(0xc0001a6540, 0x0, 0x0, 0xc0001b8000, 0x9, 0xc0001b800b, 0x5a, 0xc00018e570, 0xc00019c130)
        /go/forego/start.go:195 +0x235 fp=0xc000060e40 sp=0xc000060ca8 pc=0x5514b5
main.(*Forego).startProcess.func2(0xc0001a6540, 0xc0001cd500, 0x0, 0x0, 0xc0001b8000, 0x9, 0xc0001b800b, 0x5a, 0xc00018e570, 0xc00019c130, ...)
        /go/forego/start.go:239 +0x1a5 fp=0xc000060f78 sp=0xc000060e40 pc=0x552a85
runtime.goexit()
        /usr/local/go/src/runtime/asm_amd64.s:1374 +0x1 fp=0xc000060f80 sp=0xc000060f78 pc=0x468aa1
created by main.(*Forego).startProcess
        /go/forego/start.go:233 +0x885

But I don't know why this happens only on Alpine and not on Debian.

[tkw1536]

Ok, I've figured out what the problem is, the default shell under alpine does not seem to support all the features introduced in ddollar/forego@51d9f6d.

[tkw1536]

Going to do some minor cleanup on forego, and then make a PR.

[buchdag]

Excellent news, thanks @tkw1536 ! 👍

[tkw1536]

See nginx-proxy/forego#2, we'll need to update this PR as well.

[buchdag]

Do you recommend using -ldflags "-X main.osShell=sh" or -ldflags "-X main.osShell=ash" for Alpine ?

[buchdag]

Well, both main.osShell=sh and main.osShell=ash stall the tests 😐