Timeouts with Docker TTY

[caarlos0]

Not sure if it is intended or not, but if you run a docker container with --tty, many queries termenv does timeout.

Minimum reproducible:

// main.go
package main

import (
	"fmt"

	"github.com/muesli/termenv"
)

func main() {
	fmt.Println("BG", termenv.BackgroundColor())
}

GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o a .
docker run --rm --tty -v $PWD:/tmp alpine /tmp/a

[johnstcn]

I amended @caarlos0 's example above to write tracing output:

// main.go
package main

import (
	"fmt"
	"os"
	"runtime/trace"

	"github.com/muesli/termenv"
)

func main() {
	f, err := os.OpenFile("/tmp/trace.out", os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0755)
	if err != nil {
		panic(err)
	}
	defer f.Close()
	trace.Start(f)
	defer trace.Stop()
	fmt.Println("BG", termenv.BackgroundColor())
}
// go.mod
module termenvtimeout

go 1.20

require github.com/muesli/termenv v0.15.1

require (
	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
	github.com/mattn/go-isatty v0.0.17 // indirect
	github.com/mattn/go-runewidth v0.0.14 // indirect
	github.com/rivo/uniseg v0.2.0 // indirect
	golang.org/x/sys v0.6.0 // indirect
)

Running with Docker (in this case, Colima v0.5.5 aarch64) shows the following:

$ GOOS=linux GOARCH=arm64 CGO_ENABLED=0 go build -o a .
$ docker run --rm --tty -v $PWD:/tmp alpine time /tmp/a
^[]11;rgb:14a7/195f/1efb^G^[[116;1RBG #000000
real	0m 5.03s
user	0m 0.00s
sys	0m 0.00s

I'm attaching the resulting trace, but here's the syscall graph for reference:

It looks like the culprit is https://github.com/muesli/termenv/blob/master/termenv_unix.go#L142