fix: report timeout as error instead of writing message to stderr

[AstroProfundis]

I have observed panics on some specific commands:

panic: send on closed channel

goroutine 2017 [running]:
github.com/appleboy/easyssh-proxy.(*MakeConfig).Stream.func1(0xc0000ca0a0, 0xc00013e090, 0xc000fea168, 0x1, 0x1, 0xc000de4b80, 0xc000de4c00, 0xc000690ea0, 0xc000690f00, 0xc000690f60, ...)
	/home/allen/go/pkg/mod/github.com/appleboy/[email protected]/easyssh.go:340 +0x385
created by github.com/appleboy/easyssh-proxy.(*MakeConfig).Stream
	/home/allen/go/pkg/mod/github.com/appleboy/[email protected]/easyssh.go:297 +0x4a5

That the stderrChan is closed before timeout message is written to it. However, if closing the channel in the upper level goroutine, it's possible that stderrScanner continues to read data after timeout reached, if the channel is closed in timeout case, it still panics.

So use the errChan to report timeout and let stderrChan purely be with the stderr of command output, to avoid writing and closing the channel in two different goroutines.

[codecov-commenter]

Codecov Report

Merging #68 (d52fc63) into master (e954c88) will decrease coverage by 0.07%.
The diff coverage is 100.00%.

❗ Current head d52fc63 differs from pull request most recent head 9910ebd. Consider uploading reports for the commit 9910ebd to get more accurate results

@@            Coverage Diff             @@
##           master      #68      +/-   ##
==========================================
- Coverage   83.55%   83.48%   -0.08%     
==========================================
  Files           1        1              
  Lines         225      224       -1     
==========================================
- Hits          188      187       -1     
  Misses         21       21              
  Partials       16       16              

Impacted Files	Coverage Δ
easyssh.go	83.48% <100.00%> (-0.08%)	⬇️

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[AstroProfundis]

@amyangfei PTAL too, as this was introduced in #66

[gzuidhof]

I may be wrong, but I'm pretty sure the isTimeout variable is wrong and inverted in this library, this is the relevant bit of code. Maybe it's related?

[realcp1018]

easyssh-proxy/easyssh.go

Lines 336 to 342 in 6671f69

	case <-res:
	errChan <- session.Wait()
	doneChan <- true
	case <-timeoutChan:
	errChan <- fmt.Errorf("Run Command Timeout")
	doneChan <- false
	}

Write false to doneChan is enougth when timeout, no need to send error msg to errChan.

[realcp1018]

I may be wrong, but I'm pretty sure the isTimeout variable is wrong and inverted in this library, this is the relevant bit of code. Maybe it's related?

Rename isTimeout to isDone seems better in Run() loop?