Channel: Logging output

[oxzi]

Currently the channels are not able to log anything, which makes debugging unnecessarily difficult¹.

Due to the strict request-response API logic, a new "Log" method should be introduced, which just got consumed from the RPC,
wrapping the message and logging it to icinga-notification's logger. On the channel's side, a specially configured zap logger is needed.

Footnotes

1. I just stumbled about Channel Form: Unexpected default value behavior as placeholder icinga-notifications-web#154 again, even as I filled this issue back then.. ↩

[julianbrost]

Currently the channels are not able to log anything

Their stderr should be forwarded to the daemon logs:

icinga-notifications/internal/channel/plugin.go

Lines 70 to 76 in cef9ec2

	logRead, logWrite, err := os.Pipe()
	if err != nil {
	return nil, fmt.Errorf("failed to create logRead/logWrite pipe: %w", err)
	}
	cmd.Stderr = logWrite
	childIOPipes = append(childIOPipes, logWrite)
	parentIOPipes = append(parentIOPipes, logRead)

icinga-notifications/internal/channel/plugin.go

Line 90 in cef9ec2

go forwardLogs(logRead, l)

icinga-notifications/internal/channel/plugin.go

Lines 157 to 166 in cef9ec2

	func forwardLogs(errPipe io.Reader, logger *zap.SugaredLogger) {
	scanner := bufio.NewScanner(errPipe)
	for scanner.Scan() {
	logger.Info(scanner.Text())
	}
	if err := scanner.Err(); err != nil {
	logger.Errorw("Failed to scan stderr line", zap.Error(err))
	}
	}

While not perfect (in particular, this doesn't allow to convey the severity of a message at the moment), this should be enough for debugging purposes.

[oxzi]

Thanks, I wasn't aware of this as I mostly looked into pkg/plugin and only briefly into internal/channel. Then I would suggest documenting the stderr behavior somewhere in pkg/plugin and furthermore initialize a custom zap logger in RunPlugin to allow writing same logging code as everywhere else.