Avoid logging potentially sensitive data

[davidje13]

I have a use-case where semi-sensitive data is passed around through a redis queue. This data should not be revealed in the logs, but https://github.com/RichardKnop/machinery/blob/master/v1/brokers/redis.go#L211 causes the data to appear.

Ideally it should be possible to suppress this output without suppressing all log output (currently it is possible to provide an alternative logger implementation but since the log line doesn't set any log level such as Debug, it can't be selectively filtered)

Using a custom broker seems to be the only possibility, but this is awkward since it requires copying the code of brokers/redis.go and factories.go to create an alternative redis implementation (an issue which seems to be related to #97).

Could a flag be added to denote data as sensitive, and therefore not to be logged anywhere? Alternatively, could that log line be changed to debug level (or other log lines be changed to warn level as appropriate) so that this could be filtered by the logger?

[RichardKnop]

@davidje13 If you would like to contribute, this sounds like a useful feature. PR welcome!

I might add this functionality to filter out certain logs (perhaps based on level) in the future but not sure how soon it will be as there are other issues higher on my list of things I want to do first.

So if you need this quickly, I'm open to merging a PR that solves this.

[RichardKnop]

@davidje13 You can use your custom logger to filter out certain logs: https://github.com/RichardKnop/machinery#custom-logger