[
https://issues.apache.org/jira/browse/THRIFT-4985?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16958234#comment-16958234
]
Yuxuan Wang commented on THRIFT-4985:
-------------------------------------
The causer example is different from this one. In that example it's optional.
If the error doesn't really implement it, it still works as expected. Here the
closest thing we can do is if the logger passed in doesn't implement the
unexported interface, we fallback to use the default logger. Is that "work as
expected"? I'd say that's very debatable.
Also if we have this function:
{code:go}
func SetLogger(l logger) {
log = l
}
{code}
We are actually making an exported function (which is part of our API)
depending on an unexported interface (which the intention was to make it not
part of our API). If we change the interface of logger in the future, the code
still breaks so we didn't achieve the intention of "not making it part of our
API". We can bypass that by make it interface{} instead, but that falls back to
the above point.
> Clean up logging in go library
> ------------------------------
>
> Key: THRIFT-4985
> URL: https://issues.apache.org/jira/browse/THRIFT-4985
> Project: Thrift
> Issue Type: Improvement
> Components: Go - Library
> Reporter: Yuxuan Wang
> Priority: Major
>
> As principals:
> # As a library, the library itself shouldn't do any logging. It should
> always return the error to the caller (library user), and let them to decide
> how to handle them (logging, panic, etc.)
> # In some cases it's not possible to return the error to the caller, so some
> logging is necessary, but those should be kept minimal, and made more
> controllable to the caller.
> Looking at how we do logging in go library now:
> # We have logging inside
> [TZlibTransport|https://github.com/apache/thrift/blob/6e4c581fddae9106c2c5a59c4d0bfbe6ad3e4560/lib/go/thrift/zlib_transport.go#L70],
> which fits Principal 1 above and should be removed
> # We have logging inside TSimpleServer, which fits Principal 2 above (those
> are in the accept loop so there's no easy way to return the errors to the
> caller)
> For Principal 2, one of the problem is that we can't just force all the
> callers to use the same logging library. There are a lot of logging libraries
> and it's not always possible to convert them into each other. Some people
> might be using [go-kit logger|https://godoc.org/github.com/go-kit/kit/log]
> because they want structured logging, or because they are already using
> go-kit for other things, and some people might be using
> [zap|https://godoc.org/go.uber.org/zap] for its performance. They are both
> incompatible to the stdlib log library.
> This, combined with the part that we should keep the logging minimal, is why
> I propose a simple, common ground that's easy to wrap any logging library
> into:
> {code:go}
> type Logger func(msg string)
> {code}
> Whatever logging library the user is already using, it's easy to write a
> lambda to convert that to this common ground, for example for the stdlib log
> library:
> {code:go}
> func StdLogger(logger *log.Logger) Logger {
> return func(msg string) {
> logger.Print(msg)
> }
> }
> {code}
> You can even have one to be used in tests, because the purpose of logging is
> that it's only used for situations that is bad, we can make it that whenever
> the logging is called we should fail the test:
> {code:go}
> func TestLogger(tb testing.TB) Logger {
> return func(msg string) {
> tb.Errorf("logger called with msg: %q", msg)
> }
> }
> {code}
> This way, the caller can make sure that the logging from inside the thrift
> library is using the same logger as what they are already using, or they can
> suppress the logging entirely if they choose to.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
