log (archived)

This repository is archived and unmaintained. It is kept for history only.

A levelled logger for uniqush-push, written in 2011 and last changed in 2018. uniqush-push was its only real user, and it now has this code in-tree at log: same Logger interface, one bug fixed.

Use the copy in uniqush-push

import "github.com/uniqush/uniqush-push/log"

logger := log.NewLogger(os.Stderr, "[uniqush] ", log.LevelInfo)

Differences from the code here:

• Fatal and Fatalf format their arguments. See below.
• The level constants follow Go's naming convention: LOGLEVEL_INFO is LevelInfo. Their values are written out rather than derived from iota after a negative constant, which had made LOGLEVEL_FATAL 1 and left an unused slot at index 0 of the level table.
• MultiLogger is gone. It had no users, and Fatal through it only ever reached the first logger anyway, because the standard library's Fatal exits.
• There are tests.

The bug, if you have vendored this

nullLoggerWrapper — the discarding logger used for every level above the configured one — forwarded its arguments to the standard library as a single slice instead of expanding them:

func (l *nullLoggerWrapper) Fatalf(format string, v ...interface{}) {
	l.inner.Fatalf(format, v)     // wants v...
}

func (l *nullLoggerWrapper) Fatal(v ...interface{}) {
	l.inner.Fatal(v)              // wants v...
}

So this:

log.NewLogger(os.Stderr, "", log.LOGLEVEL_SILENT).
	Fatalf("cannot start: %v on port %d", "bind failed", 8080)

prints:

[Fatal] 2026/09/08 18:03:37 cannot start: [bind failed 8080] on port %!d(MISSING)

Only the fatal methods are affected, because they are the only ones the discarding logger passes through — the point of that type is that a disabled Debugf never reaches Sprintf, while a fatal still prints even when logging is switched off.

Which is what makes it worth a section of its own. The bug is confined to the case where the operator has silenced logging, and in that case the fatal line is the only output they get when the process dies. In uniqush that meant log=off in uniqush.conf.

go vet reports it:

log.go:96:2: missing ... in args forwarded to print-like function
log.go:100:2: missing ... in args forwarded to printf-like function

It went unreported for nine years because this repository had no CI, no go.mod, and one user. That is why the code moved rather than being fixed here: fixing it here would have meant first giving the repository a module and a release, to serve nobody but uniqush.

The fix is v... in both methods.

License: Apache-2.0