Repository: uber-go/zap
File: options.go (Go)

Code before:
// Copyright (c) 2016 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package zap

// Option is used to set options for the logger.
type Option interface {
	apply(*logger)
}

// optionFunc wraps a func so it satisfies the Option interface.
type optionFunc func(*logger)

func (f optionFunc) apply(log *logger) {
	f(log)
}

// Fields sets the initial fields for the logger.
func Fields(fs ...Field) Option {
	return optionFunc(func(l *logger) {
		l.fac = l.fac.With(fs)
	})
}

// ErrorOutput sets the destination for errors generated by the logger. The
// supplied WriteSyncer is automatically wrapped with a mutex, so it need not be
// safe for concurrent use.
func ErrorOutput(w WriteSyncer) Option {
	return optionFunc(func(log *logger) {
		log.errorOutput = newLockedWriteSyncer(w)
	})
}

// Development puts the logger in development mode, which alters the behavior
// of the DPanic method.
func Development() Option {
	return optionFunc(func(log *logger) {
		log.development = true
	})
}

// AddCaller configures the Logger to annotate each message with the filename
// and line number of zap's caller.
func AddCaller() Option {
	return AddCallerSkip(0)
}

// AddCallerSkip configures the Logger to annotate each message with the filename
// and line number of a caller outside of zap; which caller in the stack is
// controlled by the skip argument. If more than one AddCallerSkip option is
// provided, then the maximum skip amount is used.
func AddCallerSkip(skip int) Option {
	return optionFunc(func(log *logger) {
		log.addCaller = true
		if n := skip + _defaultCallerSkip; n > log.callerSkip {
			log.callerSkip = n
		}
	})
}

// AddStacks configures the Logger to record a stack trace for all messages at
// or above a given level. Keep in mind that this is (relatively speaking)
// quite expensive.
//
// TODO: why is this called AddStacks rather than just AddStack or
// AddStacktrace?
func AddStacks(lvl Level) Option {
	return optionFunc(func(log *logger) {
		log.addStack = lvl
	})
}


Review comment (security):
I think of these as orthogonal options: `AddCaller` is for users to indicate that they'd like to include caller names, and `AddCallerSkip` is for extension authors to make sure that the logged caller is accurate. I imagine wrapper authors, including the proposed sugared logger, taking a slice of options from the user and adding on `AddCallerSkip(n)` (to account for the frames occupied by their wrapper) before passing the result on to the inner logger constructor (which might itself be a wrapper).

Given that, I think that this option should just do `log.callerSkip += skip`.

Code after:
// Copyright (c) 2016 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package zap

// Option is used to set options for the logger.
type Option interface {
	apply(*logger)
}

// optionFunc wraps a func so it satisfies the Option interface.
type optionFunc func(*logger)

func (f optionFunc) apply(log *logger) {
	f(log)
}

// Fields sets the initial fields for the logger.
func Fields(fs ...Field) Option {
	return optionFunc(func(l *logger) {
		l.fac = l.fac.With(fs)
	})
}

// ErrorOutput sets the destination for errors generated by the logger. The
// supplied WriteSyncer is automatically wrapped with a mutex, so it need not be
// safe for concurrent use.
func ErrorOutput(w WriteSyncer) Option {
	return optionFunc(func(log *logger) {
		log.errorOutput = newLockedWriteSyncer(w)
	})
}

// Development puts the logger in development mode, which alters the behavior
// of the DPanic method.
func Development() Option {
	return optionFunc(func(log *logger) {
		log.development = true
	})
}

// AddCaller configures the Logger to annotate each message with the filename
// and line number of zap's caller.
func AddCaller() Option {
	return optionFunc(func(log *logger) {
		log.addCaller = true
	})
}

// AddCallerSkip increases the number of callers skipped by caller annotation
// (as enabled by the AddCaller option).
func AddCallerSkip(skip int) Option {
	return optionFunc(func(log *logger) {
		log.callerSkip += skip
	})
}

// AddStacks configures the Logger to record a stack trace for all messages at
// or above a given level. Keep in mind that this is (relatively speaking)
// quite expensive.
//
// TODO: why is this called AddStacks rather than just AddStack or
// AddStacktrace?
func AddStacks(lvl Level) Option {
	return optionFunc(func(log *logger) {
		log.addStack = lvl
	})
}