🚀 Consistent way of logging and fix middleware log format

[kousikmitra]

Description

• Replace all fmt.Print* with log.Print*
• Use [MIDDLEWARENAME] - [LOG-LEVEL] text in all middleware for logging

Fixes #2402

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• For new functionalities I follow the inspiration of the express js framework and built them similar in usage
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation - /docs/ directory for https://docs.gofiber.io/
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• If new dependencies exist, I have checked that they are really necessary and agreed with the maintainers/community (we want to have as few dependencies as possible)
• I tried to make my code as fast as possible with as few allocations as possible
• For new code I have written benchmarks so that they can be analyzed and improved

Commit formatting:

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[welcome]

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[efectn]

We should add interface like https://github.com/labstack/echo/blob/master/log.go#L11 to make it customizable (maybe smaller). For example i may want to use zerolog, zap with fiber

[kousikmitra]

We should add interface like https://github.com/labstack/echo/blob/master/log.go#L11 to make it customizable (maybe smaller). For example i may want to use zerolog, zap with fiber

That would be a good addition. I can work on it. But I think a separate PR would be better instead of adding here.

[efectn]

We should add interface like https://github.com/labstack/echo/blob/master/log.go#L11 to make it customizable (maybe smaller). For example i may want to use zerolog, zap with fiber

That would be a good addition. I can work on it. But I think a separate PR would be better instead of adding here.

Ok to me

[leonklingele]

I'd prefer [LEVEL] [SCOPE, e.g. MIDDLEWARE_NAME] [MESSAGE] [DETAILS] over having [SCOPE] [LEVEL] ...

Why don't we use a proper logging library like zerolog or zap though?

[efectn]

I'd prefer [LEVEL] [SCOPE, e.g. MIDDLEWARE_NAME] [MESSAGE] [DETAILS] over having [SCOPE] [LEVEL] ...

Why don't we use a proper logging library like zerolog or zap though?

We shouldn't add extra dependencies for optional things

[kousikmitra]

Totally agree with @efectn , I have opened an issue to track this. Please feel free to add additional context.

[gaby]

I agree with @leonklingele it should be [LEVEL] [MIDDLEWARE_NAME] [MESSAGE]. It looks weird to have the level after the middleware name

[leonklingele]

ftr: this‘ll soon be part of the Go stdlib 🫨🥳🚀 https://pkg.go.dev/golang.org/x/exp/slog

[efectn]

ftr: this‘ll soon be part of the Go stdlib 🫨🥳🚀

https://pkg.go.dev/golang.org/x/exp/slog

Seems slower than zerolog and zap. At least for now https://github.com/uber-go/zap#performance

[kousikmitra]

I agree with @leonklingele it should be [LEVEL] [MIDDLEWARE_NAME] [MESSAGE]. It looks weird to have the level after the middleware name

Ya agree, if others agree I will make the change here.

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[leonklingele]

Why did this get merged already? Didn’t we want to change the order of log level and scope info?

[ReneWerner87]

Missed it, will revert it

next time it is better to store a task in the pull request or to reject it first, then I usually check it first
but without this it is quite hard for me to keep track of the 10 repositories with all the communication in the pull requests and issues

[leonklingele]

I‘d leave it as-is and just do a fixup.

[ReneWerner87]

#2444

[ReneWerner87]

We should add interface like https://github.com/labstack/echo/blob/master/log.go#L11 to make it customizable (maybe smaller). For example i may want to use zerolog, zap with fiber

what do you think about this kind of solution

package main

import (
	"fmt"
	"log"
)

type Logger struct {
	topic string
}

func NewLogger(topic string) *Logger {
	return &Logger{topic: topic}
}

func (l *Logger) formatMessage(level, format string, args ...interface{}) string {
	message := fmt.Sprintf(format, args...)
	if l.topic != "" {
		return fmt.Sprintf("[%s] - [%s] %s", level, l.topic, message)
	}
	return fmt.Sprintf("[%s] - %s", level, message)
}

func (l *Logger) Info(format string, args ...interface{}) {
	log.Println(l.formatMessage("Info", format, args...))
}

func (l *Logger) Warning(format string, args ...interface{}) {
	log.Println(l.formatMessage("Warning", format, args...))
}

func (l *Logger) Error(format string, args ...interface{}) {
	log.Println(l.formatMessage("Error", format, args...))
}

func main() {
	cacheLogger := NewLogger("CACHE")
	cacheLogger.Warning("Key is deprecated, please use KeyGenerator")

	corsLogger := NewLogger("CORS")
	corsLogger.Warning("Both 'AllowOrigins' and 'AllowOriginsFunc' have been defined.")

	csrfLogger := NewLogger("CSRF")
	csrfLogger.Warning("TokenLookup is deprecated, please use KeyLookup")

	idempotencyLogger := NewLogger("IDEMPOTENCY")
	key := "example_key"
	err := fmt.Errorf("an error occurred")
	idempotencyLogger.Error("failed to unlock key %q: %v", key, err)

	generalLogger := NewLogger("")
	generalLogger.Warning("Parse() is deprecated, please use Load() instead.")
}

or we use the slog lib
https://pkg.go.dev/golang.org/x/exp/slog
the idea was from @leonklingele