✨ Add customTags in logger middleware Config (#2188)

* ✨ Add customTags in logger middleware Config

* improve tags with parameter

* improve logger performance

* improve logger performance

* improve logger performance

* improve logger performance

Co-authored-by: René Werner <rene@gofiber.io>

.github/README.md

@@ -692,7 +692,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_ckb.md

@@ -691,7 +691,6 @@ For more articles, middlewares, examples or tools check our [awesome list](https
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_de.md

@@ -661,7 +661,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_es.md

@@ -661,7 +661,6 @@ Copyright (c) 2019-presente [Fenny](https://github.com/fenny) y [contribuyentes]
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_fa.md

@@ -813,7 +813,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_fr.md

@@ -663,7 +663,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_he.md

@@ -838,7 +838,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_id.md

@@ -664,7 +664,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_it.md

@@ -687,7 +687,6 @@ Copyright (c) 2019-ora [Fenny](https://github.com/fenny) e [Contributors](https:
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_ja.md

@@ -666,7 +666,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_ko.md

@@ -667,7 +667,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_nl.md

@@ -667,7 +667,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_pt.md

@@ -663,7 +663,6 @@ O logo oficial foi criado por [Vic Shóstak](https://github.com/koddr) e distrib
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_ru.md

@@ -670,7 +670,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_sa.md

@@ -732,7 +732,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_tr.md

@@ -660,7 +660,6 @@ Telif (c) 2019-günümüz [Fenny](https://github.com/fenny) ve [katkıda bulunan
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_zh-CN.md

@@ -670,7 +670,6 @@ Copyright (c) 2019-present [Fenny](https://github.com/fenny) and [Contributors](
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

.github/README_zh-TW.md

@@ -663,7 +663,6 @@ Fiber 是一個以贊助維生的開源專案，像是: 網域、gitbook、netli
 -   [fasthttp](https://github.com/valyala/fasthttp/blob/master/LICENSE)
 -   [bytebufferpool](https://github.com/valyala/bytebufferpool/blob/master/LICENSE)
 -   [dictpool](https://github.com/savsgio/dictpool/blob/master/LICENSE)
--   [fasttemplate](https://github.com/valyala/fasttemplate/blob/master/LICENSE)
 -   [fwd](https://github.com/philhofer/fwd/blob/master/LICENSE.md)
 -   [go-ole](https://github.com/go-ole/go-ole/blob/master/LICENSE)
 -   [gopsutil](https://github.com/shirou/gopsutil/blob/master/LICENSE)

internal/fasttemplate/LICENSE

@@ -1,22 +0,0 @@
-The MIT License (MIT)
-
-Copyright (c) 2015 Aliaksandr Valialkin
-
-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.
-

internal/fasttemplate/template.go

@@ -1,437 +0,0 @@
-// Package fasttemplate implements simple and fast template library.
-//
-// Fasttemplate is faster than text/template, strings.Replace
-// and strings.Replacer.
-//
-// Fasttemplate ideally fits for fast and simple placeholders' substitutions.
-package fasttemplate
-
-import (
-	"bytes"
-	"fmt"
-	"io"
-
-	"github.com/gofiber/fiber/v2/internal/bytebufferpool"
-)
-
-// ExecuteFunc calls f on each template tag (placeholder) occurrence.
-//
-// Returns the number of bytes written to w.
-//
-// This function is optimized for constantly changing templates.
-// Use Template.ExecuteFunc for frozen templates.
-func ExecuteFunc(template, startTag, endTag string, w io.Writer, f TagFunc) (int64, error) {
-	s := unsafeString2Bytes(template)
-	a := unsafeString2Bytes(startTag)
-	b := unsafeString2Bytes(endTag)
-
-	var nn int64
-	var ni int
-	var err error
-	for {
-		n := bytes.Index(s, a)
-		if n < 0 {
-			break
-		}
-		ni, err = w.Write(s[:n])
-		nn += int64(ni)
-		if err != nil {
-			return nn, err
-		}
-
-		s = s[n+len(a):]
-		n = bytes.Index(s, b)
-		if n < 0 {
-			// cannot find end tag - just write it to the output.
-			ni, _ = w.Write(a)
-			nn += int64(ni)
-			break
-		}
-
-		ni, err = f(w, unsafeBytes2String(s[:n]))
-		nn += int64(ni)
-		if err != nil {
-			return nn, err
-		}
-		s = s[n+len(b):]
-	}
-	ni, err = w.Write(s)
-	nn += int64(ni)
-
-	return nn, err
-}
-
-// Execute substitutes template tags (placeholders) with the corresponding
-// values from the map m and writes the result to the given writer w.
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// Returns the number of bytes written to w.
-//
-// This function is optimized for constantly changing templates.
-// Use Template.Execute for frozen templates.
-func Execute(template, startTag, endTag string, w io.Writer, m map[string]interface{}) (int64, error) {
-	return ExecuteFunc(template, startTag, endTag, w, func(w io.Writer, tag string) (int, error) { return stdTagFunc(w, tag, m) })
-}
-
-// ExecuteStd works the same way as Execute, but keeps the unknown placeholders.
-// This can be used as a drop-in replacement for strings.Replacer
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// Returns the number of bytes written to w.
-//
-// This function is optimized for constantly changing templates.
-// Use Template.ExecuteStd for frozen templates.
-func ExecuteStd(template, startTag, endTag string, w io.Writer, m map[string]interface{}) (int64, error) {
-	return ExecuteFunc(template, startTag, endTag, w, func(w io.Writer, tag string) (int, error) { return keepUnknownTagFunc(w, startTag, endTag, tag, m) })
-}
-
-// ExecuteFuncString calls f on each template tag (placeholder) occurrence
-// and substitutes it with the data written to TagFunc's w.
-//
-// Returns the resulting string.
-//
-// This function is optimized for constantly changing templates.
-// Use Template.ExecuteFuncString for frozen templates.
-func ExecuteFuncString(template, startTag, endTag string, f TagFunc) string {
-	s, err := ExecuteFuncStringWithErr(template, startTag, endTag, f)
-	if err != nil {
-		panic(fmt.Sprintf("unexpected error: %s", err))
-	}
-	return s
-}
-
-// ExecuteFuncStringWithErr is nearly the same as ExecuteFuncString
-// but when f returns an error, ExecuteFuncStringWithErr won't panic like ExecuteFuncString
-// it just returns an empty string and the error f returned
-func ExecuteFuncStringWithErr(template, startTag, endTag string, f TagFunc) (string, error) {
-	tagsCount := bytes.Count(unsafeString2Bytes(template), unsafeString2Bytes(startTag))
-	if tagsCount == 0 {
-		return template, nil
-	}
-
-	bb := byteBufferPool.Get()
-	if _, err := ExecuteFunc(template, startTag, endTag, bb, f); err != nil {
-		bb.Reset()
-		byteBufferPool.Put(bb)
-		return "", err
-	}
-	s := string(bb.B)
-	bb.Reset()
-	byteBufferPool.Put(bb)
-	return s, nil
-}
-
-var byteBufferPool bytebufferpool.Pool
-
-// ExecuteString substitutes template tags (placeholders) with the corresponding
-// values from the map m and returns the result.
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// This function is optimized for constantly changing templates.
-// Use Template.ExecuteString for frozen templates.
-func ExecuteString(template, startTag, endTag string, m map[string]interface{}) string {
-	return ExecuteFuncString(template, startTag, endTag, func(w io.Writer, tag string) (int, error) { return stdTagFunc(w, tag, m) })
-}
-
-// ExecuteStringStd works the same way as ExecuteString, but keeps the unknown placeholders.
-// This can be used as a drop-in replacement for strings.Replacer
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// This function is optimized for constantly changing templates.
-// Use Template.ExecuteStringStd for frozen templates.
-func ExecuteStringStd(template, startTag, endTag string, m map[string]interface{}) string {
-	return ExecuteFuncString(template, startTag, endTag, func(w io.Writer, tag string) (int, error) { return keepUnknownTagFunc(w, startTag, endTag, tag, m) })
-}
-
-// Template implements simple template engine, which can be used for fast
-// tags' (aka placeholders) substitution.
-type Template struct {
-	template string
-	startTag string
-	endTag   string
-
-	texts          [][]byte
-	tags           []string
-	byteBufferPool bytebufferpool.Pool
-}
-
-// New parses the given template using the given startTag and endTag
-// as tag start and tag end.
-//
-// The returned template can be executed by concurrently running goroutines
-// using Execute* methods.
-//
-// New panics if the given template cannot be parsed. Use NewTemplate instead
-// if template may contain errors.
-func New(template, startTag, endTag string) *Template {
-	t, err := NewTemplate(template, startTag, endTag)
-	if err != nil {
-		panic(err)
-	}
-	return t
-}
-
-// NewTemplate parses the given template using the given startTag and endTag
-// as tag start and tag end.
-//
-// The returned template can be executed by concurrently running goroutines
-// using Execute* methods.
-func NewTemplate(template, startTag, endTag string) (*Template, error) {
-	var t Template
-	err := t.Reset(template, startTag, endTag)
-	if err != nil {
-		return nil, err
-	}
-	return &t, nil
-}
-
-// TagFunc can be used as a substitution value in the map passed to Execute*.
-// Execute* functions pass tag (placeholder) name in 'tag' argument.
-//
-// TagFunc must be safe to call from concurrently running goroutines.
-//
-// TagFunc must write contents to w and return the number of bytes written.
-type TagFunc func(w io.Writer, tag string) (int, error)
-
-// Reset resets the template t to new one defined by
-// template, startTag and endTag.
-//
-// Reset allows Template object re-use.
-//
-// Reset may be called only if no other goroutines call t methods at the moment.
-func (t *Template) Reset(template, startTag, endTag string) error {
-	// Keep these vars in t, so GC won't collect them and won't break
-	// vars derived via unsafe*
-	t.template = template
-	t.startTag = startTag
-	t.endTag = endTag
-	t.texts = t.texts[:0]
-	t.tags = t.tags[:0]
-
-	if len(startTag) == 0 {
-		panic("startTag cannot be empty")
-	}
-	if len(endTag) == 0 {
-		panic("endTag cannot be empty")
-	}
-
-	s := unsafeString2Bytes(template)
-	a := unsafeString2Bytes(startTag)
-	b := unsafeString2Bytes(endTag)
-
-	tagsCount := bytes.Count(s, a)
-	if tagsCount == 0 {
-		return nil
-	}
-
-	if tagsCount+1 > cap(t.texts) {
-		t.texts = make([][]byte, 0, tagsCount+1)
-	}
-	if tagsCount > cap(t.tags) {
-		t.tags = make([]string, 0, tagsCount)
-	}
-
-	for {
-		n := bytes.Index(s, a)
-		if n < 0 {
-			t.texts = append(t.texts, s)
-			break
-		}
-		t.texts = append(t.texts, s[:n])
-
-		s = s[n+len(a):]
-		n = bytes.Index(s, b)
-		if n < 0 {
-			return fmt.Errorf("cannot find end tag=%q in the template=%q starting from %q", endTag, template, s)
-		}
-
-		t.tags = append(t.tags, unsafeBytes2String(s[:n]))
-		s = s[n+len(b):]
-	}
-
-	return nil
-}
-
-// ExecuteFunc calls f on each template tag (placeholder) occurrence.
-//
-// Returns the number of bytes written to w.
-//
-// This function is optimized for frozen templates.
-// Use ExecuteFunc for constantly changing templates.
-func (t *Template) ExecuteFunc(w io.Writer, f TagFunc) (int64, error) {
-	var nn int64
-
-	n := len(t.texts) - 1
-	if n == -1 {
-		ni, err := w.Write(unsafeString2Bytes(t.template))
-		return int64(ni), err
-	}
-
-	for i := 0; i < n; i++ {
-		ni, err := w.Write(t.texts[i])
-		nn += int64(ni)
-		if err != nil {
-			return nn, err
-		}
-
-		ni, err = f(w, t.tags[i])
-		nn += int64(ni)
-		if err != nil {
-			return nn, err
-		}
-	}
-	ni, err := w.Write(t.texts[n])
-	nn += int64(ni)
-	return nn, err
-}
-
-// Execute substitutes template tags (placeholders) with the corresponding
-// values from the map m and writes the result to the given writer w.
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// Returns the number of bytes written to w.
-func (t *Template) Execute(w io.Writer, m map[string]interface{}) (int64, error) {
-	return t.ExecuteFunc(w, func(w io.Writer, tag string) (int, error) { return stdTagFunc(w, tag, m) })
-}
-
-// ExecuteStd works the same way as Execute, but keeps the unknown placeholders.
-// This can be used as a drop-in replacement for strings.Replacer
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// Returns the number of bytes written to w.
-func (t *Template) ExecuteStd(w io.Writer, m map[string]interface{}) (int64, error) {
-	return t.ExecuteFunc(w, func(w io.Writer, tag string) (int, error) { return keepUnknownTagFunc(w, t.startTag, t.endTag, tag, m) })
-}
-
-// ExecuteFuncString calls f on each template tag (placeholder) occurrence
-// and substitutes it with the data written to TagFunc's w.
-//
-// Returns the resulting string.
-//
-// This function is optimized for frozen templates.
-// Use ExecuteFuncString for constantly changing templates.
-func (t *Template) ExecuteFuncString(f TagFunc) string {
-	s, err := t.ExecuteFuncStringWithErr(f)
-	if err != nil {
-		panic(fmt.Sprintf("unexpected error: %s", err))
-	}
-	return s
-}
-
-// ExecuteFuncStringWithErr calls f on each template tag (placeholder) occurrence
-// and substitutes it with the data written to TagFunc's w.
-//
-// Returns the resulting string.
-//
-// This function is optimized for frozen templates.
-// Use ExecuteFuncString for constantly changing templates.
-func (t *Template) ExecuteFuncStringWithErr(f TagFunc) (string, error) {
-	bb := t.byteBufferPool.Get()
-	if _, err := t.ExecuteFunc(bb, f); err != nil {
-		bb.Reset()
-		t.byteBufferPool.Put(bb)
-		return "", err
-	}
-	s := string(bb.Bytes())
-	bb.Reset()
-	t.byteBufferPool.Put(bb)
-	return s, nil
-}
-
-// ExecuteString substitutes template tags (placeholders) with the corresponding
-// values from the map m and returns the result.
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// This function is optimized for frozen templates.
-// Use ExecuteString for constantly changing templates.
-func (t *Template) ExecuteString(m map[string]interface{}) string {
-	return t.ExecuteFuncString(func(w io.Writer, tag string) (int, error) { return stdTagFunc(w, tag, m) })
-}
-
-// ExecuteStringStd works the same way as ExecuteString, but keeps the unknown placeholders.
-// This can be used as a drop-in replacement for strings.Replacer
-//
-// Substitution map m may contain values with the following types:
-//   - []byte - the fastest value type
-//   - string - convenient value type
-//   - TagFunc - flexible value type
-//
-// This function is optimized for frozen templates.
-// Use ExecuteStringStd for constantly changing templates.
-func (t *Template) ExecuteStringStd(m map[string]interface{}) string {
-	return t.ExecuteFuncString(func(w io.Writer, tag string) (int, error) { return keepUnknownTagFunc(w, t.startTag, t.endTag, tag, m) })
-}
-
-func stdTagFunc(w io.Writer, tag string, m map[string]interface{}) (int, error) {
-	v := m[tag]
-	if v == nil {
-		return 0, nil
-	}
-	switch value := v.(type) {
-	case []byte:
-		return w.Write(value)
-	case string:
-		return w.Write([]byte(value))
-	case TagFunc:
-		return value(w, tag)
-	default:
-		panic(fmt.Sprintf("tag=%q contains unexpected value type=%#v. Expected []byte, string or TagFunc", tag, v))
-	}
-}
-
-func keepUnknownTagFunc(w io.Writer, startTag, endTag, tag string, m map[string]interface{}) (int, error) {
-	v, ok := m[tag]
-	if !ok {
-		if _, err := w.Write(unsafeString2Bytes(startTag)); err != nil {
-			return 0, err
-		}
-		if _, err := w.Write(unsafeString2Bytes(tag)); err != nil {
-			return 0, err
-		}
-		if _, err := w.Write(unsafeString2Bytes(endTag)); err != nil {
-			return 0, err
-		}
-		return len(startTag) + len(tag) + len(endTag), nil
-	}
-	if v == nil {
-		return 0, nil
-	}
-	switch value := v.(type) {
-	case []byte:
-		return w.Write(value)
-	case string:
-		return w.Write([]byte(value))
-	case TagFunc:
-		return value(w, tag)
-	default:
-		panic(fmt.Sprintf("tag=%q contains unexpected value type=%#v. Expected []byte, string or TagFunc", tag, v))
-	}
-}

internal/fasttemplate/unsafe.go

@@ -1,22 +0,0 @@
-//go:build !appengine
-// +build !appengine
-
-package fasttemplate
-
-import (
-	"reflect"
-	"unsafe"
-)
-
-func unsafeBytes2String(b []byte) string {
-	return *(*string)(unsafe.Pointer(&b))
-}
-
-func unsafeString2Bytes(s string) (b []byte) {
-	sh := (*reflect.StringHeader)(unsafe.Pointer(&s))
-	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
-	bh.Data = sh.Data
-	bh.Cap = sh.Len
-	bh.Len = sh.Len
-	return b
-}

internal/fasttemplate/unsafe_gae.go

@@ -1,12 +0,0 @@
-//go:build appengine
-// +build appengine
-
-package fasttemplate
-
-func unsafeBytes2String(b []byte) string {
-	return string(b)
-}
-
-func unsafeString2Bytes(s string) []byte {
-	return []byte(s)
-}

middleware/logger/README.md

@@ -11,6 +11,7 @@ Logger middleware for [Fiber](https://github.com/gofiber/fiber) that logs HTTP r
 		- [Logging Request ID](#logging-request-id)
 		- [Changing TimeZone & TimeFormat](#changing-timezone--timeformat)
 		- [Custom File Writer](#custom-file-writer)
+        - [Add Custom Tags](#add-custom-tags)
 	- [Config](#config)
 	- [Default Config](#default-config-1)
 	- [Constants](#constants)
@@ -75,6 +76,16 @@ app.Use(logger.New(logger.Config{
 	Output: file,
 }))
 ```
+### Add Custom Tags
+```go
+app.Use(logger.New(logger.Config{
+	CustomTags: map[string]logger.LogFunc{
+		"custom_tag": func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString("it is a custom tag")
+		},
+	},
+}))
+```
 
 ## Config
 ```go
@@ -85,6 +96,11 @@ type Config struct {
 	// Optional. Default: nil
 	Next func(c *fiber.Ctx) bool
 
+	// CustomTags defines the custom tag action
+	//
+	// Optional. Default: map[string]LogFunc{}
+	CustomTags map[string]LogFunc
+	
 	// Format defines the logging tags
 	//
 	// Optional. Default: [${time}] ${status} - ${latency} ${method} ${path}\n

middleware/logger/config.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/gofiber/fiber/v2"
+	"github.com/gofiber/fiber/v2/internal/bytebufferpool"
 )
 
 // Config defines the config for middleware.
@@ -22,6 +23,11 @@ type Config struct {
 	// Optional. Default: a function that does nothing.
 	Done func(c *fiber.Ctx, logString []byte)
 
+	// tagFunctions defines the custom tag action
+	//
+	// Optional. Default: map[string]LogFunc
+	CustomTags map[string]LogFunc
+
 	// Format defines the logging tags
 	//
 	// Optional. Default: [${time}] ${status} - ${latency} ${method} ${path}\n
@@ -52,6 +58,14 @@ type Config struct {
 	timeZoneLocation *time.Location
 }
 
+const (
+	startTag       = "${"
+	endTag         = "}"
+	paramSeparator = ":"
+)
+
+type LogFunc func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error)
+
 // ConfigDefault is the default config
 var ConfigDefault = Config{
 	Next:         nil,
@@ -65,11 +79,8 @@ var ConfigDefault = Config{
 }
 
 // Function to check if the logger format is compatible for coloring
-func validCustomFormat(format string) bool {
+func checkColorEnable(format string) bool {
 	validTemplates := []string{"${status}", "${method}"}
-	if format == "" {
-		return true
-	}
 	for _, template := range validTemplates {
 		if strings.Contains(format, template) {
 			return true
@@ -88,11 +99,6 @@ func configDefault(config ...Config) Config {
 	// Override default config
 	cfg := config[0]
 
-	// Enable colors if no custom format or output is given
-	if validCustomFormat(cfg.Format) && cfg.Output == nil {
-		cfg.enableColors = true
-	}
-
 	// Set default values
 	if cfg.Next == nil {
 		cfg.Next = ConfigDefault.Next
@@ -103,6 +109,7 @@ func configDefault(config ...Config) Config {
 	if cfg.Format == "" {
 		cfg.Format = ConfigDefault.Format
 	}
+
 	if cfg.TimeZone == "" {
 		cfg.TimeZone = ConfigDefault.TimeZone
 	}
@@ -115,5 +122,11 @@ func configDefault(config ...Config) Config {
 	if cfg.Output == nil {
 		cfg.Output = ConfigDefault.Output
 	}
+
+	// Enable colors if no custom format or output is given
+	if cfg.Output == nil && checkColorEnable(cfg.Format) {
+		cfg.enableColors = true
+	}
+
 	return cfg
 }

middleware/logger/data.go

@@ -0,0 +1,19 @@
+package logger
+
+import (
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+var DataPool = sync.Pool{New: func() interface{} { return new(Data) }}
+
+// Data is a struct to define some variables to use in custom logger function.
+type Data struct {
+	Pid           string
+	ErrPaddingStr string
+	ChainErr      error
+	Start         time.Time
+	Stop          time.Time
+	Timestamp     atomic.Value
+}

middleware/logger/logger.go

@@ -2,7 +2,6 @@ package logger
 
 import (
 	"fmt"
-	"io"
 	"os"
 	"strconv"
 	"strings"
@@ -10,56 +9,13 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/gofiber/fiber/v2"
+	"github.com/gofiber/fiber/v2/utils"
 	"github.com/mattn/go-colorable"
 	"github.com/mattn/go-isatty"
 	"github.com/valyala/fasthttp"
 
-	"github.com/gofiber/fiber/v2"
 	"github.com/gofiber/fiber/v2/internal/bytebufferpool"
-	"github.com/gofiber/fiber/v2/internal/fasttemplate"
-)
-
-// Logger variables
-const (
-	TagPid               = "pid"
-	TagTime              = "time"
-	TagReferer           = "referer"
-	TagProtocol          = "protocol"
-	TagPort              = "port"
-	TagIP                = "ip"
-	TagIPs               = "ips"
-	TagHost              = "host"
-	TagMethod            = "method"
-	TagPath              = "path"
-	TagURL               = "url"
-	TagUA                = "ua"
-	TagLatency           = "latency"
-	TagStatus            = "status"
-	TagResBody           = "resBody"
-	TagReqHeaders        = "reqHeaders"
-	TagQueryStringParams = "queryParams"
-	TagBody              = "body"
-	TagBytesSent         = "bytesSent"
-	TagBytesReceived     = "bytesReceived"
-	TagRoute             = "route"
-	TagError             = "error"
-	// DEPRECATED: Use TagReqHeader instead
-	TagHeader     = "header:"
-	TagReqHeader  = "reqHeader:"
-	TagRespHeader = "respHeader:"
-	TagLocals     = "locals:"
-	TagQuery      = "query:"
-	TagForm       = "form:"
-	TagCookie     = "cookie:"
-	TagBlack      = "black"
-	TagRed        = "red"
-	TagGreen      = "green"
-	TagYellow     = "yellow"
-	TagBlue       = "blue"
-	TagMagenta    = "magenta"
-	TagCyan       = "cyan"
-	TagWhite      = "white"
-	TagReset      = "reset"
 )
 
 // New creates a new middleware handler
@@ -76,17 +32,14 @@ func New(config ...Config) fiber.Handler {
 	}
 
 	// Check if format contains latency
-	cfg.enableLatency = strings.Contains(cfg.Format, "${latency}")
+	cfg.enableLatency = strings.Contains(cfg.Format, "${"+TagLatency+"}")
 
-	// Create template parser
-	tmpl := fasttemplate.New(cfg.Format, "${", "}")
-
-	// Create correct timeformat
 	var timestamp atomic.Value
+	// Create correct timeformat
 	timestamp.Store(time.Now().In(cfg.timeZoneLocation).Format(cfg.TimeFormat))
 
 	// Update date/time every 500 milliseconds in a separate go routine
-	if strings.Contains(cfg.Format, "${time}") {
+	if strings.Contains(cfg.Format, "${"+TagTime+"}") {
 		go func() {
 			for {
 				time.Sleep(cfg.TimeInterval)
@@ -114,6 +67,14 @@ func New(config ...Config) fiber.Handler {
 	}
 	errPadding := 15
 	errPaddingStr := strconv.Itoa(errPadding)
+
+	// instead of analyzing the template inside(handler) each time, this is done once before
+	// and we create several slices of the same length with the functions to be executed and fixed parts.
+	templateChain, logFunChain, err := buildLogFuncChain(&cfg, createTagMap(&cfg))
+	if err != nil {
+		panic(err)
+	}
+
 	// Return new handler
 	return func(c *fiber.Ctx) (err error) {
 		// Don't execute middleware if Next returns true
@@ -140,16 +101,24 @@ func New(config ...Config) fiber.Handler {
 			errHandler = c.App().ErrorHandler
 		})
 
-		var start, stop time.Time
+		// Logger data
+		data := DataPool.Get().(*Data)
+		// no need for a reset, as long as we always override everything
+		data.Pid = pid
+		data.ErrPaddingStr = errPaddingStr
+		data.Timestamp = timestamp
+		// put data back in the pool
+		defer DataPool.Put(data)
 
 		// Set latency start time
 		if cfg.enableLatency {
-			start = time.Now()
+			data.Start = time.Now()
 		}
 
 		// Handle request, store err for logging
 		chainErr := c.Next()
 
+		data.ChainErr = chainErr
 		// Manually call error handler
 		if chainErr != nil {
 			if err := errHandler(c, chainErr); err != nil {
@@ -159,7 +128,7 @@ func New(config ...Config) fiber.Handler {
 
 		// Set latency stop time
 		if cfg.enableLatency {
-			stop = time.Now()
+			data.Stop = time.Now()
 		}
 
 		// Get new buffer
@@ -177,7 +146,7 @@ func New(config ...Config) fiber.Handler {
 			_, _ = buf.WriteString(fmt.Sprintf("%s |%s %3d %s| %7v | %15s |%s %-7s %s| %-"+errPaddingStr+"s %s\n",
 				timestamp.Load().(string),
 				statusColor(c.Response().StatusCode(), colors), c.Response().StatusCode(), colors.Reset,
-				stop.Sub(start).Round(time.Millisecond),
+				data.Stop.Sub(data.Start).Round(time.Millisecond),
 				c.IP(),
 				methodColor(c.Method(), colors), c.Method(), colors.Reset,
 				c.Path(),
@@ -196,114 +165,20 @@ func New(config ...Config) fiber.Handler {
 			return nil
 		}
 
-		// Loop over template tags to replace it with the correct value
+		// Loop over template parts execute dynamic parts and add fixed parts to the buffer
-		_, err = tmpl.ExecuteFunc(buf, func(w io.Writer, tag string) (int, error) {
+		for i, logFunc := range logFunChain {
-			switch tag {
+			if logFunc == nil {
-			case TagTime:
+				_, _ = buf.Write(templateChain[i])
-				return buf.WriteString(timestamp.Load().(string))
+			} else if templateChain[i] == nil {
-			case TagReferer:
+				_, err = logFunc(buf, c, data, "")
-				return buf.WriteString(c.Get(fiber.HeaderReferer))
+			} else {
-			case TagProtocol:
+				_, err = logFunc(buf, c, data, utils.UnsafeString(templateChain[i]))
-				return buf.WriteString(c.Protocol())
-			case TagPid:
-				return buf.WriteString(pid)
-			case TagPort:
-				return buf.WriteString(c.Port())
-			case TagIP:
-				return buf.WriteString(c.IP())
-			case TagIPs:
-				return buf.WriteString(c.Get(fiber.HeaderXForwardedFor))
-			case TagHost:
-				return buf.WriteString(c.Hostname())
-			case TagPath:
-				return buf.WriteString(c.Path())
-			case TagURL:
-				return buf.WriteString(c.OriginalURL())
-			case TagUA:
-				return buf.WriteString(c.Get(fiber.HeaderUserAgent))
-			case TagLatency:
-				return buf.WriteString(fmt.Sprintf("%7v", stop.Sub(start).Round(time.Millisecond)))
-			case TagBody:
-				return buf.Write(c.Body())
-			case TagBytesReceived:
-				return appendInt(buf, len(c.Request().Body()))
-			case TagBytesSent:
-				return appendInt(buf, len(c.Response().Body()))
-			case TagRoute:
-				return buf.WriteString(c.Route().Path)
-			case TagStatus:
-				if cfg.enableColors {
-					return buf.WriteString(fmt.Sprintf("%s %3d %s", statusColor(c.Response().StatusCode(), colors), c.Response().StatusCode(), colors.Reset))
-				}
-				return appendInt(buf, c.Response().StatusCode())
-			case TagResBody:
-				return buf.Write(c.Response().Body())
-			case TagReqHeaders:
-				reqHeaders := make([]string, 0)
-				for k, v := range c.GetReqHeaders() {
-					reqHeaders = append(reqHeaders, k+"="+v)
-				}
-				return buf.Write([]byte(strings.Join(reqHeaders, "&")))
-			case TagQueryStringParams:
-				return buf.WriteString(c.Request().URI().QueryArgs().String())
-			case TagMethod:
-				if cfg.enableColors {
-					return buf.WriteString(fmt.Sprintf("%s %-7s %s", methodColor(c.Method(), colors), c.Method(), colors.Reset))
-				}
-				return buf.WriteString(c.Method())
-			case TagBlack:
-				return buf.WriteString(colors.Black)
-			case TagRed:
-				return buf.WriteString(colors.Red)
-			case TagGreen:
-				return buf.WriteString(colors.Green)
-			case TagYellow:
-				return buf.WriteString(colors.Yellow)
-			case TagBlue:
-				return buf.WriteString(colors.Blue)
-			case TagMagenta:
-				return buf.WriteString(colors.Magenta)
-			case TagCyan:
-				return buf.WriteString(colors.Cyan)
-			case TagWhite:
-				return buf.WriteString(colors.White)
-			case TagReset:
-				return buf.WriteString(colors.Reset)
-			case TagError:
-				if chainErr != nil {
-					return buf.WriteString(chainErr.Error())
-				}
-				return buf.WriteString("-")
-			default:
-				// Check if we have a value tag i.e.: "reqHeader:x-key"
-				switch {
-				case strings.HasPrefix(tag, TagReqHeader):
-					return buf.WriteString(c.Get(tag[10:]))
-				case strings.HasPrefix(tag, TagHeader):
-					return buf.WriteString(c.Get(tag[7:]))
-				case strings.HasPrefix(tag, TagRespHeader):
-					return buf.WriteString(c.GetRespHeader(tag[11:]))
-				case strings.HasPrefix(tag, TagQuery):
-					return buf.WriteString(c.Query(tag[6:]))
-				case strings.HasPrefix(tag, TagForm):
-					return buf.WriteString(c.FormValue(tag[5:]))
-				case strings.HasPrefix(tag, TagCookie):
-					return buf.WriteString(c.Cookies(tag[7:]))
-				case strings.HasPrefix(tag, TagLocals):
-					switch v := c.Locals(tag[7:]).(type) {
-					case []byte:
-						return buf.Write(v)
-					case string:
-						return buf.WriteString(v)
-					case nil:
-						return 0, nil
-					default:
-						return buf.WriteString(fmt.Sprintf("%v", v))
-					}
-				}
 			}
-			return 0, nil
+			if err != nil {
-		})
+				break
+			}
+		}
+
 		// Also write errors to the buffer
 		if err != nil {
 			_, _ = buf.WriteString(err.Error())

middleware/logger/logger_test.go

@@ -287,30 +287,59 @@ func Test_Logger_Data_Race(t *testing.T) {
 
 // go test -v -run=^$ -bench=Benchmark_Logger -benchmem -count=4
 func Benchmark_Logger(b *testing.B) {
-	app := fiber.New()
+	benchSetup := func(bb *testing.B, app *fiber.App) {
+		h := app.Handler()
 
-	app.Use(New(Config{
+		fctx := &fasthttp.RequestCtx{}
-		Format: "${bytesReceived} ${bytesSent} ${status}",
+		fctx.Request.Header.SetMethod("GET")
-		Output: io.Discard,
+		fctx.Request.SetRequestURI("/")
-	}))
-	app.Get("/", func(c *fiber.Ctx) error {
-		return c.SendString("Hello, World!")
-	})
 
-	h := app.Handler()
+		bb.ReportAllocs()
+		bb.ResetTimer()
 
-	fctx := &fasthttp.RequestCtx{}
+		for n := 0; n < bb.N; n++ {
-	fctx.Request.Header.SetMethod("GET")
+			h(fctx)
-	fctx.Request.SetRequestURI("/")
+		}
 
-	b.ReportAllocs()
+		utils.AssertEqual(bb, 200, fctx.Response.Header.StatusCode())
-	b.ResetTimer()
-
-	for n := 0; n < b.N; n++ {
-		h(fctx)
 	}
 
-	utils.AssertEqual(b, 200, fctx.Response.Header.StatusCode())
+	b.Run("Base", func(bb *testing.B) {
+		app := fiber.New()
+		app.Use(New(Config{
+			Format: "${bytesReceived} ${bytesSent} ${status}",
+			Output: io.Discard,
+		}))
+		app.Get("/", func(c *fiber.Ctx) error {
+			c.Set("test", "test")
+			return c.SendString("Hello, World!")
+		})
+		benchSetup(bb, app)
+	})
+
+	b.Run("DefaultFormat", func(bb *testing.B) {
+		app := fiber.New()
+		app.Use(New(Config{
+			Output: io.Discard,
+		}))
+		app.Get("/", func(c *fiber.Ctx) error {
+			return c.SendString("Hello, World!")
+		})
+		benchSetup(bb, app)
+	})
+
+	b.Run("WithTagParameter", func(bb *testing.B) {
+		app := fiber.New()
+		app.Use(New(Config{
+			Format: "${bytesReceived} ${bytesSent} ${status} ${reqHeader:test}",
+			Output: io.Discard,
+		}))
+		app.Get("/", func(c *fiber.Ctx) error {
+			c.Set("test", "test")
+			return c.SendString("Hello, World!")
+		})
+		benchSetup(bb, app)
+	})
 }
 
 // go test -run Test_Response_Header
@@ -383,3 +412,32 @@ func Test_ReqHeader_Header(t *testing.T) {
 	utils.AssertEqual(t, fiber.StatusOK, resp.StatusCode)
 	utils.AssertEqual(t, "Hello fiber!", buf.String())
 }
+
+// go test -run Test_CustomTags
+func Test_CustomTags(t *testing.T) {
+	customTag := "it is a custom tag"
+
+	buf := bytebufferpool.Get()
+	defer bytebufferpool.Put(buf)
+
+	app := fiber.New()
+	app.Use(New(Config{
+		Format: "${custom_tag}",
+		CustomTags: map[string]LogFunc{
+			"custom_tag": func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+				return buf.WriteString(customTag)
+			},
+		},
+		Output: buf,
+	}))
+	app.Get("/", func(c *fiber.Ctx) error {
+		return c.SendString("Hello fiber!")
+	})
+	reqHeaderReq := httptest.NewRequest("GET", "/", nil)
+	reqHeaderReq.Header.Add("test", "Hello fiber!")
+	resp, err := app.Test(reqHeaderReq)
+
+	utils.AssertEqual(t, nil, err)
+	utils.AssertEqual(t, fiber.StatusOK, resp.StatusCode)
+	utils.AssertEqual(t, customTag, buf.String())
+}

middleware/logger/tags.go

@@ -0,0 +1,208 @@
+package logger
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/gofiber/fiber/v2"
+	"github.com/gofiber/fiber/v2/internal/bytebufferpool"
+)
+
+// Logger variables
+const (
+	TagPid               = "pid"
+	TagTime              = "time"
+	TagReferer           = "referer"
+	TagProtocol          = "protocol"
+	TagPort              = "port"
+	TagIP                = "ip"
+	TagIPs               = "ips"
+	TagHost              = "host"
+	TagMethod            = "method"
+	TagPath              = "path"
+	TagURL               = "url"
+	TagUA                = "ua"
+	TagLatency           = "latency"
+	TagStatus            = "status"
+	TagResBody           = "resBody"
+	TagReqHeaders        = "reqHeaders"
+	TagQueryStringParams = "queryParams"
+	TagBody              = "body"
+	TagBytesSent         = "bytesSent"
+	TagBytesReceived     = "bytesReceived"
+	TagRoute             = "route"
+	TagError             = "error"
+	// DEPRECATED: Use TagReqHeader instead
+	TagHeader     = "header:"
+	TagReqHeader  = "reqHeader:"
+	TagRespHeader = "respHeader:"
+	TagLocals     = "locals:"
+	TagQuery      = "query:"
+	TagForm       = "form:"
+	TagCookie     = "cookie:"
+	TagBlack      = "black"
+	TagRed        = "red"
+	TagGreen      = "green"
+	TagYellow     = "yellow"
+	TagBlue       = "blue"
+	TagMagenta    = "magenta"
+	TagCyan       = "cyan"
+	TagWhite      = "white"
+	TagReset      = "reset"
+)
+
+// createTagMap function merged the default with the custom tags
+func createTagMap(cfg *Config) map[string]LogFunc {
+	// Set default tags
+	tagFunctions := map[string]LogFunc{
+		TagReferer: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Get(fiber.HeaderReferer))
+		},
+		TagProtocol: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Protocol())
+		},
+		TagPort: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Port())
+		},
+		TagIP: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.IP())
+		},
+		TagIPs: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Get(fiber.HeaderXForwardedFor))
+		},
+		TagHost: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Hostname())
+		},
+		TagPath: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Path())
+		},
+		TagURL: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.OriginalURL())
+		},
+		TagUA: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Get(fiber.HeaderUserAgent))
+		},
+		TagBody: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.Write(c.Body())
+		},
+		TagBytesReceived: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return appendInt(buf, len(c.Request().Body()))
+		},
+		TagBytesSent: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return appendInt(buf, len(c.Response().Body()))
+		},
+		TagRoute: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Route().Path)
+		},
+		TagResBody: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.Write(c.Response().Body())
+		},
+		TagReqHeaders: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			reqHeaders := make([]string, 0)
+			for k, v := range c.GetReqHeaders() {
+				reqHeaders = append(reqHeaders, k+"="+v)
+			}
+			return buf.Write([]byte(strings.Join(reqHeaders, "&")))
+		},
+		TagQueryStringParams: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Request().URI().QueryArgs().String())
+		},
+
+		TagBlack: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Black)
+		},
+		TagRed: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Red)
+		},
+		TagGreen: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Green)
+		},
+		TagYellow: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Yellow)
+		},
+		TagBlue: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Blue)
+		},
+		TagMagenta: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Magenta)
+		},
+		TagCyan: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Cyan)
+		},
+		TagWhite: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.White)
+		},
+		TagReset: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.App().Config().ColorScheme.Reset)
+		},
+		TagError: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			if data.ChainErr != nil {
+				return buf.WriteString(data.ChainErr.Error())
+			}
+			return buf.WriteString("-")
+		},
+		TagReqHeader: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Get(extraParam))
+		},
+		TagHeader: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Get(extraParam))
+		},
+		TagRespHeader: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.GetRespHeader(extraParam))
+		},
+		TagQuery: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Query(extraParam))
+		},
+		TagForm: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.FormValue(extraParam))
+		},
+		TagCookie: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(c.Cookies(extraParam))
+		},
+		TagLocals: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			switch v := c.Locals(extraParam).(type) {
+			case []byte:
+				return buf.Write(v)
+			case string:
+				return buf.WriteString(v)
+			case nil:
+				return 0, nil
+			default:
+				return buf.WriteString(fmt.Sprintf("%v", v))
+			}
+		},
+		TagStatus: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			if cfg.enableColors {
+				colors := c.App().Config().ColorScheme
+				return buf.WriteString(fmt.Sprintf("%s %3d %s", statusColor(c.Response().StatusCode(), colors), c.Response().StatusCode(), colors.Reset))
+			}
+			return appendInt(buf, c.Response().StatusCode())
+		},
+		TagMethod: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			if cfg.enableColors {
+				colors := c.App().Config().ColorScheme
+				return buf.WriteString(fmt.Sprintf("%s %-7s %s", methodColor(c.Method(), colors), c.Method(), colors.Reset))
+			}
+			return buf.WriteString(c.Method())
+		},
+		TagPid: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(data.Pid)
+		},
+		TagLatency: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			latency := data.Stop.Sub(data.Start).Round(time.Millisecond)
+			return buf.WriteString(fmt.Sprintf("%7v", latency))
+		},
+		TagTime: func(buf *bytebufferpool.ByteBuffer, c *fiber.Ctx, data *Data, extraParam string) (int, error) {
+			return buf.WriteString(data.Timestamp.Load().(string))
+		},
+	}
+	// merge with custom tags from user
+	if cfg.CustomTags != nil {
+		for k, v := range cfg.CustomTags {
+			tagFunctions[k] = v
+		}
+	}
+
+	return tagFunctions
+}

middleware/logger/template_chain.go

@@ -0,0 +1,67 @@
+package logger
+
+import (
+	"bytes"
+	"errors"
+
+	"github.com/gofiber/fiber/v2/utils"
+)
+
+// buildLogFuncChain analyzes the template and creates slices with the functions for execution and
+// slices with the fixed parts of the template and the parameters
+//
+// fixParts contains the fixed parts of the template or parameters if a function is stored in the funcChain at this position
+// funcChain contains for the parts which exist the functions for the dynamic parts
+// funcChain and fixParts always have the same length and contain nil for the parts where no data is required in the chain,
+// if a function exists for the part, a parameter for it can also exist in the fixParts slice
+func buildLogFuncChain(cfg *Config, tagFunctions map[string]LogFunc) (fixParts [][]byte, funcChain []LogFunc, err error) {
+	// process flow is copied from the fasttemplate flow https://github.com/valyala/fasttemplate/blob/2a2d1afadadf9715bfa19683cdaeac8347e5d9f9/template.go#L23-L62
+	templateB := utils.UnsafeBytes(cfg.Format)
+	startTagB := utils.UnsafeBytes(startTag)
+	endTagB := utils.UnsafeBytes(endTag)
+	paramSeparatorB := utils.UnsafeBytes(paramSeparator)
+
+	for {
+		currentPos := bytes.Index(templateB, startTagB)
+		if currentPos < 0 {
+			// no starting tag found in the existing template part
+			break
+		}
+		// add fixed part
+		funcChain = append(funcChain, nil)
+		fixParts = append(fixParts, templateB[:currentPos])
+
+		templateB = templateB[currentPos+len(startTagB):]
+		currentPos = bytes.Index(templateB, endTagB)
+		if currentPos < 0 {
+			// cannot find end tag - just write it to the output.
+			funcChain = append(funcChain, nil)
+			fixParts = append(fixParts, startTagB)
+			break
+		}
+		// ## function block ##
+		// first check for tags with parameters
+		if index := bytes.Index(templateB[:currentPos], paramSeparatorB); index != -1 {
+			if logFunc, ok := tagFunctions[utils.UnsafeString(templateB[:index+1])]; ok {
+				funcChain = append(funcChain, logFunc)
+				// add param to the fixParts
+				fixParts = append(fixParts, templateB[index+1:currentPos])
+			} else {
+				return nil, nil, errors.New("No parameter found in \"" + utils.UnsafeString(templateB[:currentPos]) + "\"")
+			}
+		} else if logFunc, ok := tagFunctions[utils.UnsafeString(templateB[:currentPos])]; ok {
+			// add functions without parameter
+			funcChain = append(funcChain, logFunc)
+			fixParts = append(fixParts, nil)
+		}
+		// ## function block end ##
+
+		// reduce the template string
+		templateB = templateB[currentPos+len(endTagB):]
+	}
+	// set the rest
+	funcChain = append(funcChain, nil)
+	fixParts = append(fixParts, templateB)
+
+	return
+}