Logsflags: g

Logfmt Key-Value Pair

Parse key=value pairs from logfmt-style log lines, supporting both quoted and unquoted values.

Available in

JavaScript / ECMAScript code

jsJavaScript

const re = new RegExp("([a-zA-Z_][\\w.]*)=(\"[^\"]*\"|\\S+)", "g");
const input = "level=info msg=\"user logged in\" user_id=42";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).

Python (re) code

pyPython

import re

pattern = re.compile(r"([a-zA-Z_][\\w.]*)=(\"[^\"]*\"|\\S+)")
input_text = "level=info msg=\"user logged in\" user_id=42"
for m in pattern.finditer(input_text):
    print(m.group(0))

Stdlib `re` module — no third-party dependency. Works on Python 3.6+.

Go (RE2) code

goGo

package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`([a-zA-Z_][\w.]*)=("[^"]*"|\S+)`)
	input := `level=info msg="user logged in" user_id=42`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}

Uses `regexp.MustCompile` (panics on bad patterns at startup) and `FindAllString` for all matches.

Pattern

regexengine-agnostic

([a-zA-Z_][\w.]*)=("[^"]*"|\S+)   (flags: g)

Raw source: ([a-zA-Z_][\w.]*)=("[^"]*"|\S+)

How it works

([a-zA-Z_][\w.]*) captures the key: starts with a letter or underscore, followed by word chars or dots. = is a literal separator. ("[^"]*"|\S+) captures the value: either a double-quoted string (allowing spaces inside) or an unquoted sequence of non-whitespace characters.