node-logfmt

install

npm install logfmt

use

var logfmt = require('logfmt');

logging

logfmt.log()

Defaults to logging to process.stdout

var logfmt = require('logfmt');
logfmt.log({ "foo": "bar", "a": 14, baz: 'hello kitty'})
//=> foo=bar a=14 baz="hello kitty"

customizing logging location

log() Accepts as 2nd arg anything that responds to write(string)

var logfmt = require('logfmt');
logfmt.log({ "foo": "bar", "a": 14, baz: 'hello kitty'}, process.stderr)
//=> foo=bar a=14 baz="hello kitty"

Overwrite the default location by setting .sink

var logfmt = require('logfmt');
logfmt.sink = process.stderr

logfmt.log({ "foo": "bar", "a": 14, baz: 'hello kitty'})
//=> foo=bar a=14 baz="hello kitty"

parser

logfmt.parse()

var logfmt = require('logfmt');

logfmt.parse("foo=bar a=14 baz=\"hello kitty\" cool%story=bro f %^asdf code=H12")
//=>{ "foo": "bar", "a": 14, "baz": "hello kitty", "cool%story": "bro", "f": true, "%^asdf": true, "code" : "H12" }

express middleware

logfmt.body_parser();

var logfmt   = require('logfmt').body_parser;

app.use(logfmt());

// req.body is now an array of objects
app.post('/logs', function(req, res){

  console.log('BODY: ' + JSON.stringify(req.body));

  req.body.forEach(function(data){
    console.log(data);
  });

  res.send('OK');
})

app.listen(3000)

test it:

curl -X POST --header 'Content-Type: application/logplex-1' -d "foo=bar a=14 baz=\"hello kitty\" cool%story=bro f %^asdf" http://localhost:3000/logs

command line

accepts lines on STDIN and converts them to json

echo "foo=bar a=14 baz=\"hello kitty\" cool%story=bro f %^asdf" | logfmt
{ "foo": "bar", "a": 14, "baz": "hello kitty", "cool%story": "bro", "f": true, "%^asdf": true }

reverse

accepts JSON on STDIN and converts them to logfmt

echo '{ "foo": "bar", "a": 14, "baz": "hello kitty", "cool%story": "bro", "f": true, "%^asdf": true }' | logfmt -r
foo=bar a=14 baz="hello kitty" cool%story=bro f=true %^asdf=true

echo "foo=bar a=14 baz=\"hello kitty\" cool%story=bro f %^asdf" | logfmt | logfmt -r | logfmt
{ "foo": "bar", "a": 14, "baz": "hello kitty", "cool%story": "bro", "f": true, "%^asdf": true }

caveats

I use a regex and haven't optimized much for performance yet.