JSON deserialization benchmark

json_deserialization_bench_test.go

package main

//Results from below tests show why we've decided to use ffjson instead of json deserializer

import "testing"

import (
	"encoding/json"
)

//form https://randomuser.me/
var blob = []byte(`{
		"id": "unique-id",
		"user": {
				"email": "manuela.velasco50@example.com",
				"username": "heavybutterfly920",
				"password": "enterprise",
				"salt": "egEn6YsO",
				"md5": "2dd1894ea9d19bf5479992da95713a3a",
				"sha1": "ba230bc400723f470b68e9609ab7d0e6cf123b59",
				"registered": "1303647245",
				"dob": "415458547",
				"phone": "994-131-106",
				"cell": "626-695-164",
				"DNI": "52434048-I"
		}
}`)

var wrongBlob = []byte(`{"NOT JSON"...}`)

func BenchmarkJsonUnmarshal(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var userWithId UserWithId
		if err := json.Unmarshal(blob, &userWithId); err != nil {
			b.Log("%v %s\n", userWithId, err)
		}
	}
}

func BenchmarkFastJsonUnmarshal(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var userWithId UserWithId
		if err := userWithId.UnmarshalJSON(blob); err != nil {
			b.Log("%v %s\n", userWithId, err)
		}
	}
}

func BenchmarkJsonErrUnmarshal(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var userWithId UserWithId
		if err := json.Unmarshal(wrongBlob, &userWithId); err == nil {
			b.Log("Expected error but got nil")
		}
	}
}

func BenchmarkFastJsonErrUnmarshal(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var userWithId UserWithId
		if err := userWithId.UnmarshalJSON(wrongBlob); err == nil {
			b.Log("Expected error but got nil")
		}
	}
}

output

go test -bench=. -benchmem
testing: warning: no tests to run
PASS
BenchmarkJsonUnmarshal-4       	  100000	     15354 ns/op	    1875 B/op	      37 allocs/op
BenchmarkFastJsonUnmarshal-4   	  200000	      7200 ns/op	    1555 B/op	      31 allocs/op
BenchmarkJsonErrUnmarshal-4    	 2000000	      1027 ns/op	     384 B/op	       9 allocs/op
BenchmarkFastJsonErrUnmarshal-4	  500000	      2598 ns/op	     528 B/op	      13 allocs/op
ok  	stash.allegrogroup.com/test	7.606s

user.go

package main

type user map[string]string

type UserWithId struct {
	ID  string  `json:"id"`
	User user `json:"user"`
}

user_ffjson.go

// DO NOT EDIT!
// Code generated by ffjson <https://github.com/pquerna/ffjson>
// source: ../ALTT/metadata-service/model/user.go
// DO NOT EDIT!

package main

import (
	"bytes"
	"fmt"
	fflib "github.com/pquerna/ffjson/fflib/v1"
)

const (
	ffj_t_UserWithIdbase = iota
	ffj_t_UserWithIdno_such_key

	ffj_t_UserWithId_ID

	ffj_t_UserWithId_User
)

var ffj_key_UserWithId_ID = []byte("id")

var ffj_key_UserWithId_User = []byte("user")

func (uj *UserWithId) UnmarshalJSON(input []byte) error {
	fs := fflib.NewFFLexer(input)
	return uj.UnmarshalJSONFFLexer(fs, fflib.FFParse_map_start)
}

func (uj *UserWithId) UnmarshalJSONFFLexer(fs *fflib.FFLexer, state fflib.FFParseState) error {
	var err error = nil
	currentKey := ffj_t_UserWithIdbase
	_ = currentKey
	tok := fflib.FFTok_init
	wantedTok := fflib.FFTok_init

mainparse:
	for {
		tok = fs.Scan()
		//	println(fmt.Sprintf("debug: tok: %v  state: %v", tok, state))
		if tok == fflib.FFTok_error {
			goto tokerror
		}

		switch state {

		case fflib.FFParse_map_start:
			if tok != fflib.FFTok_left_bracket {
				wantedTok = fflib.FFTok_left_bracket
				goto wrongtokenerror
			}
			state = fflib.FFParse_want_key
			continue

		case fflib.FFParse_after_value:
			if tok == fflib.FFTok_comma {
				state = fflib.FFParse_want_key
			} else if tok == fflib.FFTok_right_bracket {
				goto done
			} else {
				wantedTok = fflib.FFTok_comma
				goto wrongtokenerror
			}

		case fflib.FFParse_want_key:
			// json {} ended. goto exit. woo.
			if tok == fflib.FFTok_right_bracket {
				goto done
			}
			if tok != fflib.FFTok_string {
				wantedTok = fflib.FFTok_string
				goto wrongtokenerror
			}

			kn := fs.Output.Bytes()
			if len(kn) <= 0 {
				// "" case. hrm.
				currentKey = ffj_t_UserWithIdno_such_key
				state = fflib.FFParse_want_colon
				goto mainparse
			} else {
				switch kn[0] {

				case 'i':

					if bytes.Equal(ffj_key_UserWithId_ID, kn) {
						currentKey = ffj_t_UserWithId_ID
						state = fflib.FFParse_want_colon
						goto mainparse
					}

				case 'u':

					if bytes.Equal(ffj_key_UserWithId_User, kn) {
						currentKey = ffj_t_UserWithId_User
						state = fflib.FFParse_want_colon
						goto mainparse
					}

				}

				if fflib.EqualFoldRight(ffj_key_UserWithId_User, kn) {
					currentKey = ffj_t_UserWithId_User
					state = fflib.FFParse_want_colon
					goto mainparse
				}

				if fflib.SimpleLetterEqualFold(ffj_key_UserWithId_ID, kn) {
					currentKey = ffj_t_UserWithId_ID
					state = fflib.FFParse_want_colon
					goto mainparse
				}

				currentKey = ffj_t_UserWithIdno_such_key
				state = fflib.FFParse_want_colon
				goto mainparse
			}

		case fflib.FFParse_want_colon:
			if tok != fflib.FFTok_colon {
				wantedTok = fflib.FFTok_colon
				goto wrongtokenerror
			}
			state = fflib.FFParse_want_value
			continue
		case fflib.FFParse_want_value:

			if tok == fflib.FFTok_left_brace || tok == fflib.FFTok_left_bracket || tok == fflib.FFTok_integer || tok == fflib.FFTok_double || tok == fflib.FFTok_string || tok == fflib.FFTok_bool || tok == fflib.FFTok_null {
				switch currentKey {

				case ffj_t_UserWithId_ID:
					goto handle_ID

				case ffj_t_UserWithId_User:
					goto handle_User

				case ffj_t_UserWithIdno_such_key:
					err = fs.SkipField(tok)
					if err != nil {
						return fs.WrapErr(err)
					}
					state = fflib.FFParse_after_value
					goto mainparse
				}
			} else {
				goto wantedvalue
			}
		}
	}

handle_ID:

	/* handler: uj.ID type=string kind=string quoted=false*/

	{

		{
			if tok != fflib.FFTok_string && tok != fflib.FFTok_null {
				return fs.WrapErr(fmt.Errorf("cannot unmarshal %s into Go value for string", tok))
			}
		}

		if tok == fflib.FFTok_null {

		} else {

			outBuf := fs.Output.Bytes()

			uj.ID = string(string(outBuf))

		}
	}

	state = fflib.FFParse_after_value
	goto mainparse

handle_User:

	/* handler: uj.User type=model.user kind=map quoted=false*/

	{

		{
			if tok != fflib.FFTok_left_bracket && tok != fflib.FFTok_null {
				return fs.WrapErr(fmt.Errorf("cannot unmarshal %s into Go value for user", tok))
			}
		}

		if tok == fflib.FFTok_null {
			uj.User = nil
		} else {

			uj.User = make(map[string]string, 0)

			wantVal := true

			for {

				var k string

				var tmp_uj__User string

				tok = fs.Scan()
				if tok == fflib.FFTok_error {
					goto tokerror
				}
				if tok == fflib.FFTok_right_bracket {
					break
				}

				if tok == fflib.FFTok_comma {
					if wantVal == true {
						// TODO(pquerna): this isn't an ideal error message, this handles
						// things like [,,,] as an array value.
						return fs.WrapErr(fmt.Errorf("wanted value token, but got token: %v", tok))
					}
					continue
				} else {
					wantVal = true
				}

				/* handler: k type=string kind=string quoted=false*/

				{

					{
						if tok != fflib.FFTok_string && tok != fflib.FFTok_null {
							return fs.WrapErr(fmt.Errorf("cannot unmarshal %s into Go value for string", tok))
						}
					}

					if tok == fflib.FFTok_null {

					} else {

						outBuf := fs.Output.Bytes()

						k = string(string(outBuf))

					}
				}

				// Expect ':' after key
				tok = fs.Scan()
				if tok != fflib.FFTok_colon {
					return fs.WrapErr(fmt.Errorf("wanted colon token, but got token: %v", tok))
				}

				tok = fs.Scan()
				/* handler: tmp_uj__User type=string kind=string quoted=false*/

				{

					{
						if tok != fflib.FFTok_string && tok != fflib.FFTok_null {
							return fs.WrapErr(fmt.Errorf("cannot unmarshal %s into Go value for string", tok))
						}
					}

					if tok == fflib.FFTok_null {

					} else {

						outBuf := fs.Output.Bytes()

						tmp_uj__User = string(string(outBuf))

					}
				}

				uj.User[k] = tmp_uj__User

				wantVal = false
			}

		}
	}

	state = fflib.FFParse_after_value
	goto mainparse

wantedvalue:
	return fs.WrapErr(fmt.Errorf("wanted value token, but got token: %v", tok))
wrongtokenerror:
	return fs.WrapErr(fmt.Errorf("ffjson: wanted token: %v, but got token: %v output=%s", wantedTok, tok, fs.Output.String()))
tokerror:
	if fs.BigError != nil {
		return fs.WrapErr(fs.BigError)
	}
	err = fs.Error.ToError()
	if err != nil {
		return fs.WrapErr(err)
	}
	panic("ffjson-generated: unreachable, please report bug.")
done:
	return nil
}