mockfactory

Mockfactory is a simple CLI util to generate mock and test data from your Golang structs.

Installation

Via go install:

go install github.com/maksemen2/mockfactory/cmd/mockfactory@latest

Building from source:

git clone https://github.com/maksemen2/mockfactory.git
cd mockfactory
make

Features

• Realistic random data generation for your structs fields
• Flexible data export:
  • File per struct
  • All data in one file
  • Custom file name templates
• Field ignore strategies:
  • Ignore untagged fields
  • Ignore fields with "ignore" tag
  • Generate every field
• Out-of-box Go primitives support:
  • Integer (int, uint etc.)
  • Floating (float32, float64)
  • Strings
  • Time

Examples

Base

// test.go
package test

import "time"

type User struct {
	ID        int       `mock:"min=1000;max=9999"`
	Name      string    `mock:"prefix=user"`
	CreatedAt time.Time `mock:"range=past"`
	Balance   float32
}

mockfactory --input ./test.go --count 2 --template "mock_{struct}_{count}" --output result

Output in result/mock_User_2.json file:

[
 {
  "Balance": -3.511347e+37,
  "CreatedAt": "2025-03-23T23:34:48.9917166+03:00",
  "ID": 9499,
  "Name": "userkgmRybLT"
 },
 {
  "Balance": 2.4197568e+38,
  "CreatedAt": "2025-03-23T23:34:48.9932214+03:00",
  "ID": 1607,
  "Name": "usermf6RYzcE"
 }
]

Configuration

CLI arguments

Flag	Description	Default
--count	Number of objects to generate per struct	1
--format	Output format	json
--ignore	Ignore strategy: untagged or with-tag or all or none	all
-i or --input	Path to input Go file	-
--log-level	Log level: debug or info or warn or error	error
-o or --output	Output path	.
--seed	Random seed	time.Now().UnixNano()
--strategy	Output strategy: per-struct or single-file	per-struct
--structs	Comma-separated list of struct names	-
--template	File name template (e.g. {struct}_{count}.json)	-

Mock tags

float(32/64)

Tag	Description	Default
min	Minimal number	-math.MaxFloat32 / -1e307
max	Maximal number	math.MaxFloat32 / 1e307

int(-/8/16/32/64)

Tag	Description	Default
min	Minimal number	math.MinInt(-/8/16/32/64)
max	Maximal number	math.MaxInt(-/8/16/32/64)

uint(-/8/16/32/64)

Tag	Description	Default
min	Minimal number	0
max	Maximal number	math.MaxUint(-/8/16/32/64)

string

Tag	Description	Default
len	Length of result string (not including prefix and suffix length)	8
prefix	Prefix of result string	""
suffix	Suffix of result string	""

time.Time

Tag	Description	Default
range	Range of the time. Can be "past" or "future"	""

github.com/google/uuid.UUID

There are no tags currently available :)

TBD

• Add nested structures support
• Add more interesting tags for data types (m.b. something like "email" tag for string for email to be created)
• Add convenient API to register your own writers and generators for arbitrary data types