go-jsonschema is a tool to generate Go data types from JSON Schema definitions.
This tool generates Go data types and structs that corresponds to definitions in the schema, along with unmarshalling code that validates the input JSON according to the schema's validation rules.
Download: Get a release here.
Install from source: To install with Go 1.22+:
go get github.com/atombender/go-jsonschema/...
go install github.com/atombender/go-jsonschema@latest
brew tap omissis/go-jsonschema
brew install go-jsonschema
This project makes use of go workspaces in order to ease testing of the generated code during development while keeping the codebase as tidy and maintainable as possible. It's an unusual choice, but it allows to not only test the code-generation logic, but also the generated code itself.
At its most basic:
go-jsonschema -p main schema.json
This will write a Go source file to standard output, declared under the package main
.
You can generate code for multiple schemas in one run, optionally writing to different files inside different packages:
$ go-jsonschema \
--schema-package=https://example.com/schema1=github.com/myuser/myproject \
--schema-output=https://example.com/schema1=schema1.go \
--schema-package=https://example.com/schema2=github.com/myuser/myproject/stuff \
--schema-output=https://example.com/schema2=stuff/schema2.go \
schema1.json schema2.json
This will create schema1.go
(declared as package myproject
) and stuff/schema2.go
(declared as package stuff
).
If schema1.json
refers to schema2.json
or viceversa, the two Go files will import the other depended-on package.
Note the flag format:
--schema-package=https://example.com/schema1=github.com/myuser/myproject \
^ ^
| |
schema $id full import URL
In a few cases, special types are used to help with serializing/deserializing data frrom JSON. Namely a custom types is provided for the following semantic types:
SerializableDate
SerializableTime
These types are needed because there is no native type provided by Go which properly handles them.
While not finished, go-jsonschema can be used today. Aside from some minor features, only specific validations remain to be fully implemented.
null
boolean
object
array
number
json.Number
string
#/$defs/someName
#/$defs/someName/$defs/someOtherName
myschema.json#/$defs/someName
myschema.json#/$defs/someName/$defs/someOtherName
description
default
(only for struct fields)readOnly
writeOnly
title
examples
enum
type
(single)type
(multiple; note: partial support, limited validation)const
multipleOf
maximum
exclusiveMaximum
minimum
exclusiveMinimum
maxLength
minLength
pattern
items
maxItems
minItems
uniqueItems
additionalItems
contains
required
properties
patternProperties
dependencies
propertyNames
maxProperties
minProperties
if
then
else
allOf
anyOf
oneOf
not
MIT license. See LICENSE
file.