![Go Report Card](https://goreportcard.com/badge/github.com/VerTox/graphql-codegen-go)
graphql-codegen-go
Generate Go structs from your GraphQL schema.
This code generator helps you derive Go structures directly from GraphQL schema. The schema
can be located either locally or can be fetched from GIT repository.
Install it using go get
:
$ go get -u github.com/VerTox/graphql-codegen-go
Quick start
Simply, define the GQL schema
type Person {
name: String!
age: Int!
weight: Int
likes: [String]
donts: [String!]
}
and save it, e.g. in schema.gql
file. Then run the code generator
$ graphql-codegen-go -schemas schema.gql -packageName pkg -out models.go
As a result, you will get a models.go
file with the following Go code
// Code generated by go generate; DO NOT EDIT.
// This file was generated from GraphQL schema schema.gql
package pkg
type Person struct {
Name string `json:"name"`
Age int64 `json:"age"`
Weight *int64 `json:"weight"`
Likes []*string `json:"likes"`
Donts []string `json:"donts"`
}
Notice that not required (weight
) fields are converted to the pointers. The packageName
option is optional. The generator
will try to derive the package name from the current running path of the code, or if run by go:generate
from $GOPACKAGE
env variable.
GIT
The schema does not have to be located locally. The program supports also Git repositories.
Let's assume that you the schema.gql
file is placed in github.com/orange/repo1
repository, inside a deployment
directory.
Then, to create the structures you can run the generator as follows
$ graphql-codegen-go -schemas https://github.com/orange/repo1.git/deployment/schema.gql -packageName pkg -out models.go
or via ssh
$ graphql-codegen-go -schemas git@github.com:orange/repo1.git/deployment/schema.gql -packageName pkg -out models.go
By default, the schema is pulled from the HEAD
. To point a specific commit, you can place a commit hash after the file name, e.g.,
$ graphql-codegen-go -schemas git@github.com:orange/repo1.git/deployment/schema.gql#a56351vc -packageName pkg -out models.go
Moreover, you can also point the specific branch or tag by using @
sign
$ graphql-codegen-go -schemas git@github.com:orange/repo1.git/deployment/schema.gql@branch -packageName pkg -out models.go
or
$ graphql-codegen-go -schemas git@github.com:orange/repo1.git/deployment/schema.gql@tag1 -packageName pkg -out models.go
Entities
By default generator will output structures for all of the entities found in the schema. To output only a subset of structures
you can use -entities
option.
For example
$ graphql-codegen-go -schemas schema.gql -packageName pkg -out models.go -entities Person
will create file models.go
only with a single structure Person
, and all related dependent structures and enums.
YAML Config
Instead of command line parameters, the generator supports also a config file (-config
). The example of the file can be found in examples/config/config.yml
.
The structure of the YAML file is
schema: A list of schema files (it will be combined into one schema before parsing)
generates: A key-value map, where key is the name of the output Go file
<output-file>:
config:
packageName: A package name
entities: A list of entities to be included into the output Go file
Example
schema:
- ./schema.graphql
- ./types.graphql
- https://github.com/VerTox/sc.git/schema1.gql
generates:
internal/models.go:
config:
packageName: internal
entities:
- User
- Person
internal/abc/models.go:
config:
packageName: abc
entities:
- Action
After execution of the above config you will find two .go
files (internal/models.go
and internal/abc/models.go
);
the first will contain structures User
and Person
, and the second Action
.
The GQL schema will be read from two local files, from GIT repository.
go:generate
The generator can work perfectly fine with the go:generate
directive. The examples of how to include it can be found in examples/
directory.
Union
The union type is supported in the following way. Let's consider a schema
type Et {
value: String
}
type Pt {
label: String!
}
union Ett = Et | Pt
type Entity {
id: String!
etpt: Ett
}
The union type Ett
is converted into a Go struct Ett
type Et struct {
Value *string `json:"value"`
}
type Pt struct {
Label string `json:"label"`
}
type Ett struct {
TypeName string `json:"__typeName"`
Et
Pt
}
type Entity struct {
Id string `json:"id"`
Etpt *Ett `json:"etpt"`
}