dataloader

README

dataloader

This example uses dataloaden to avoiding n+1 queries.

There is also nicksrandall/dataloader if you wanted to avoid doing more codegeneration.

Documentation

Index

• func LoaderMiddleware(next http.Handler) http.Handler
• func NewExecutableSchema(cfg Config) graphql.ExecutableSchema
• type Address
• type AddressLoader
  • func NewAddressLoader(config AddressLoaderConfig) *AddressLoader
  • func (l *AddressLoader) Clear(key int)
  • func (l *AddressLoader) Load(key int) (*Address, error)
  • func (l *AddressLoader) LoadAll(keys []int) ([]*Address, []error)
  • func (l *AddressLoader) LoadThunk(key int) func() (*Address, error)
  • func (l *AddressLoader) Prime(key int, value *Address) bool
• type AddressLoaderConfig
• type ComplexityRoot
• type Config
• type Customer
• type CustomerResolver
• type DirectiveRoot
• type Item
• type ItemSliceLoader
  • func NewItemSliceLoader(config ItemSliceLoaderConfig) *ItemSliceLoader
  • func (l *ItemSliceLoader) Clear(key int)
  • func (l *ItemSliceLoader) Load(key int) ([]Item, error)
  • func (l *ItemSliceLoader) LoadAll(keys []int) ([][]Item, []error)
  • func (l *ItemSliceLoader) LoadThunk(key int) func() ([]Item, error)
  • func (l *ItemSliceLoader) Prime(key int, value []Item) bool
• type ItemSliceLoaderConfig
• type Order
• type OrderResolver
• type OrderSliceLoader
  • func NewOrderSliceLoader(config OrderSliceLoaderConfig) *OrderSliceLoader
  • func (l *OrderSliceLoader) Clear(key int)
  • func (l *OrderSliceLoader) Load(key int) ([]Order, error)
  • func (l *OrderSliceLoader) LoadAll(keys []int) ([][]Order, []error)
  • func (l *OrderSliceLoader) LoadThunk(key int) func() ([]Order, error)
  • func (l *OrderSliceLoader) Prime(key int, value []Order) bool
• type OrderSliceLoaderConfig
• type QueryResolver
• type Resolver
  • func (r *Resolver) Customer() CustomerResolver
  • func (r *Resolver) Order() OrderResolver
  • func (r *Resolver) Query() QueryResolver
• type ResolverRoot

Functions

func LoaderMiddleware

func LoaderMiddleware(next http.Handler) http.Handler

func NewExecutableSchema

func NewExecutableSchema(cfg Config) graphql.ExecutableSchema

NewExecutableSchema creates an ExecutableSchema from the ResolverRoot interface.

Types

type Address

type Address struct {
	ID      int    `json:"id"`
	Street  string `json:"street"`
	Country string `json:"country"`
}

type AddressLoader

type AddressLoader struct {
	// contains filtered or unexported fields
}

AddressLoader batches and caches requests

func NewAddressLoader

func NewAddressLoader(config AddressLoaderConfig) *AddressLoader

NewAddressLoader creates a new AddressLoader given a fetch, wait, and maxBatch

func (*AddressLoader) Clear

func (l *AddressLoader) Clear(key int)

Clear the value at key from the cache, if it exists

func (*AddressLoader) Load

func (l *AddressLoader) Load(key int) (*Address, error)

Load a address by key, batching and caching will be applied automatically

func (*AddressLoader) LoadAll

func (l *AddressLoader) LoadAll(keys []int) ([]*Address, []error)

LoadAll fetches many keys at once. It will be broken into appropriate sized sub batches depending on how the loader is configured

func (*AddressLoader) LoadThunk

func (l *AddressLoader) LoadThunk(key int) func() (*Address, error)

LoadThunk returns a function that when called will block waiting for a address. This method should be used if you want one goroutine to make requests to many different data loaders without blocking until the thunk is called.

func (*AddressLoader) Prime

func (l *AddressLoader) Prime(key int, value *Address) bool

Prime the cache with the provided key and value. If the key already exists, no change is made and false is returned. (To forcefully prime the cache, clear the key first with loader.clear(key).prime(key, value).)

type AddressLoaderConfig

type AddressLoaderConfig struct {
	// Fetch is a method that provides the data for the loader
	Fetch func(keys []int) ([]*Address, []error)

	// Wait is how long wait before sending a batch
	Wait time.Duration

	// MaxBatch will limit the maximum number of keys to send in one batch, 0 = not limit
	MaxBatch int
}

AddressLoaderConfig captures the config to create a new AddressLoader

type ComplexityRoot

type ComplexityRoot struct {
	Address struct {
		ID      func(childComplexity int) int
		Street  func(childComplexity int) int
		Country func(childComplexity int) int
	}

	Customer struct {
		ID      func(childComplexity int) int
		Name    func(childComplexity int) int
		Address func(childComplexity int) int
		Orders  func(childComplexity int) int
	}

	Item struct {
		Name func(childComplexity int) int
	}

	Order struct {
		ID     func(childComplexity int) int
		Date   func(childComplexity int) int
		Amount func(childComplexity int) int
		Items  func(childComplexity int) int
	}

	Query struct {
		Customers func(childComplexity int) int
		Torture1d func(childComplexity int, customerIds []int) int
		Torture2d func(childComplexity int, customerIds [][]int) int
	}
}

type Config

type Config struct {
	Resolvers  ResolverRoot
	Directives DirectiveRoot
	Complexity ComplexityRoot
}

type Customer

type Customer struct {
	ID        int    `json:"id"`
	Name      string `json:"name"`
	AddressID int
}

type CustomerResolver

type CustomerResolver interface {
	Address(ctx context.Context, obj *Customer) (*Address, error)
	Orders(ctx context.Context, obj *Customer) ([]Order, error)
}

type DirectiveRoot

type DirectiveRoot struct {
}

type Item

type Item struct {
	Name string `json:"name"`
}

type ItemSliceLoader

type ItemSliceLoader struct {
	// contains filtered or unexported fields
}

ItemSliceLoader batches and caches requests

func NewItemSliceLoader

func NewItemSliceLoader(config ItemSliceLoaderConfig) *ItemSliceLoader

NewItemSliceLoader creates a new ItemSliceLoader given a fetch, wait, and maxBatch

func (*ItemSliceLoader) Clear

func (l *ItemSliceLoader) Clear(key int)

Clear the value at key from the cache, if it exists

func (*ItemSliceLoader) Load

func (l *ItemSliceLoader) Load(key int) ([]Item, error)

Load a item by key, batching and caching will be applied automatically

func (*ItemSliceLoader) LoadAll

func (l *ItemSliceLoader) LoadAll(keys []int) ([][]Item, []error)

LoadAll fetches many keys at once. It will be broken into appropriate sized sub batches depending on how the loader is configured

func (*ItemSliceLoader) LoadThunk

func (l *ItemSliceLoader) LoadThunk(key int) func() ([]Item, error)

LoadThunk returns a function that when called will block waiting for a item. This method should be used if you want one goroutine to make requests to many different data loaders without blocking until the thunk is called.

func (*ItemSliceLoader) Prime

func (l *ItemSliceLoader) Prime(key int, value []Item) bool

Prime the cache with the provided key and value. If the key already exists, no change is made and false is returned. (To forcefully prime the cache, clear the key first with loader.clear(key).prime(key, value).)

type ItemSliceLoaderConfig

type ItemSliceLoaderConfig struct {
	// Fetch is a method that provides the data for the loader
	Fetch func(keys []int) ([][]Item, []error)

	// Wait is how long wait before sending a batch
	Wait time.Duration

	// MaxBatch will limit the maximum number of keys to send in one batch, 0 = not limit
	MaxBatch int
}

ItemSliceLoaderConfig captures the config to create a new ItemSliceLoader

type Order

type Order struct {
	ID     int       `json:"id"`
	Date   time.Time `json:"date"`
	Amount float64   `json:"amount"`
}

type OrderResolver

type OrderResolver interface {
	Items(ctx context.Context, obj *Order) ([]Item, error)
}

type OrderSliceLoader

type OrderSliceLoader struct {
	// contains filtered or unexported fields
}

OrderSliceLoader batches and caches requests

func NewOrderSliceLoader

func NewOrderSliceLoader(config OrderSliceLoaderConfig) *OrderSliceLoader

NewOrderSliceLoader creates a new OrderSliceLoader given a fetch, wait, and maxBatch

func (*OrderSliceLoader) Clear

func (l *OrderSliceLoader) Clear(key int)

Clear the value at key from the cache, if it exists

func (*OrderSliceLoader) Load

func (l *OrderSliceLoader) Load(key int) ([]Order, error)

Load a order by key, batching and caching will be applied automatically

func (*OrderSliceLoader) LoadAll

func (l *OrderSliceLoader) LoadAll(keys []int) ([][]Order, []error)

LoadAll fetches many keys at once. It will be broken into appropriate sized sub batches depending on how the loader is configured

func (*OrderSliceLoader) LoadThunk

func (l *OrderSliceLoader) LoadThunk(key int) func() ([]Order, error)

LoadThunk returns a function that when called will block waiting for a order. This method should be used if you want one goroutine to make requests to many different data loaders without blocking until the thunk is called.

func (*OrderSliceLoader) Prime

func (l *OrderSliceLoader) Prime(key int, value []Order) bool

Prime the cache with the provided key and value. If the key already exists, no change is made and false is returned. (To forcefully prime the cache, clear the key first with loader.clear(key).prime(key, value).)

type OrderSliceLoaderConfig

type OrderSliceLoaderConfig struct {
	// Fetch is a method that provides the data for the loader
	Fetch func(keys []int) ([][]Order, []error)

	// Wait is how long wait before sending a batch
	Wait time.Duration

	// MaxBatch will limit the maximum number of keys to send in one batch, 0 = not limit
	MaxBatch int
}

OrderSliceLoaderConfig captures the config to create a new OrderSliceLoader

type QueryResolver

type QueryResolver interface {
	Customers(ctx context.Context) ([]Customer, error)
	Torture1d(ctx context.Context, customerIds []int) ([]Customer, error)
	Torture2d(ctx context.Context, customerIds [][]int) ([][]Customer, error)
}

type Resolver

type Resolver struct{}

func (*Resolver) Customer

func (r *Resolver) Customer() CustomerResolver

func (*Resolver) Order

func (r *Resolver) Order() OrderResolver

func (*Resolver) Query

func (r *Resolver) Query() QueryResolver

type ResolverRoot

type ResolverRoot interface {
	Customer() CustomerResolver
	Order() OrderResolver
	Query() QueryResolver
}