fwojciec

func newAgentByAuthorID(ctx context.Context, repo pg.Repository) *AgentLoader {
	return NewAgentLoader(AgentLoaderConfig{
		MaxBatch: 100,
		Wait:     5 * time.Millisecond,
		Fetch: func(authorIDs []int64) ([]*pg.Agent, []error) {
			// db query
			res, err := repo.ListAgentsByAuthorIDs(ctx, authorIDs)
			if err != nil {
				return nil, []error{err}
			}

fwojciec

// Loaders holds references to the individual dataloaders.
type Loaders struct {
	AgentByAuthorID *AgentLoader
}

fwojciec

// AgentLoaderConfig captures the config to create a new AgentLoader
type AgentLoaderConfig struct {
	// Fetch is a method that provides the data for the loader
	Fetch func(keys []int64) ([]*pg.Agent, []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

fwojciec

package dataloaders

//go:generate go run github.com/vektah/dataloaden AgentLoader int64 *github.com/[username]/gqlgen-sqlc-example/pg.Agent

fwojciec

package main

import (
	"fmt"
	"net/http"
	"os"

	"github.com/[username]/gqlgen-sqlc-example/dataloaders" // update the username
	"github.com/[username]/gqlgen-sqlc-example/gqlgen"      // update the username
	"github.com/[username]/gqlgen-sqlc-example/pg"          // update the username

fwojciec

// NewHandler returns a new graphql endpoint handler.
func NewHandler(repo pg.Repository, dl dataloaders.Retriever) http.Handler {
	return handler.GraphQL(NewExecutableSchema(Config{
		Resolvers: &Resolver{
			Repository:  repo,
			DataLoaders: dl,
		},
	}))
}

fwojciec

// Resolver connects individual resolvers with the datalayer.
type Resolver struct {
	Repository  pg.Repository
	DataLoaders dataloaders.Retriever
}

fwojciec

// Retriever retrieves dataloaders from the request context.
type Retriever interface {
	Retrieve(context.Context) *Loaders
}

type retriever struct {
	key contextKey
}

func (r *retriever) Retrieve(ctx context.Context) *Loaders {

fwojciec

package dataloaders

import (
	"context"
	"net/http"

	"github.com/[username]/gqlgen-sqlc-example/pg" // update the username
)

// Middleware stores Loaders as a request-scoped context value.

fwojciec

package dataloaders

import (
	"context"

	"github.com/[username]/gqlgen-sqlc-example/pg" // update the username
)

type contextKey string