dataloader

Documentation

Overview

Package dataloader provides efficient batching and caching mechanisms for database operations. This implements the DataLoader pattern to solve N+1 query problems commonly found in GraphQL and REST API implementations, with specific optimizations for DynamoDB access patterns.

Index

• type BatchFunc
• type Config
  • func DefaultConfig() Config
• type DataLoader
  • func NewDataLoader[K comparable, V any](batchFn BatchFunc[K, V], cfg Config, logger *zap.Logger) *DataLoader[K, V]
  • func (dl *DataLoader[K, V]) Clear(key K)
  • func (dl *DataLoader[K, V]) ClearAll()
  • func (dl *DataLoader[K, V]) GetStats() LoaderStats
  • func (dl *DataLoader[K, V]) Load(ctx context.Context, key K) (V, error)
  • func (dl *DataLoader[K, V]) LoadMany(ctx context.Context, keys []K) ([]V, []error)
  • func (dl *DataLoader[K, V]) Prime(key K, value V, err error)
• type LoaderStats

Types

type BatchFunc

type BatchFunc[K comparable, V any] func(context.Context, []K) ([]V, []error)

BatchFunc defines the signature for batch loading functions

type Config

type Config struct {
	Wait        time.Duration // How long to wait before executing a batch (default: 1ms)
	MaxBatch    int           // Maximum batch size (default: 100)
	Cache       bool          // Enable caching (default: true)
	CacheExpiry time.Duration // Cache expiry time (default: 5 minutes)
}

Config holds configuration for DataLoader

func DefaultConfig

func DefaultConfig() Config

DefaultConfig returns default DataLoader configuration

type DataLoader

type DataLoader[K comparable, V any] struct {
	// contains filtered or unexported fields
}

DataLoader provides batching and caching for database operations

func NewDataLoader

func NewDataLoader[K comparable, V any](batchFn BatchFunc[K, V], cfg Config, logger *zap.Logger) *DataLoader[K, V]

NewDataLoader creates a new DataLoader with the given batch function

func (*DataLoader[K, V]) Clear

func (dl *DataLoader[K, V]) Clear(key K)

Clear removes a key from the cache

func (*DataLoader[K, V]) ClearAll

func (dl *DataLoader[K, V]) ClearAll()

ClearAll clears the entire cache

func (*DataLoader[K, V]) GetStats

func (dl *DataLoader[K, V]) GetStats() LoaderStats

GetStats returns loader statistics

func (*DataLoader[K, V]) Load

func (dl *DataLoader[K, V]) Load(ctx context.Context, key K) (V, error)

Load loads a single value by key, batching with other concurrent requests

func (*DataLoader[K, V]) LoadMany

func (dl *DataLoader[K, V]) LoadMany(ctx context.Context, keys []K) ([]V, []error)

LoadMany loads multiple values by keys, batching efficiently

func (*DataLoader[K, V]) Prime

func (dl *DataLoader[K, V]) Prime(key K, value V, err error)

Prime adds a value to the cache without loading

type LoaderStats

type LoaderStats struct {
	Hits      int64 `json:"hits"`
	Misses    int64 `json:"misses"`
	Batches   int64 `json:"batches"`
	Errors    int64 `json:"errors"`
	CacheSize int   `json:"cache_size"`
}

LoaderStats holds statistics about loader performance