Appsync Repo 【720p】

AWS AppSync is a managed GraphQL service with real-time subscriptions, offline support, and data sync. This paper examines how the repository pattern can be implemented in AppSync-backed applications to abstract data sources (DynamoDB, Lambda, Aurora, HTTP) and enable testable, scalable GraphQL resolvers.

A pipeline resolver chains multiple functions together. In your repo, store each pipeline function in functions/ and the main resolver in resolvers/pipelines/. Example use case: fetch user profile → enrich with permissions → fetch posts.

Traditional REST repositories hide data access logic. In AppSync, resolvers (VTL or JavaScript) act as the repository layer. The challenge: maintaining separation of concerns when business logic sits in resolver code or Lambda functions. appsync repo

This write-up explains the architecture and benefits of a well-structured AppSync repository.

The schema.graphql file is the heart of your AppSync repo. Do not write it as one monolithic file. Use #import syntax (supported by AWS Amplify and CDK) to split it. AWS AppSync is a managed GraphQL service with

Example: types/user.graphql

type User @model 
  id: ID!
  email: String! @aws_cognito_user_pools
  profilePic: String
  posts: [Post] @hasMany

Best Practice: Store enums, inputs, and interfaces in separate files. Use schema linting in your CI pipeline (graphql-schema-linter). The schema

Here is a battle-tested folder structure for an enterprise-grade AppSync repository.

appsync-repo/
├── .github/                    # CI/CD workflows (GitHub Actions)
├── infrastructure/             # IaC (CDK, Terraform, SAM)
│   ├── stacks/
│   │   ├── api-stack.ts       # Creates AppSync API
│   │   ├── datasource-stack.ts# DynamoDB, RDS, Elasticsearch
│   │   └── auth-stack.ts      # Cognito User Pools, IAM roles
│   └── config/                 # Environment-specific variables
│       ├── dev.json
│       ├── staging.json
│       └── prod.json
├── schema/                     # GraphQL schema definition
│   ├── schema.graphql         # Root schema
│   ├── types/
│   │   ├── user.graphql
│   │   ├── product.graphql
│   │   └── order.graphql
│   └── directives/             # Custom @aws_* directives
├── resolvers/                  # Resolver logic (VTL or JS)
│   ├── functions/              # Pipeline resolver functions
│   │   ├── getUser.js
│   │   ├── createProduct.js
│   │   └── validateOrder.vtl
│   └── mappings/               # Request/response templates
│       ├── request.vtl
│       └── response.vtl
├── functions/                  # Lambda resolvers (Code)
│   ├── getOrders/
│   │   ├── index.py
│   │   └── requirements.txt
│   └── processPayment/
│       ├── index.js
│       └── package.json
├── tests/                      # Integration & unit tests
│   ├── queries/
│   │   └── getProduct.graphql
│   ├── mutations/
│   └── subscriptions/
├── scripts/                    # Utility scripts
│   ├── seed-database.js
│   └── validate-schema.sh
└── README.md                   # Onboarding & runbooks

This boilerplate supports multiple authorization modes:

Edit the authorizationConfig in infrastructure/lib/appsync-stack.ts to toggle modes.

| Pattern | Implementation | Use case | |---------|---------------|-----------| | Single-table repository | Single DynamoDB table with PK/SK + GSIs | Multi-entity domain (e.g., users, posts, comments) | | CQRS repository | Separate read (DynamoDB + GSI) and write (DynamoDB + streams) | High-scale read/write asymmetry | | Event-driven repository | Save to DynamoDB + publish to EventBridge | Integration with event sourcing | | Offline repository | AWSAppSyncClient + local store (SQLite/IndexedDB) | Mobile/web with sync conflict resolution |

appsync repo