INTERNAL USE ONLY
This package contains the AWS Amplify DataStore category and is intended for internal use only. To integrate Amplify into your app, please use aws-amplify.
AWS Amplify DataStore Docs
Amplify DataStore provides a programming model for leveraging shared and distributed data without writing additional code for offline and online scenarios, which makes working with distributed, cross-user data just as simple as working with local-only data.
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@aws-amplify/datastore | | | |
š Note For Contributers: š
Please update these docs any time you find something that is incorrect or lacking. In particular, if a line in the docs prompts a question, take a moment to figure out the answer, then update the docs with the necessary detail.
Getting Started
Before you start reading through these docs, take a moment to understand how DataStore works at a high level. Additionally, we recommend first reading through docs.amplify.aws. The purpose of these docs is to dive deep into the codebase itself and understand the inner workings of DataStore for the purpose of contributing. Understanding these docs is not necessary for using DataStore. Lastly, before reading, take a look at the diagrams below.
Docs
Diagrams
Note: relationships with dotted lines are explained more in a separate diagram.
How the DataStore API and Storage Engine Interact
flowchart TD
%% API and Storage
api[[DS API]]-- observe -->storage{Storage Engine}
storage-- next -->adapter[[Adapter]]
adapter-->db[[Local DB]]
db-->api
sync[[Sync Engine*]]-.-storage
sync-.-appSync[(AppSync)]
How the Sync Engine Observes Changes in Storage and AppSync
Note: All green nodes belong to the Sync Engine.
* Merger first checks outbox
** Outbox sends outgoing messages to AppSync
flowchart TD
subgraph SyncEngine
index{index.ts}-- observe -->reach[Core reachability]
subgraph processors
mp[Mutation Processor]
sp[Subscription Processor]
syp[Sync Processor]
end
reach--next-->mp[Mutation Processor]
reach--next-->sp[Subscription Processor]
reach--next-->syp[Sync Processor]
subgraph outbox / merger
outbox[Outbox]
merger[Merger]
outbox---merger
end
end
api[DS API]-.->storage
mp-- 1. observe -->storage{Storage Engine}
storage-- 2. next -->merger[merger*]-- next -->storage
sp-- observe -->appsync[(AppSync)]
appsync-- next -->sp
syp---appsync
mp-->outbox[outbox**]
appsync<--->outbox
%% styling
classDef syncEngineClass fill:#8FB,stroke:#333,stroke-width:4px,color:#333;
class index,mp,sp,syp,merger,outbox syncEngineClass;
Project Structure
amplify-js/packages/datastore/src
āāā authModeStrategies
ā āāā defaultAuthStraegy.ts
ā āāā index.ts
ā āāā multiAuthStrategy.ts
āāā datastore
ā āāā datastore.ts # Entry point for DataStore
āāā predicates
ā āāā index.ts
ā āāā sort.ts
āāā ssr
āāā storage # Storage Engine
ā āāā adapter # Platform-specific Storage Adapters
ā āāā getDefaultAdapter
ā āāā AsyncStorageAdapter.ts
ā āāā AsyncStorageDatabase.ts
ā āāā index.ts
ā āāā IndexedDBAdapter.ts
ā āāā InMemoryStore.native.ts
ā āāā InMemoryStore.ts
ā āāā storage.ts # Entry point for Storage
āāā sync # Sync Engine
ā āāā dataStoreReachability
ā āāā index.native.ts
ā āāā index.ts
ā āāā processors # Sync Engine Processors
ā āāā mutation.ts
ā āāā subscription.ts
ā āāā sync.ts
ā āāā datastoreConnectivity.ts # Subscribe to reachability monitor
ā āāā index.ts # Entry point for Sync Engine
ā āāā merger.ts # doc
ā āāā outbox.ts # doc
Other Resources: