Glossary¶
- Apollo Graphql
typeDefs: also known as graphql schema, see Apollo documentation
resolvers: also known as graphql resolver, see Apollo documentation
- Client Application Developer
- He develops the client application to consume the data services from Federated Gateway.
- Command Handler
- A command handler receives command from the aggregate.
- Commit
- Commit is data representation for each writing transaction to Hyperledger Fabric. One commit may carry one, or an array of (business) events.
- Domain Model
- This is a broader definition than the conventional meaning of DDD. Domain models in fabric-es includes (1) conventional DDD domain model, (2) Redis models and indexing definition, and Apollo endpoint definition. For example, typeDefs, resolvers, events, models, reducer, indexDefinition.
- Entity
- In our current design, each federated service represents one aggregate; and in turn representing one entity; are 1:1:1 mapping. Both aggregate and entity refers the same meaning as entity model. For simplicity, entity are aggregate are interchangeable in our context.
- Federated Gateway
- also known as, Apollo Federated API Gateway; giving Domain-Driven API endpoint to compose data graphs from underlying domain service. Also, it may give /healthz, which performs health check monitoring, for underlying service. This gateway does NOT replace API gateway of client application. The client application is free to choose any type of API gateway technology.
- Federated Service
There are threee types, (1) administrative service, (2) domain service, and (3) remote-data service.
Domain service exposes via Apollo federated service. The Gateway developer models the data graph for for one Entity.
- Gateway Developer
- He develops the federated API gateway and underlying federated microservice.
- Identity Wallet
- Servers-side digital wallet, carrying list of X.509 ecert. This is generated during Fabric-CA user enrollment process. It is now using Fabric’s file wallet, residing under the Federated API Gateway. All transaction written to Fabric network requires corresponding X.509 ecert obtained from this wallet.
- Model-free Chaincode
- Chaincode implementation which does not carry any domain model / data model inforrmation. That means, changes in model does not require code refactoring in chaincode.
- Network Operator
- He runs (1) Org0 - orderers; (2) Org1 - administratrive peer-node. Optionally, as a value-added service, he may also run peer-nodes from other organizations.
- Private Repository
- Abstraction of Hyperledger Fabric private data
- Query Database
- Abstraction of DB operations, e.g. merge commit, merge entity
- Query Handler
- Query handler processes query request, returning output model of entity.
- RedisRepository
- Abstraction of Redis operations, e.g. GET, SET, HGETALL, FT.SEARCH, etc.
- Redisearch - modelling
Index Definition defines indexing fields, and indexing parameters per entity.
InRedis Model: model representation in the Redisearch. Currently, hash table is the only supported format.
Input Model: model representation, before processing of pre-Selector.
Output Model: model representation, after processing of post-Selector.
Pre-Selector: Selector function transforms input model to inRedis model.
Post-Selector: Selector function transforms inRedis model to output model.
- Repository
- Abstraction of Hyperledger Fabric on-chain data per entity
- Repository Pattern
- Repository provides abstraction of data, so that applcation can work with simple abstraction. See Repository Pattern.