EnergyWeb Origin
Origin-Backend-App
**Origin-Backend-App** package provides is a runner for a nest.js application that consist of **Origin-Backend** and **Exchange** packages.
## Development
Exchange project is currently not meant to be run as a separate nest application. In order to run exchange project please refer to https://github.com/energywebfoundation/origin/tree/master/packages/origin-backend-app
`yarn start` to start the origin backend and exchange as one application Note: this will not run the migrations for origin-backend and exchange.
Default TypeOrm configuration requires running PostgreSQL database. The detailed config with .env parameters is:
```
DB_HOST - default 'localhost'
DB_PORT - default 5432
DB_USERNAME - default 'postgres',
DB_PASSWORD - default 'postgres',
DB_DATABASE - default 'origin',
```
or
```
DATABASE_URL - postgres://{user}:{password}@{host}:{port}/{database}
```
Other configuration variables
```
PORT:
BACKEND_PORT:
BACKEND_URL:
BLOCKCHAIN_EXPLORER_URL:
DEPLOY_KEY:
EMAIL_FROM:
EMAIL_REPLY_TO:
ENERGY_API_BASE_URL:
EXCHANGE_ACCOUNT_DEPLOYER_PRIV:
EXCHANGE_WALLET_PRIV:
EXCHANGE_WALLET_PUB:
ISSUER_ID:
JWT_EXPIRY_TIME:
JWT_SECRET:
MANDRILL_API_KEY:
REGISTRATION_MESSAGE_TO_SIGN:
UI_BASE_URL:
WEB3:
MARKET_UTC_OFFSET:
```
### PostgreSQL installation using Docker
```
docker pull postgres
docker run --name origin-postgres -e POSTGRES_PASSWORD=postgres -d -p 5432:5432 postgres
```
#### pgAdmin
```
docker pull dpage/pgadmin4
docker run -p 80:80 \
-e 'PGADMIN_DEFAULT_EMAIL=user@domain.com' \
-e 'PGADMIN_DEFAULT_PASSWORD=SuperSecret' \
-d dpage/pgadmin4
```
### Swagger
Swagger endpoint can be found at
`http://localhost:3033/api`
### Custom event handlers
It's possible to handle events emitted by `@energyweb/exchange` in the `@energyweb/origin-backend-app` project. This feature allows 3rd party developers to implement custom event handling logic, additional to existing core event handlers.
Currently supported event is `BulkTradeExecutedEvent` which is emitted whenever new trade in the matching engine occurs.
In order to register custom event handler for this event please follow these steps:
1. Create custom event handler code
```
import { BulkTradeExecutedEvent } from '@energyweb/exchange';
import { Logger } from '@nestjs/common';
import { EventsHandler, IEventHandler } from '@nestjs/cqrs';
@EventsHandler(BulkTradeExecutedEvent)
export class NewTradeExecutedEventHandler implements IEventHandler {
private readonly logger = new Logger(NewTradeExecutedEventHandler.name);
async handle(event: BulkTradeExecutedEvent) {
this.logger.debug(`Received trade executed events ${JSON.stringify(event)}`);
}
}
```
Note: This follows the recipe created by Nest.js team which is documented here https://docs.nestjs.com/recipes/cqrs
2. Register your event handler as provider in `origin-app.module.ts`
```
@Module({})
export class OriginAppModule {
static register(smartMeterReadingsAdapter: ISmartMeterReadingsAdapter): DynamicModule {
return {
module: OriginAppModule,
imports: [
OriginAppTypeOrmModule(),
OriginBackendModule.register(smartMeterReadingsAdapter),
ExchangeModule
],
providers: [NewTradeExecutedEventHandler] // <-- add your event handler here
};
}
}
```
Note: Due to a way in which Nest.js is handling DI, your custom handler class name has to be unique, this means you should not use name taken by core event handler **TradeExecutedEventHandler**