Import LB3 DataSources to a LB4 Project

[nabdelgadir]

Related to #3946.

Currently, users have to manually move their datasources from LB3 to LB4 using the steps defined in #4343. In order to automate this process, create a CLI command that will move the datasources from a mounted LB3 application to the LB4 project.

Since LB3 datasources are compatible with LB4, the same datasource configuration should be used when it's moved.

Example

Given this file in the mounted LB3 application:

lb3app/server/datasources.json

{
  "db": {
    "name": "db",
    "connector": "memory"
  },
  "mysqlDs": {
    "name": "mysqlDs",
    "connector": "mysql",
    "host": "demo.strongloop.com",
    "port": 3306,
    "database": "getting_started",
    "username": "demo",
    "password": "L00pBack"
  }
}

Create the following in the LB4 project:

src/datasources/db.datasource.config.json

{
  "name": "db",
  "connector": "memory"
}

src/datasources/db.datasource.ts

import {inject} from '@loopback/core';
import {juggler} from '@loopback/repository';
import config from './db.datasource.config.json';

export class DbDataSource extends juggler.DataSource {
  static dataSourceName = 'db';

  constructor(
    @inject('datasources.config.db', {optional: true})
    dsConfig: object = config,
  ) {
    super(dsConfig);
  }
}

src/datasources/mysqlds.datasource.config.json

{
   "name": "mysqlDs",
    "connector": "mysql",
    "host": "demo.strongloop.com",
    "port": 3306,
    "database": "getting_started",
    "username": "demo",
    "password": "L00pBack"
}

src/datasources/mysqlds.datasource.ts

import {inject} from '@loopback/core';
import {juggler} from '@loopback/repository';
import config from './mysqlds.datasource.config.json';

export class MysqlDsDataSource extends juggler.DataSource {
  static dataSourceName = 'mysqlDs';

  constructor(
    @inject('datasources.config.mysqlDs', {optional: true})
    dsConfig: object = config,
  ) {
    super(dsConfig);
  }
}

Acceptance criteria

• Create a CLI flag lb4 import-lb3-datasources that will take in a path to a file e.g. lb4 import-lb3-datasources lb3app/servers/datasources.json and migrate all datasources similar to the example above
  • Remember to export the datasources from src/datasources/index.ts
• Update documentation in Migrating datasources, and include limitations if any exist

[nabdelgadir]

Note that since #5000 has landed, please follow the new format for the datasource definition.

[stale]

This issue has been marked stale because it has not seen activity within six months. If you believe this to be in error, please contact one of the code owners, listed in the CODEOWNERS file at the top-level of this repository. This issue will be closed within 30 days of being stale.

[stale]

This issue has been marked stale because it has not seen activity within six months. If you believe this to be in error, please contact one of the code owners, listed in the CODEOWNERS file at the top-level of this repository. This issue will be closed within 30 days of being stale.