Optionally add imports by each command

Is there an existing issue that is already proposing this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe it

Currently lib doesn’t support command wise module loading.

suppose I have two commands

1. seed
2. cache:clear

Now the both commands have different requirement like seed will connect to DB and cache:clear will connect to redis

So If we run cache:clear when app will boot up it will connect to the database which is kind of not needed. Currently this is the blocker for me.

Describe the solution you’d like

To achieve this i am currently doing, However it is not perfect but can be a good starting point:-

@Module({})
export class XYZConsoleModule {
  static register(options: CLIOption): DynamicModule {
    return {
      module: XYZConsoleModule,
      imports: [...options.imports],
      providers: [...options.commands],
      exports: [],
    };
  }
}

async function bootstrap(options: CLIOption) {
  return NestFactory.createApplicationContext(
    XYZConsoleModule.register(options),
    {
      logger: false,
    },
  );
}
async function main() {
  const program = new Command();
  program
    .description('An ClI tool')
    .command('seed')
    .description('Seeds the database')
    .action(async () => {
      await bootstrap({
        imports: [
          SystemModule,
          TypeOrmModule.forFeature([Step, Badge, Trophy]),
        ],
        commands: [SeedCommand],
      });
    });
  program
    .command('cache:clear')
    .description('Clears the redis cache')
    .action(async () => {
      await bootstrap({
        imports: [SystemConfigModule, CacheManagerModule],
        commands: [CacheCommand],
      });
    });
  await program.parseAsync(process.argv);
  process.exit(0);
}
main().catch((e) => {
  console.error(e);
  process.exit(1);
});

Teachability, documentation, adoption, migration strategy

No response

What is the motivation / use case for changing the behavior?

This will optimise the boot time of base application and we are not loading any imports which are not related to each other.

[jmcdo29]

I don’t think it’s a huge “issue” per se, but it should be possible to look into Nest’s lazy loading feature and possibly speed the commands up. But I do agree that the database should already be up and running, or the need for the database should be abstracted away from the commands themselves. Multiple command setups could alleviate the issue too. I’m just looking at a different angle here

[jmcdo29]

Okay, after reading through the docs on lazy loading again, I think I can figure out a good way to write up a lazy loading example for the nest-commander docs.

@rakesh-avegenXpear I don’t think this is something that will be able to be baked into the package, but if you can provide a minimum repo with the multi-database-module setup you’ve got I can work on the lazy loading idea I have to proof of concept it with a real use case.

I think it would be too complex to figure out how to set up the configuration for nest-commander to take care of the lazy references, just figuring out how to hook up the lazy command to the service via config only, but I could be wrong and playing around with an example may give me a clear thought of how to do this.