Dynamic service providers and arguments

[maryam4s26]

hi @andersevenrud

In your opinion, how can I control the registration of adapters and service providers through the docker-compose.yml file?

[andersevenrud]

I would suggest using (prefixed) environmental flags if you just want basic bootstrapping.

For example imagine you have two providers: Foo and Bar.

const enabledServices = process.env.OSJS_SERVICES.split(',')

if (enabledServices.includes('Foo')) {
  osjs.register(FooServiceProvider, {
    args: {
      arg1: process.env.OSJS_SERVICE_FOO_ARG1,
      arg2: process.env.OSJS_SERVICE_FOO_ARG2,
    }
  })
}
if (enabledServices.includes('Bar')) {
  osjs.register(BarServiceProvicer, {
    args: {
      arg1: process.env.OSJS_SERVICE_BAR_ARG1,
      arg2: process.env.OSJS_SERVICE_BAR_ARG2,
    }
  })
}

Then this could be set up with:

OSJS_SERVICES=Foo,Bar
OSJS_SERVICE_FOO_ARG1=Hello
OSJS_SERVICE_FOO_ARG2=World
OSJS_SERVICE_BAR_ARG1=Bye
OSJS_SERVICE_BAR_ARG2=World

---

If you need something more advanced, use something like a JSON file that you bind via a [ro] volume and just read that in your bootstrap file and do whatever you need. This can then be copied into an image in your Dockerfile or whatever for deployments.

[andersevenrud]

Just a note on dynamically registering service providers and behaviour on runtime.

To make sure things don't crash whenever a service provider has not been registered and you perform core.make('my-namespace/something') calls, etc.:

• Define the provided calls in your provides()
• Do if (core.has()) {} wrapping where you do the actual calls

---

class MyServiceProvider {
  constructor(core, options = {}) {
    this.core = core;
    this.options = options;
  }

  provides() {
    return ['my-namespace/something'];
  }

  async init() {
    this.core.singleton('my-namespace/something', () => ({
      foo: name => alert(`Hello ${name}!`)
    }));
  }
}

if (core.has('my-namespace/something')) {
  const {foo} = core.make('my-namespace/something')
  foo('World')
}

[andersevenrud]

And I just had a thought. You can actually set up the client-side providers via the backend so you don't have to compile to apply settings from the environment.

1. Create a provider on the server that sets up an endpoint that returns some kind of configuration object based on process.env like described in my first post
2. On the client bootstrap init function, do a HTTP call to the above endpoint
3. Now you can register anything like you want it

---

// Your server provider
class MyServiceProvider {
  constructor(core, options = {}) {
    this.core = core;
    this.options = options;
  }

  async init() {
    const {route} = this.core.make('osjs/express');

    route('GET', '/my-endpoint', (req, res) => {
      res.json({ services: ['Foo', 'Bar'] });
    });
  }
}

// Your client bootstrap
async function init() {
  const myConfiguration = await osjs.request('/my-endpoint');
  // ... register stuff
  // --> myConfiguration.services
}

[maryam4s26]

Thank you for your complete explanation <3

[andersevenrud]

You're very welcome!