No matter how you like to participate in developer communities, Pulumi wants to meet you there. If you want to meet other Pulumi users to share use-cases and best practices, contribute code or documentation, see us at an event, or just tell a story about something cool you did with Pulumi, you are part of our community.

Pulumi Community

I have the following method defined:
```    # Get registry info (creds and endpoint).
    def getRegistryInfo(rid):
        creds = ecr.get_credentials(registry_id=rid)
        decoded = base64.b64decode(creds.authorization_token).decode()
        parts = decoded.split(':')
        if len(parts) != 2:
            raise Exception("Invalid credentials")
        return ImageRegistry(creds.proxy_endpoint, parts[0], parts[1])```
and I'm defining an image like so:
```        my_image = Image(
            self.name,
            image_name=pulumi.Output.concat(repo.repository_url, "/", custom_image, ":v1.0.0"),
            build=f'./docker/{custom_image}', #=DockerBuild(context=f'./docker/{custom_image}'),
            registry=ECRRepo.getRegistryInfo(repo.registry_id)
        )```
where repo is an `ecr.Repository` object.

when I run my program I get the following error:
```Exception: invoke of aws:ecr/getCredentials:getCredentials failed: Missing required argument: The argument "registry_id" is required, but no definition was found. ()```

Not sure what I'm missing, but I'd expect copy/pasting from this example would just work™

:wave::skin-tone-4: hey! trying to figure out where this code is in the post you linked

In any case, I think in your image definition you might need to do something like:
```registry=repo.registry_id.apply(getRegistryInfo)```

ECRRepo was the class containing  the `getRegistryInfo`  ~class~ method. I was confused, clearly, on how this all works

outputs and apply are definitely some of the trickiest parts of the pulumi learning curve. <https://www.pulumi.com/docs/intro/concepts/inputs-outputs/|This doc> kinda goes into it how it all works.