Config Service

wasmCloud hosts can be configured at start time with a variety of host config options. However, in some production deploys, it is useful to provide supplemental configuration to a host from an external source.

For example, wasmCloud hosts can be configured to pull artifacts from private OCI registries. The host can be started with credentials to a single registry, but in cases where multiple registries are used to host artifacts, a config service can be used to provide credentials for multiple registries to hosts.

The config service is disabled by default. When enabled, wasmCloud hosts will make a request to wasmbus.cfg.{lattice-id}.req during initialization.

Config Requests and Responses

When making a request for configuration, the host provides its labels as the payload:

json

{
    "labels": {
        "foo": "bar",
        "baz": "qux"
    }
}

In response, the host receives supplemental configuration. At this time, the only configuration returned is a set of credentials for OCI registries:

json

{
    "registryCredentials": {
        "someregistry.io": {
            "username": "user1",
            "password": "hunter2"
        },
        "anotherregistry.io": {
            "username": "myuser",
            "password": "asecurepassword"
        }
    }
}

Hosting a Config Service

Since the config service API is over NATS, it can be implemented by anything that can subscribe and publish responses to wasmbus.cfg.{lattice-id}.req (including a wasmCloud component!).