Provider Registry

Diverge uses a pluggable, extensible architecture via its generic Registry[T] pattern. This allows you to add custom routing, deployer, notifier, testing, or database providers with zero changes to the core controller logic.

What the registry does

The Provider Registry manages implementations of different interfaces. When you configure Diverge to use a specific provider (e.g., --routing-provider=gateway), the registry looks up the correct implementation and initializes it.

How to add a provider

You can add a new provider with just a single file using the init() pattern. This automatically registers the provider when the package is imported.

Example: Adding a Linkerd Router

Create a file internal/routing/linkerd/register.go:

package linkerd

import (
  "github.com/divergedev/diverge/internal/routing"
  "github.com/divergedev/diverge/pkg/registry"
)

func init() {
  routing.Providers.Register("linkerd", registry.Provider[routing.Router]{
    Create: func(deps registry.Deps) (routing.Router, error) {
      return &LinkerdRouter{Client: deps.Client}, nil
    },
    Description: "Linkerd SMI-based routing",
  })
}

type LinkerdRouter struct {
  Client client.Client
}

// Implement routing.Router interface methods...

Then add a blank import in cmd/controller/main.go (or a providers_linkerd.go file):

import _ "github.com/divergedev/diverge/internal/routing/linkerd"

That’s it — the controller will now accept --routing-provider=linkerd.

Available provider types

The registry currently supports plugging in custom implementations for:

• Routing (routing.Router) — How traffic is directed (e.g., Gateway API, Istio, Linkerd).
• Deployer (deployer.Deployer) — How manifests are applied (e.g., DirectDeployer, ArgoCD, Knative).
• Notifier (notifier.Notifier) — How MR/PR updates are communicated (e.g., GitHub, GitLab).
• Testing (testing.TestRunner) — How integration tests are executed.
• Database (database.DatabaseProvider) — How databases are provisioned for preview environments.