docs: decision record about authentication configuration (eclipse-edc…

…#4300)

docs/developer/decision-records/2024-06-24-api-authentication-configuration/README.md

@@ -0,0 +1,54 @@
+# Api Authentication Configuration
+
+## Decision
+
+A new extension will be introduced for configuring the `ApiAuthenticationRegistry`
+
+## Rationale
+
+Recently, the `ApiAuthenticationRegistry` was introduced for associating a web context to a `AuthenticationService` in
+order to use different auth mechanism for different contexts. Currently though, this association is expressed
+in each `AuthenticationService` extension, which makes ti difficult to apply an `AuthenticationService` to a different
+context compared to the current hardcoded one.
+
+## Approach
+
+Each implementor of `AuthenticationService` will also implement an `ApiAuthenticationProvider` which will provide an
+instance of `AuthenticationService` based on the input configuration.
+
+```java
+public interface ApiAuthenticationProvider {
+
+    Result<AuthenticationService> provide(Config config);
+}
+```
+
+Those providers can be registered in a registry `ApiAuthenticationProviderRegistry`, associated with the auth type (
+basic,token, delegated, ...)
+
+```java
+public interface ApiAuthenticationProviderRegistry {
+
+    void register(String type, ApiAuthenticationProvider provider);
+
+    Result<ApiAuthenticationProvider> resolve(String type);
+}
+```
+
+Then the new extension, leveraging the partition mechanism of EDC `web.http` config, will configure the association
+between the context and the auth type in the prepare phase.
+
+For example if a user wants to configure the `TokenBasedAuthenticationService` for the `management` context, a
+configuration like this could be used:
+
+```
+web.http.management.auth.type=tokenbased
+web.http.management.auth.key.alias=vaultAlias
+```
+
+For each web context the extension will read the `auth.type` if present, and will invoke the provider for that type with
+the input configuration, associating then the created instance with the configured `context` in
+the `ApiAuthenticationRegistry`.
+
+> For backward compatibility we will leave in place the current hardcoded association
+> context <-> `AuthenticationService`

docs/developer/decision-records/README.md

@@ -56,3 +56,4 @@
 - [2023-12-19 Token Handling Refactor](./2023-12-19-token-handling-refactor/)
 - [2024-01-12 Dynamic Constraint Functions](./2024-01-12-dynamic-constraint-functions/)
 - [2024-05-24 Dataplane Selection Improvements](./2024-05-24-dataplane-selection-improvements/)
+- [2024-06-24 Api Authentication Configuration](./2024-06-24-api-authentication-configuration/)