fix: JSII error while configuring image builders on Python (#469)

JSII returned `Construct` instead of `RunnerImageBuilder` because `RunnerImageBuilder` inherits from `RunnerImageBuilderBase` which is marked internal. To resolve this, we instead return the same object as a new public interface called `IConfigurableImageBuilder`.

We still want vanilla `IRunnerImageBuilder` as someone might want their own version of a builder that may not need components or network configuration. Just like `StaticRunnerImage.fromEcrRepository()``.

This probably failed on Java, .NET and Go too.

Fixes #468

src/image-builders/api.ts

@@ -2,8 +2,8 @@ import { Annotations } from 'aws-cdk-lib';
 import { Construct } from 'constructs';
 import { AwsImageBuilderRunnerImageBuilder } from './aws-image-builder';
 import { CodeBuildRunnerImageBuilder } from './codebuild';
-import { RunnerImageBuilderBase, RunnerImageBuilderProps, RunnerImageBuilderType } from './common';
-import { Os } from '../providers/common';
+import { IConfigurableRunnerImageBuilder, RunnerImageBuilderBase, RunnerImageBuilderProps, RunnerImageBuilderType } from './common';
+import { Os } from '../providers';
 
 /**
  * GitHub Runner image builder. Builds a Docker image or AMI with GitHub Runner and other requirements installed.
@@ -16,7 +16,7 @@ export abstract class RunnerImageBuilder extends RunnerImageBuilderBase {
   /**
    * Create a new image builder based on the provided properties. The implementation will differ based on the OS, architecture, and requested builder type.
    */
-  static new(scope: Construct, id: string, props?: RunnerImageBuilderProps): RunnerImageBuilder {
+  static new(scope: Construct, id: string, props?: RunnerImageBuilderProps): IConfigurableRunnerImageBuilder {
     if (props?.components && props.runnerVersion) {
       Annotations.of(scope).addWarning('runnerVersion is ignored when components are specified. The runner version will be determined by the components.');
     }

src/image-builders/common.ts

@@ -4,7 +4,7 @@ import { Construct } from 'constructs';
 import { AwsImageBuilderRunnerImageBuilderProps } from './aws-image-builder';
 import { CodeBuildRunnerImageBuilderProps } from './codebuild';
 import { RunnerImageComponent } from './components';
-import { Architecture, Os, RunnerAmi, RunnerImage, RunnerVersion } from '../providers/common';
+import { Architecture, Os, RunnerAmi, RunnerImage, RunnerVersion } from '../providers';
 
 /**
  * @internal
@@ -278,10 +278,31 @@ export interface IRunnerImageBuilder {
   bindAmi(): RunnerAmi;
 }
 
+/**
+ * Interface for constructs that build an image that can be used in {@link IRunnerProvider}. The image can be configured by adding or removing components. The image builder can be configured by adding grants or allowing connections.
+ *
+ * An image can be a Docker image or AMI.
+ */
+export interface IConfigurableRunnerImageBuilder extends IRunnerImageBuilder, ec2.IConnectable, iam.IGrantable {
+  /**
+   * Add a component to the image builder. The component will be added to the end of the list of components.
+   *
+   * @param component component to add
+   */
+  addComponent(component: RunnerImageComponent): void;
+
+  /**
+   * Remove a component from the image builder. Removal is done by component name. Multiple components with the same name will all be removed.
+   *
+   * @param component component to remove
+   */
+  removeComponent(component: RunnerImageComponent): void;
+}
+
 /**
  * @internal
  */
-export abstract class RunnerImageBuilderBase extends Construct implements ec2.IConnectable, iam.IGrantable, IRunnerImageBuilder {
+export abstract class RunnerImageBuilderBase extends Construct implements IConfigurableRunnerImageBuilder {
   protected components: RunnerImageComponent[] = [];
 
   protected constructor(scope: Construct, id: string, props?: RunnerImageBuilderProps) {
@@ -299,20 +320,10 @@ export abstract class RunnerImageBuilderBase extends Construct implements ec2.IC
   abstract get connections(): ec2.Connections;
   abstract get grantPrincipal(): iam.IPrincipal;
 
-  /**
-   * Add a component to the image builder. The component will be added to the end of the list of components.
-   *
-   * @param component component to add
-   */
   public addComponent(component: RunnerImageComponent) {
     this.components.push(component);
   }
 
-  /**
-   * Remove a component from the image builder. Removal is done by component name. Multiple components with the same name will all be removed.
-   *
-   * @param component component to remove
-   */
   public removeComponent(component: RunnerImageComponent) {
     this.components = this.components.filter(c => c.name !== component.name);
   }

src/providers/ecs.ts

@@ -222,7 +222,7 @@ export class EcsRunnerProvider extends BaseProvider implements IRunnerProvider {
    *  * `RunnerImageComponent.docker()`
    *  * `RunnerImageComponent.githubRunner()`
    */
-  public static imageBuilder(scope: Construct, id: string, props?: RunnerImageBuilderProps): RunnerImageBuilder {
+  public static imageBuilder(scope: Construct, id: string, props?: RunnerImageBuilderProps) {
     return RunnerImageBuilder.new(scope, id, {
       os: Os.LINUX_UBUNTU,
       architecture: Architecture.X86_64,

src/providers/fargate.ts

@@ -275,7 +275,7 @@ export class FargateRunnerProvider extends BaseProvider implements IRunnerProvid
    *  * `RunnerImageComponent.awsCli()`
    *  * `RunnerImageComponent.githubRunner()`
    */
-  public static imageBuilder(scope: Construct, id: string, props?: RunnerImageBuilderProps): RunnerImageBuilder {
+  public static imageBuilder(scope: Construct, id: string, props?: RunnerImageBuilderProps) {
     return RunnerImageBuilder.new(scope, id, {
       os: Os.LINUX_UBUNTU,
       architecture: Architecture.X86_64,