feat(appmesh): add timeout support to Routes

[skiyani]

Add support to http/http2/grpc/tpc route timeouts.

Reference links for HttpTimeout, GrpcTimeout, and TcpTimeout. (Http2 uses the HttpTimeout object).

closes aws#11643

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[sshver]

This looks fine. Just one observation, I feel we could have designed route-spec more like virtual-node-listener . Avoiding the subclasses, more like Adam mentioned is this comment on the PR.
We should also update the README file. Before the pull request to the actual master branch, update the title and description as per the guidelines.

[skiyani]

This looks fine. Just one observation, I feel we could have designed route-spec more like virtual-node-listener . Avoiding the subclasses, more like Adam mentioned is this comment on the PR.
We should also update the README file. Before the pull request to the actual master branch, update the title and description as per the guidelines.

Can you be more specific, it looks to follow the same pattern to me.

[sshver]

I was suggesting something along these line, so that we are not repeating the timeout() and the bind() function. This is just a suggestion. I have not run this code, so I am not sure this piece would work as it is. But this would reduce some lines of code.

export abstract class RouteSpec {
  /**
   * Creates an HTTP Based RouteSpec
   */
  public static http(options: HttpRouteSpecOptions): RouteSpec {
    return new RouteSpecImpl(Protocol.HTTP, options.match, undefined, options.timeout, options.weightedTargets);
  }

  /**
   * Creates an HTTP2 Based RouteSpec
   *
   */
  public static http2(options: HttpRouteSpecOptions): RouteSpec {
    return new RouteSpecImpl(Protocol.HTTP2, options.match, undefined, options.timeout, options.weightedTargets);
  }

  /**
   * Creates a TCP Based RouteSpec
   */
  public static tcp(options: TcpRouteSpecOptions): RouteSpec {
    return new RouteSpecImpl(Protocol.TCP, undefined, undefined, options.timeout, options.weightedTargets);
  }

  /**
   * Creates a GRPC Based RouteSpec
   */
  public static grpc(options: GrpcRouteSpecOptions): RouteSpec {
    return new RouteSpecImpl(Protocol.HTTP, undefined, options.match, options.timeout, options.weightedTargets);
  }

  /**
   * Called when the GatewayRouteSpec type is initialized. Can be used to enforce
   * mutual exclusivity with future properties
   */
  public abstract bind(scope: cdk.Construct): RouteSpecConfig;
}

class RouteSpecImpl extends RouteSpec {

  constructor(private readonly protocol: Protocol, 
    private readonly httpMatch: HttpRouteMatch,
    private readonly grpcMatch: GrpcRouteMatch, 
    private readonly timeout: HttpTimeout,
    public readonly weightedTargets: WeightedTarget[]) {
    super();
  }

  public bind(_scope: cdk.Construct): RouteSpecConfig {
    const prefixPath = this.httpMatch ? this.httpMatch.prefixPath : '/';
    if (prefixPath[0] != '/') {
      throw new Error(`Prefix Path must start with \'/\', got: ${prefixPath}`);
    }
    const httpConfig: CfnRoute.HttpRouteProperty = {
      action: {
        weightedTargets: renderWeightedTargets(this.weightedTargets),
      },
      match: {
        prefix: prefixPath,
      },
      timeout: this.timeout ? this.renderTimeout(this.timeout): undefined,
    };

    const tcpConfig: CfnRoute.TcpRouteProperty = {
      action: {
        weightedTargets: renderWeightedTargets(this.weightedTargets),
      },
      timeout: this.timeout ? this.renderTimeout(this.timeout): undefined,
    };

    const grpcConfig: CfnRoute.GrpcRouteProperty = {
      action: {
        weightedTargets: renderWeightedTargets(this.weightedTargets),
      },
      match: {
        serviceName: this.grpcMatch.serviceName,
      },
      timeout: this.timeout ? this.renderTimeout(this.timeout): undefined,
    };

    return {
      httpRouteSpec: this.protocol === Protocol.HTTP ? httpConfig : undefined,
      http2RouteSpec: this.protocol === Protocol.HTTP2 ? httpConfig : undefined,
      tcpRouteSpec: this.protocol === Protocol.TCP ? tcpConfig : undefined,
      grpcRouteSpec: this.protocol === Protocol.GRPC ? grpcConfig: undefined
    };
  }

  private renderTimeout(timeout: HttpTimeout): CfnRoute.HttpTimeoutProperty {
    return ({
      idle: timeout?.idle !== undefined ? {
        unit: 'ms',
        value: timeout?.idle.toMilliseconds(),
      } : undefined,
      perRequest: timeout?.perRequest !== undefined ? {
        unit: 'ms',
        value: timeout?.perRequest.toMilliseconds(),
      } : undefined,
    });
  }
}

[dfezzie]

This looks fine. Just one observation, I feel we could have designed route-spec more like virtual-node-listener . Avoiding the subclasses, more like Adam mentioned is this comment on the PR.
We should also update the README file. Before the pull request to the actual master branch, update the title and description as per the guidelines.

I like this suggestion, but let's make it a separate PR. No need to do a refactor in a feature commit

[dfezzie]

@sshver feel free to pick it up or create an issue for it