4-api.ts

private createApi(): appsync.CfnGraphQLApi {
    const name = 'Api';
    const cloudWatchLogsRoleArn = this.createApiCloudWatchRole().roleArn

    return new appsync.CfnGraphQLApi(this, name, {
        name: name,
        authenticationType: 'AWS_IAM',
        logConfig: {
            fieldLogLevel: 'ERROR',
            cloudWatchLogsRoleArn: cloudWatchLogsRoleArn
        }
    });
}

private createApiCloudWatchRole(): iam.Role {
    const name = 'ApiCloudWatchRole';

    return new iam.Role(this, name, {
        roleName: name,
        assumedBy: new iam.ServicePrincipal('appsync.amazonaws.com'),
        managedPolicies: [iam.ManagedPolicy.fromAwsManagedPolicyName('service-role/AWSAppSyncPushToCloudWatchLogs')]
    })
}