public static SQSEventSourceProcess Startup()

in Tools/LambdaTestTool-v2/src/Amazon.Lambda.TestTool/Processes/SQSEventSource/SQSEventSourceProcess.cs [31:102]
59 lines of code
8 McCabe index (conditional complexity)

    public static SQSEventSourceProcess Startup(RunCommandSettings settings, CancellationToken cancellationToken = default)
    {
        if (string.IsNullOrEmpty(settings.SQSEventSourceConfig))
        {
            throw new InvalidOperationException($"The {nameof(RunCommandSettings.SQSEventSourceConfig)} can not be null when starting the SQS event source process");
        }

        var sqsEventSourceConfigs = LoadSQSEventSourceConfig(settings.SQSEventSourceConfig);

        var tasks = new List<Task>();

        // Create a separate SQSEventSourceBackgroundService for each SQS event source config listed in the SQSEventSourceConfig
        foreach (var sqsEventSourceConfig in sqsEventSourceConfigs)
        {
            var builder = Host.CreateApplicationBuilder();

            var sqsConfig = new AmazonSQSConfig();
            if (!string.IsNullOrEmpty(sqsEventSourceConfig.Profile))
            {
                sqsConfig.Profile = new Profile(sqsEventSourceConfig.Profile);
            }

            if (!string.IsNullOrEmpty(sqsEventSourceConfig.Region))
            {
                sqsConfig.RegionEndpoint = RegionEndpoint.GetBySystemName(sqsEventSourceConfig.Region);
            }

            var sqsClient = new AmazonSQSClient(sqsConfig);
            builder.Services.AddSingleton<IAmazonSQS>(sqsClient);
            builder.Services.AddSingleton<ILambdaClient, LambdaClient>();

            var queueUrl = sqsEventSourceConfig.QueueUrl;
            if (string.IsNullOrEmpty(queueUrl))
            {
                throw new InvalidOperationException("QueueUrl is a required property for SQS event source config");
            }

            var lambdaRuntimeApi = sqsEventSourceConfig.LambdaRuntimeApi;
            if (string.IsNullOrEmpty(lambdaRuntimeApi))
            {
                if (!settings.LambdaEmulatorPort.HasValue)
                {
                    throw new InvalidOperationException("No Lambda runtime api endpoint was given as part of the SQS event source config and the current " +
                        "instance of the test tool is not running the Lambda runtime api. Either provide a Lambda runtime api endpoint or set a port for " +
                        "the lambda runtime api when starting the test tool.");
                }
                lambdaRuntimeApi = $"http://{settings.LambdaEmulatorHost}:{settings.LambdaEmulatorPort}/";
            }

            var backgroundServiceConfig = new SQSEventSourceBackgroundServiceConfig
            {
                BatchSize = sqsEventSourceConfig.BatchSize ?? DefaultBatchSize,
                DisableMessageDelete = sqsEventSourceConfig.DisableMessageDelete ?? false,
                FunctionName = sqsEventSourceConfig.FunctionName ?? LambdaRuntimeApi.DefaultFunctionName,
                LambdaRuntimeApi = lambdaRuntimeApi,
                QueueUrl = queueUrl,
                VisibilityTimeout = sqsEventSourceConfig.VisibilityTimeout ?? DefaultVisiblityTimeout
            };

            builder.Services.AddSingleton(backgroundServiceConfig);
            builder.Services.AddHostedService<SQSEventSourceBackgroundService>();

            var app = builder.Build();
            var task = app.RunAsync(cancellationToken);
            tasks.Add(task);
        }

        return new SQSEventSourceProcess
        {
            RunningTask = Task.WhenAll(tasks)
        };
    }