static async Task Handler()

in src/infra/docs-lambda-index-publisher/Program.cs [26:78]
50 lines of code
6 McCabe index (conditional complexity)

static async Task<SQSBatchResponse> Handler(SQSEvent ev, ILambdaContext context)
{
	var s3Client = new AmazonS3Client();
	var linkIndexProvider = new LinkIndexProvider(s3Client, context.Logger, bucketName, indexFile);
	var batchItemFailures = new List<SQSBatchResponse.BatchItemFailure>();
	foreach (var message in ev.Records)
	{
		context.Logger.LogInformation("Processing message {MessageId}", message.MessageId);
		context.Logger.LogInformation("Message body: {MessageBody}", message.Body);
		try
		{
			var s3RecordLinkReferenceTuples = await GetS3RecordLinkReferenceTuples(s3Client, message, context);
			foreach (var (s3Record, linkReference) in s3RecordLinkReferenceTuples)
			{
				var newEntry = ConvertToLinkIndexEntry(s3Record, linkReference);
				await linkIndexProvider.UpdateLinkIndexEntry(newEntry);
			}
		}
		catch (Exception e)
		{
			// Add failed message identifier to the batchItemFailures list
			context.Logger.LogWarning(e, "Failed to process message {MessageId}", message.MessageId);
			batchItemFailures.Add(new SQSBatchResponse.BatchItemFailure
			{
				ItemIdentifier = message.MessageId
			});
		}
	}
	try
	{
		await linkIndexProvider.Save();
		var response = new SQSBatchResponse(batchItemFailures);
		if (batchItemFailures.Count > 0)
			context.Logger.LogInformation("Failed to process {batchItemFailuresCount} of {allMessagesCount} messages. Returning them to the queue.", batchItemFailures.Count, ev.Records.Count);
		var jsonStr = JsonSerializer.Serialize(response, SerializerContext.Default.SQSBatchResponse);
		context.Logger.LogInformation(jsonStr);
		return response;
	}
	catch (Exception ex)
	{
		// If we fail to update the link index, we need to return all messages to the queue
		// so that they can be retried later.
		context.Logger.LogError("Failed to update {bucketName}/{indexFile}. Returning all {recordCount} messages to the queue.", bucketName, indexFile, ev.Records.Count);
		context.Logger.LogError(ex, ex.Message);
		var response = new SQSBatchResponse(ev.Records.Select(r => new SQSBatchResponse.BatchItemFailure
		{
			ItemIdentifier = r.MessageId
		}).ToList());
		var jsonStr = JsonSerializer.Serialize(response, SerializerContext.Default.SQSBatchResponse);
		context.Logger.LogInformation(jsonStr);
		return response;
	}
}