public static async Task LoadLayerPackageInfos()

in src/Amazon.Lambda.Tools/LambdaUtilities.cs [536:593]
50 lines of code
7 McCabe index (conditional complexity)

        public static async Task<LayerPackageInfo> LoadLayerPackageInfos(IToolLogger logger, IAmazonLambda lambdaClient, IAmazonS3 s3Client, IEnumerable<string> layerVersionArns)
        {
            var info = new LayerPackageInfo();
            if (layerVersionArns == null || !layerVersionArns.Any())
                return info;

            logger.WriteLine("Inspecting Lambda layers for runtime package store manifests");
            foreach(var arn in layerVersionArns)
            {
                try
                {
                    var p = ParseLayerVersionArn(arn);
                    var getLayerResponse = await lambdaClient.GetLayerVersionAsync(new GetLayerVersionRequest { LayerName = p.Name, VersionNumber = p.VersionNumber });

                    LayerDescriptionManifest manifest;
                    if (!LambdaUtilities.AttemptToParseLayerDescriptionManifest(getLayerResponse.Description, out manifest))
                    {
                        logger.WriteLine($"... {arn}: Skipped, does not contain a layer description manifest");
                        continue;
                    }
                    if (manifest.Nlt != LayerDescriptionManifest.ManifestType.RuntimePackageStore)
                    {
                        logger.WriteLine($"... {arn}: Skipped, layer is of type {manifest.Nlt.ToString()}, not {LayerDescriptionManifest.ManifestType.RuntimePackageStore}");
                        continue;
                    }

                    string GetLastArnComponent(string input)
                    {
                        return input.Substring(input.LastIndexOf(':') + 1);
                    }

                    var layerName = GetLastArnComponent(getLayerResponse.LayerArn);
                    var layerVers = GetLastArnComponent(getLayerResponse.LayerVersionArn);

                    var tempPath = Directory.CreateDirectory(Path.Combine(Path.GetTempPath(), Path.GetRandomFileName()));
                    var filePath = Path.Combine(tempPath.FullName, $"{layerName}-v{layerVers}.xml");

                    using (var getResponse = await s3Client.GetObjectAsync(manifest.Buc, manifest.Key))
                    using (var reader = new StreamReader(getResponse.ResponseStream))
                    {
                        await getResponse.WriteResponseStreamToFileAsync(filePath, false, default(System.Threading.CancellationToken));
                    }

                    logger.WriteLine($"... {arn}: Downloaded package manifest for runtime package store layer");
                    info.Items.Add(new LayerPackageInfo.LayerPackageInfoItem
                    {
                        Directory = manifest.Dir,
                        ManifestPath = filePath
                    });
                }
                catch(Exception e)
                {
                    logger.WriteLine($"... {arn}: Skipped, error inspecting layer. {e.Message}");
                }
            }

            return info;
        }