static async Task Upstream()

in edge-modules/iotedge-diagnostics-dotnet/src/Program.cs [89:158]
58 lines of code
10 McCabe index (conditional complexity)

        static async Task Upstream(string hostname, string port, string proxy, string isNested, string workload_uri)
        {
            bool nested = string.Equals(isNested, "true");

            if (port == "443")
            {
                var httpClientHandler = new HttpClientHandler();

                if (proxy != null)
                {
                    Environment.SetEnvironmentVariable("https_proxy", proxy);
                }

                if (nested)
                {
                    await LoadTrustBundle(workload_uri);
                }

                var httpClient = new HttpClient(httpClientHandler);
                var logsUrl = string.Format("https://{0}/devices/0000/modules", hostname);
                var httpRequest = new HttpRequestMessage(HttpMethod.Get, logsUrl);
                try
                {
                    HttpResponseMessage httpResponseMessage = await httpClient.SendAsync(httpRequest, HttpCompletionOption.ResponseHeadersRead);
                    if (nested)
                    {
                        var keys = httpResponseMessage.Headers.GetValues("iothub-errorcode");
                        if (!keys.Contains("InvalidProtocolVersion"))
                        {
                            throw new Exception($"Wrong value for iothub-errorcode header");
                        }
                    }
                }
                catch (Exception ex)
                {
                    string message = ex.Message;
                    if ((ex.InnerException is AuthenticationException) && nested)
                    {
                        message += "Make sure that the parent root certificate is part of this device trustbundle. Use the command 'openssl s_client -connect parent_hostname:443' to display parent certificate chain.";
                    }

                    throw new Exception(message);
                }
            }
            else
            {
                // The current rust code never put proxy parameter when port is != than 443.
                // So the code below is never exercised. It was put there to avoid silently ignoring the proxy
                // if the rust code is changed.
                if (proxy != null)
                {
                    Uri proxyUri = new Uri(proxy);
                    IProxyClient proxyClient = MakeProxy(proxyUri);

                    // Setup timeouts
                    proxyClient.ReceiveTimeout = (int)TimeSpan.FromSeconds(60).TotalMilliseconds;
                    proxyClient.SendTimeout = (int)TimeSpan.FromSeconds(60).TotalMilliseconds;

                    // Get TcpClient to futher work
                    var client = proxyClient.CreateConnection(hostname, int.Parse(port));
                    client.GetStream();
                }
                else
                {
                    TcpClient client = new TcpClient();
                    await client.ConnectAsync(hostname, int.Parse(port));
                    client.GetStream();
                }
            }
        }