internal async Task WarnIfSidecarMisconfigured()

in src/Microsoft.Azure.WebJobs.Extensions.Dapr/Services/DaprServiceListener.cs [146:223]
66 lines of code
9 McCabe index (conditional complexity)

        internal async Task WarnIfSidecarMisconfigured()
        {
            var cancellationToken = new CancellationTokenSource(TimeSpan.FromSeconds(10)).Token;

            string resBody;

            try
            {
                var res = await this.daprClient.GetAsync(this.logger, $"{this.daprAddress}/v1.0/metadata", cancellationToken);
                resBody = await res.Content.ReadAsStringAsync();
                if (res.StatusCode != System.Net.HttpStatusCode.OK)
                {
                    throw new Exception($"Failed to query the Metadata API, received status code {res.StatusCode}, response body: {resBody}");
                }
            }
            catch (Exception ex)
            {
                this.logger.LogError($"Failed to query the Metadata API, exception: {ex}");
                return;
            }

            JsonDocument jsonDocument;

            try
            {
                jsonDocument = JsonDocument.Parse(resBody);
            }
            catch (Exception ex)
            {
                this.logger.LogError($"Failed to deserialize the Metadata API response, exception: {ex}");
                return;
            }

            JsonElement root = jsonDocument.RootElement;
            if (root.TryGetProperty("appConnectionProperties", out JsonElement appConnectionProperties))
            {
                // We set the appAddress, so it's safe to assume it's in the format we expect.
                // appAddress is in the format "http://127.0.0.1:3001"
                string[] appAddressParts = this.appAddress.Substring("http://".Length).Split(':');
                string appChannelAddress = appAddressParts[0];
                int appPort = int.Parse(appAddressParts[1]);

                try
                {
                    if (appConnectionProperties.TryGetProperty("port", out var port))
                    {
                        // port is an int in the Metadata API response.
                        var portInt = port.GetInt32();
                        if (portInt != appPort)
                        {
                            this.logger.LogWarning($"The Dapr sidecar is configured to listen on port {portInt}, but the app server is running on port {appPort}. This may cause unexpected behavior, see https://aka.ms/azfunc-dapr-app-config-error.");
                        }
                    }
                    else
                    {
                        // Daprd sidecar does not have port configured.
                        this.logger.LogWarning($"The Dapr sidecar is not configured to listen on a port, but the app server is running on port {appPort}. This may cause unexpected behavior, see https://aka.ms/azfunc-dapr-app-config-error.");
                    }

                    // channelAddress is always present in appConnectionProperties.
                    string address = appConnectionProperties.GetProperty("channelAddress").GetRawText().Trim('"');
                    if (address != appChannelAddress)
                    {
                        this.logger.LogWarning($"The Dapr sidecar is configured to listen on host {address}, but the app server is running on host {appChannelAddress}. This may cause unexpected behavior, see https://aka.ms/azfunc-dapr-app-config-error.");
                    }
                }
                catch (Exception e)
                {
                    this.logger.LogError($"Failed to parse appConnectionProperties in Metadata API response body, exception: {e}");
                    return;
                }
            }
            else
            {
                this.logger.LogDebug("appConnectionProperties not found in metadata API, skipping sidecar configuration check.");
                return;
            }
        }