Add Health Checks into Docker Startup

[StuartFerguson]

protected List<(IContainerService,Int32, String)> HealthCheckContainers;

private async Task PerformHealthChecks(CancellationToken cancellationToken)
{
foreach ((IContainerService container, Int32 port, String protocol) healthCheckContainer in this.HealthCheckContainers)
{
await Retry.For(async () =>
{
// Get the local port
Int32 exposedPort = healthCheckContainer.container.ToHostExposedEndpoint($"{healthCheckContainer.port}/tcp").Port;

                                // Build Uri
                                String requestUri = $"{healthCheckContainer.protocol}://127.0.0.1:{exposedPort}/health";

                                HttpClientHandler clientHandler = new HttpClientHandler
                                                                  {
                                                                      ServerCertificateCustomValidationCallback = (message,
                                                                          certificate2,
                                                                          arg3,
                                                                          arg4) =>
                                                                      {
                                                                          return true;
                                                                      }
                                                                  };

                                HttpClient client = new HttpClient(clientHandler);
                                HttpRequestMessage requestMessage = new HttpRequestMessage(HttpMethod.Get, requestUri);

                                HttpResponseMessage responseMessage = await client.SendAsync(requestMessage, cancellationToken);

                                var content = await responseMessage.Content.ReadAsStringAsync(cancellationToken);

                                responseMessage.StatusCode.ShouldBe(HttpStatusCode.OK, content);
                            });
        }
    }

[StuartFerguson]

1. Standardise the docker helper setup
2. Merge in any custom settings as required for each service
3. Create a start container methid that will start up the whole system (outside ACL containers, they should only started as required)
   Need to build a picture of the container dependencies for this
4. Have some way of overriding a container setup if required rather than having to update the nuget class each time
5. A method of checking the health status of the system (after all the containers have been started)
6. Upgrade the health check writer to adjust the output format

private static Task WriteResponse(HttpContext context, HealthReport healthReport) {
context.Response.ContentType = "application/json; charset=utf-8";

        var options = new JsonWriterOptions { Indented = true };

        using var memoryStream = new MemoryStream();
        using (var jsonWriter = new Utf8JsonWriter(memoryStream, options))
        {
            jsonWriter.WriteStartObject();
            jsonWriter.WriteString("status", healthReport.Status.ToString());
            jsonWriter.WriteString("totalDuration", healthReport.TotalDuration.ToString());
            jsonWriter.WriteStartArray("results");
            foreach (var healthReportEntry in healthReport.Entries)
            {
                jsonWriter.WriteStartObject();
                jsonWriter.WriteString("name",
                                       healthReportEntry.Key);
                jsonWriter.WriteString("status",
                                       healthReportEntry.Value.Status.ToString());
                jsonWriter.WriteString("duration",
                                       healthReportEntry.Value.Duration.ToString());
                jsonWriter.WriteString("description",
                                       healthReportEntry.Value.Description);
                jsonWriter.WriteStartArray("tags");
                foreach (String valueTag in healthReportEntry.Value.Tags) {
                    jsonWriter.WriteStringValue(valueTag);
                }
                jsonWriter.WriteEndArray();
                jsonWriter.WriteEndObject();
            }
            jsonWriter.WriteEndArray();
            jsonWriter.WriteEndObject();
        }

        return context.Response.WriteAsync(
                                           Encoding.UTF8.GetString(memoryStream.ToArray()));
    }

7. Create a generic Health Check client

public interface IHealthCheckClient
{
Task PerformHealthCheck(String uri, Int32 port, CancellationToken cancellationToken);
}

public class HealthCheckClient : ClientProxyBase, IHealthCheckClient
{
    public HealthCheckClient(HttpClient client) : base(client) {
        
    }
    public async Task<HealthCheckResult> PerformHealthCheck(String uri, Int32 port, CancellationToken cancellationToken) {

        String requestUri = BuildRequestUri(uri, port);

        HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, requestUri);
        
        HttpResponseMessage responseMessage = await this.HttpClient.SendAsync(request);

        String responseData = await HandleResponse(responseMessage, cancellationToken);

        return JsonConvert.DeserializeObject<HealthCheckResult>(responseData);
    }

    private String BuildRequestUri(String uri,
                                   Int32 port) {
        return $"http://{uri}:{port}/health";
    }
}

public class DependencyServiceResult
{
    public string name { get; set; }
    public HealthCheckStatus status { get; set; }
    public TimeSpan duration { get; set; }
    public List<string> tags { get; set; }
}

public class HealthCheckResult
{
    public HealthCheckStatus status { get; set; }
    public TimeSpan totalDuration { get; set; }
    public List<DependencyServiceResult> results { get; set; }
}

public enum HealthCheckStatus
{
    Unhealthy = 0,
    Degraded = 1,
    Healthy = 2,
}

[StuartFerguson]

Jobs added to November 2022 sprint