private void ConfigureVirtualHostForPrefixedMatchAllHost()

in src/routingmanager/Envoy/EnvoyConfigBuilder.cs [227:307]
77 lines of code
18 McCabe index (conditional complexity)

        private void ConfigureVirtualHostForPrefixedMatchAllHost(V1Service triggerService, RoutingStateEstablisherInput routingStateEstablisherInput, IEnumerable<PodTriggerConfig> allPodTriggersInNamespace, V1ServicePort servicePort, IList<VirtualHost> httpFilterVirtualHosts)
        {
            if (routingStateEstablisherInput.IngressTriggers.Any(ingressTrigger => string.IsNullOrWhiteSpace(ingressTrigger.Host) && string.IsNullOrWhiteSpace(ingressTrigger.AgicBackendHostName))
                                || routingStateEstablisherInput.LoadBalancerTrigger != null)
            {
                foreach (var podTrigger in allPodTriggersInNamespace)
                {
                    // If we have already configured virtual host for another pod trigger with the same route on header value, so skipping this pod trigger
                    var existingVirtualHost = httpFilterVirtualHosts.Where(virtualHost => FirstDomainStartsWithRoutingHeaderValue(virtualHost.Domains, podTrigger.RouteOnHeader.Value)).FirstOrDefault();
                    if (existingVirtualHost != null)
                    {
                        // Handle the case where two same routing header value are present for podTrigger
                        if (routingStateEstablisherInput.PodTriggers != null && routingStateEstablisherInput.PodTriggers.Contains(podTrigger))
                        {
                            // This is safe to assume RouteElement and a Cluster are not null as they are defined below.
                            existingVirtualHost.Routes.First().Route.Cluster = string.Format(_serviceStableWithHeaderWithPortsFormatString, podTrigger.RouteOnHeader.Key, podTrigger.RouteOnHeader.Value, servicePort.Port, servicePort.TargetPort.Value);
                        }
                        else
                        {
                            _log.Info("While configuring envoy for ingress triggers, Another pod trigger with the same routing header value '{0}' was already used for configuring the ingress triggers, so skipping this pod trigger"
                            , new PII(podTrigger.RouteOnHeader.Value));
                        }
                        continue;
                    }

                    _log.Info("Configuring envoy for service '{0}' for port '{1}' for empty host : Pod trigger : '{2}'", new PII(triggerService.Metadata.Name), new PII(servicePort.Port.ToString()), new PII(podTrigger.TriggerEntityName));

                    var domains = new List<string> { $"{podTrigger.RouteOnHeader.Value}.*" };
                    var ingressVirtualHost =
                        new VirtualHost
                        {
                            // We are only adding the rule for domain starting with routing header. We are not adding the catch all * here on purpose.
                            // This is because there is at least one pod trigger for sure. We will be adding the * catch all rule as part of that.
                            Name = $"listener_{servicePort.Port}_{servicePort.TargetPort.Value}_route_ingress_withDomain_{string.Join(',', domains)}",
                            Domains = domains,
                            Routes = new List<RouteElement>
                            {
                                new RouteElement
                                {
                                    Match = new Match
                                    {
                                        Prefix = "/"
                                    },
                                    // Will add Route below
                                    RequestHeadersToAdd = new List<RequestHeadersToAdd>
                                    {
                                        new RequestHeadersToAdd
                                        {
                                            Header = new RequestHeaderToAdd
                                            {
                                                Key = podTrigger.RouteOnHeader.Key,
                                                Value = podTrigger.RouteOnHeader.Value
                                            },
                                            Append = false
                                        }
                                    }
                                }
                            }
                        };

                    if (routingStateEstablisherInput.PodTriggers != null && routingStateEstablisherInput.PodTriggers.Contains(podTrigger))
                    {
                        // This means input.TriggerService has an ingress and pod trigger both, so we need to route to service_stable for the given domains
                        ingressVirtualHost.Routes.First().Route = new Route
                        {
                            Cluster = string.Format(_serviceStableWithHeaderWithPortsFormatString, podTrigger.RouteOnHeader.Key, podTrigger.RouteOnHeader.Value, servicePort.Port, servicePort.TargetPort.Value)
                        };
                    }
                    else
                    {
                        ingressVirtualHost.Routes.First().Route = new Route
                        {
                            Cluster = string.Format(_serviceCloneWithPortsFormatString, servicePort.Port, servicePort.TargetPort.Value)
                        };
                    }

                    // Add to the last added listener above. There is always only a single Filter chain and a single filter in that.
                    httpFilterVirtualHosts.Add(ingressVirtualHost);
                }
            }
        }