private void UpdateRuntimeBackends(DynamicConfigRoot config)
{
var desiredBackends = new HashSet <string>(StringComparer.Ordinal);
foreach (var configBackendPair in config.Backends)
{
var configBackend = configBackendPair.Value;
desiredBackends.Add(configBackendPair.Key);
_backendManager.GetOrCreateItem(
itemId: configBackendPair.Key,
setupAction: backend =>
{
UpdateRuntimeEndpoints(configBackend.Endpoints, backend.EndpointManager);
var newConfig = new BackendConfig(
new BackendConfig.BackendHealthCheckOptions(
enabled: configBackend.HealthCheckOptions?.Enabled ?? false,
interval: configBackend.HealthCheckOptions?.Interval ?? TimeSpan.FromSeconds(0),
timeout: configBackend.HealthCheckOptions?.Timeout ?? TimeSpan.FromSeconds(0),
port: configBackend.HealthCheckOptions?.Port ?? 0,
path: configBackend.HealthCheckOptions?.Path ?? string.Empty),
new BackendConfig.BackendLoadBalancingOptions(
mode: configBackend.LoadBalancing?.Mode ?? default));
var currentBackendConfig = backend.Config.Value;
if (currentBackendConfig == null ||
currentBackendConfig.HealthCheckOptions.Enabled != newConfig.HealthCheckOptions.Enabled ||
currentBackendConfig.HealthCheckOptions.Interval != newConfig.HealthCheckOptions.Interval ||
currentBackendConfig.HealthCheckOptions.Timeout != newConfig.HealthCheckOptions.Timeout ||
currentBackendConfig.HealthCheckOptions.Port != newConfig.HealthCheckOptions.Port ||
currentBackendConfig.HealthCheckOptions.Path != newConfig.HealthCheckOptions.Path)
{
if (currentBackendConfig == null)
{
_logger.LogDebug("Backend {backendId} has been added.", configBackendPair.Key);
}
else
{
_logger.LogDebug("Backend {backendId} has changed.", configBackendPair.Key);
}
// Config changed, so update runtime backend
backend.Config.Value = newConfig;
}
});
}
foreach (var existingBackend in _backendManager.GetItems())
{
if (!desiredBackends.Contains(existingBackend.BackendId))
{
// NOTE 1: This is safe to do within the `foreach` loop
// because `IBackendManager.GetItems` returns a copy of the list of backends.
//
// NOTE 2: Removing the backend from `IBackendManager` is safe and existing
// ASP .NET Core endpoints will continue to work with their existing behavior (until those endpoints are updated)
// and the Garbage Collector won't destroy this backend object while it's referenced elsewhere.
_logger.LogDebug("Backend {backendId} has been removed.", existingBackend.BackendId);
_backendManager.TryRemoveItem(existingBackend.BackendId);
}
}
}