private void FetchServices(Timer obj)
{
var knownServices = RemoteServerManager.GetAllGroups().SelectMany(g => g.GetAllRemoteServers()).Select(s => s.ID);
var joined = registry.Keys.Except(knownServices);
var left = knownServices.Except(registry.Keys);
foreach (ushort joinedID in joined)
{
if (joinedID != RemoteServerManager.ServerID)
{
RegistryEntry service = registry[joinedID];
string group = service.Group;
Logger.Trace($"Discovered server {joinedID} from group '{group}'.");
HandleServerJoin(joinedID, group, service.Host, service.Port, new Dictionary <string, string>(service.Properties));
}
}
//TODO consider just a set method instead of/as well as join/leave
foreach (ushort leftID in left)
{
if (leftID != RemoteServerManager.ServerID)
{
Logger.Trace($"Server {leftID} has left the cluster.");
HandleServerLeave(leftID);
}
}
}
/// <summary>
/// Pulls the current services from Consul and updates the server with any changes to that list.
/// </summary>
/// <returns>A task object for the operation.</returns>
protected async Task FetchServices()
{
Logger.Trace($"Refreshing services (I'm server {RemoteServerManager.ServerID}).");
// Query Consul for the current list of services
// TODO the library we use doesn't seem to allow us to get only services with a passing health check
QueryResult <CatalogService[]> result;
try
{
result = await client.Catalog.Service(serviceName);
}
catch (Exception e)
{
Logger.Error("Failed to fetch services from Consul as an exception occurred.", e);
return;
}
CatalogService[] services = result.Response;
// Map to ushort IDs
Dictionary <ushort, CatalogService> parsedServices = services.ToDictionary(s => ushort.Parse(s.ServiceID), s => s);
// Get all known sevices
// TODO if a server isn't in a group we're connected with then they're not retured here which causes us to perpetually discover them
IEnumerable <ushort> knownServices = RemoteServerManager.GetAllGroups().SelectMany(g => g.GetAllRemoteServers()).Select(s => s.ID);
// Diff the current services aginst the known services
IEnumerable <ushort> joined, left;
joined = parsedServices.Keys.Where(k => !knownServices.Contains(k));
left = knownServices.Where(k => !parsedServices.ContainsKey(k));
foreach (ushort joinedID in joined)
{
CatalogService service = parsedServices[joinedID];
string group = service.ServiceTags.First().Substring(6);
HandleServerJoin(joinedID, group, service.Address, (ushort)service.ServicePort, service.ServiceMeta);
}
//TODO consider just a set method instead of/as well as join/leave
foreach (ushort leftID in left)
{
HandleServerLeave(leftID);
}
}
