public async Task <StatusResponse> Get(
[FromServices] ILoadBalancer registry,
[FromServices] IHttpClientFactory factory,
[FromServices] ILogger <StatusController> logger)
{
var configHosts = registry.GetConfig();
logger.LogInformation("STATUS request with {0} hosts configured", configHosts.Length);
using var client = factory.CreateClient("status");
async Task <string?> GetStatus(Uri statusUri, CancellationToken token)
{
try
{
var response = await client.GetAsync(statusUri, HttpCompletionOption.ResponseContentRead, token);
if (response.IsSuccessStatusCode)
{
var responseContent = await response.Content.ReadAsStringAsync();
return(responseContent);
}
logger.LogError("Error getting /STATUS from {0}: got {1}", statusUri, response.StatusCode);
return(null);
}
catch (Exception e)
{
logger.LogError("Error getting /STATUS from {0}: {1}", statusUri, e.Message);
return(null);
}
}
var cts = new CancellationTokenSource(4000);
var responses = await Task.WhenAll(
from host in configHosts
let statusUri = new Uri(new Uri(host.HostUri), "/status")
select GetStatus(statusUri, cts.Token)
);
var stats = new StatusResponse();
foreach (var statusPayload in responses.Where(r => !string.IsNullOrEmpty(r)))
{
var hs = JsonSerializer.Deserialize <StatusResponse>(statusPayload);
stats.Merge(hs);
}
return(stats);
}
private async Task SyncConfig(CancellationToken cancellationToken)
{
var runningHosts = _balancer.GetConfig().ToDictionary(c => new Uri(c.HostUri), c => c);
var newConfig = _configOptions.CurrentValue;
var newHosts = newConfig.Hosts.ToDictionary(c => new Uri(c.HostUri), c => c);
// TODO optimize alive-ness request
// var consideredAlive = _sessionHandler.GetAliveHosts(DateTimeOffset.Now - TimeSpan.FromSeconds(30));
var hostsStatus = await CheckAliveStatus(from h in newConfig.Hosts select new Uri(h.HostUri));
Predicate <Uri> isAlive = uri =>
hostsStatus.TryGetValue(uri, out var x) && x &&
newHosts.TryGetValue(uri, out var config) && config.Limit > 0;
var toBeRemoved =
(from host in runningHosts.Keys
where !newHosts.ContainsKey(host) || !isAlive(host)
select host).ToArray();
var toBeStarted =
(from host in newHosts.Keys
where (!runningHosts.ContainsKey(host) || !areConfigsEqual(newHosts[host], runningHosts[host])) && isAlive(host)
select host).ToArray();
if (toBeRemoved.Any() || toBeStarted.Any())
{
_logger.LogInformation("Detected changes in configuration or availability of the hosts");
}
await Task.WhenAll(
from host in toBeRemoved
select _balancer.DeleteHost(host)
);
await Task.WhenAll(
from host in toBeStarted
select _balancer.AddHost(newHosts[host])
);
// TODO update status monitor queue
// if (hostsStatus.Any(status => status.Value == false))
// {
// var deadHosts = from h in newConfig.Hosts where !isAlive(h.HostUri) select h.HostUri;
// _logger.LogWarning("Hosts not available: {0}", string.Join(", ", deadHosts.ToArray()));
// }
}