public async Task <HealthCheckStatus> Check()
{
var now = DateTimeOffset.Now;
if (_lastStatus == null || (_cacheFailures && _lastStatus.HasFailed) || _lastChecked + _cacheTime < now)
{
_lastStatus = await _healthCheck.Check().ConfigureAwait(false);
_lastChecked = now;
return(_lastStatus);
}
return(_lastStatus);
}
public override async Task <HealthCheckStatus> Check()
{
var request = (HttpWebRequest)WebRequest.Create(_uri);
request.UserAgent = "Owin.HealthCheck";
request.Method = "GET";
request.Credentials = _credentials;
using (var response = (HttpWebResponse)await request.GetResponseAsync().ConfigureAwait(false))
{
var statusCode = (int)response.StatusCode;
if (statusCode >= 200 && statusCode < 300)
{
return(HealthCheckStatus.Passed(response.StatusDescription));
}
else
{
return(HealthCheckStatus.Failed(response.StatusDescription));
}
}
}
public override async Task Invoke(IOwinContext context)
{
// Make sure this is an absolute path.
if (!string.IsNullOrEmpty(context.Request.Path.Value))
{
await Next.Invoke(context);
return;
}
var queryParameters = context.Request.GetQueryParameters();
var debug = false;
if (queryParameters.ContainsKey("debug"))
{
bool.TryParse(queryParameters["debug"], out debug);
}
var checkTasks = _healthChecks.Select(async x =>
{
try
{
return(new
{
Name = x.Name,
Status = await x.Check().ConfigureAwait(false)
});
}
catch (Exception e)
{
return(new
{
Name = x.Name,
Status = HealthCheckStatus.Failed(e.Message)
});
}
});
var allTasks = Task.WhenAll(checkTasks.ToArray());
if (allTasks != await Task.WhenAny(allTasks, Task.Delay(_timeout)).ConfigureAwait(false))
{
context.Response.StatusCode = (int)HttpStatusCode.GatewayTimeout;
}
else
{
var results = allTasks.Result;
var hasFailed = results.Any(x => x.Status.HasFailed);
context.Response.StatusCode = hasFailed ? (int)HttpStatusCode.ServiceUnavailable : (int)HttpStatusCode.OK;
if (debug)
{
var sb = new StringBuilder();
foreach (var r in results)
{
sb.AppendLine(r.Name + ": " + r.Status.Message);
}
await context.Response.WriteAsync(sb.ToString());
}
}
}