protected override async Task <HealthCheckResult> CheckHealthInternalAsync(HealthCheckContext context, CancellationToken token)
{
string checkName = context.Registration.Name;
if (m_accessor.Value == null)
{
Logger.LogWarning(Tag.Create(), "'{0}' check executed before ServiceContext provided", checkName);
// Health check ran too early in the service lifecycle. Returning error here might force deployment rollback.
return(HealthCheckResult.Healthy("Not initialized"));
}
if (m_uriToCheck == null)
{
int port = m_accessor.Value.CodePackageActivationContext.GetEndpoint(Parameters.EndpointName).Port;
UriBuilder builder = new UriBuilder(Parameters.Scheme, Host, port, Parameters.RelativeUri.ToString());
m_uriToCheck = builder.Uri;
}
HttpClient httpClient = m_httpClientFactory.CreateClient(HttpClientLogicalName);
HttpRequestMessage request = new HttpRequestMessage(Parameters.Method, m_uriToCheck);
foreach (KeyValuePair <string, IEnumerable <string> > pair in Parameters.Headers)
{
if (!request.Headers.TryAddWithoutValidation(pair.Key, pair.Value))
{
string logMessage = string.Format(
CultureInfo.InvariantCulture,
"Cannot add request header with name '{0}' value '{1}' for health check '{2}'.",
pair.Key,
pair.Value,
checkName);
Logger.LogWarning(Tag.Create(), logMessage);
return(new HealthCheckResult(HealthStatus.Unhealthy, logMessage, data: Parameters.ReportData));
}
}
HttpResponseMessage?response = await httpClient.SendAsync(request, token).ConfigureAwait(false);
HealthStatus healthStatus = HealthStatus.Unhealthy;
string description = string.Empty;
if (response != null)
{
if (response.StatusCode == Parameters.ExpectedStatus)
{
healthStatus = HealthStatus.Healthy;
}
else
{
Logger.LogWarning(Tag.Create(), "'{0}' is unhealthy, expected request result {1}, actual {2}",
checkName, Parameters.ExpectedStatus, response.StatusCode);
// attach response to description only if check is not healthy to improve performance
description = await response.Content.ReadAsStringAsync();
}
}
HealthCheckResult result = new HealthCheckResult(healthStatus, description, data: Parameters.ReportData);
if (Parameters.AdditionalCheck != null && response != null)
{
Logger.LogInformation(Tag.Create(), "'{0}' check result will be overridden by {1}",
checkName, nameof(HttpHealthCheckParameters.AdditionalCheck));
result = Parameters.AdditionalCheck(response, result);
}
return(result);
}