/// <summary>
/// Determines whether Elasticsearch cluster is ready.
/// </summary>
public async Task <Status> IsReadyAsync(CancellationToken cancellationToken)
{
var healthRequest = new ClusterHealthRequest
{
WaitForStatus = WaitForStatus.Green
};
IClusterHealthResponse healthResponse = await _client
.ClusterHealthAsync(healthRequest, cancellationToken);
return(new Status
{
IsReady = healthResponse.IsValid,
Message = healthResponse.DebugInformation
});
}
/// <summary>
/// Checks if a single host is healthy
/// </summary>
/// <returns>The host healthy.</returns>
private async Task <bool> IsHostHealthy(string alias)
{
// Use the cluster health API to verify that the Best Bets index is functioning.
// Maps to https://ncias-d1592-v.nci.nih.gov:9299/_cluster/health/bestbets?pretty (or other server)
//
// References:
// https://www.elastic.co/guide/en/elasticsearch/reference/master/cluster-health.html
// https://github.com/elastic/elasticsearch/blob/master/rest-api-spec/src/main/resources/rest-api-spec/api/cluster.health.json#L20
try
{
IClusterHealthResponse response = await _elasticClient.ClusterHealthAsync(hd => hd.Index(alias));
if (!response.IsValid)
{
_logger.LogError($"Error checking ElasticSearch health for {alias}.");
_logger.LogError($"Returned debug info: {response.DebugInformation}.");
}
else
{
if (response.Status == "green" || response.Status == "yellow")
{
//This is the only condition that will return true
return(true);
}
else
{
_logger.LogError($"Alias ${alias} status is not good");
}
}
}
catch (Exception ex)
{
_logger.LogError($"Error checking ElasticSearch health for {alias}.");
_logger.LogError($"Exception: {ex.Message}.");
}
return(false);
}
