Description

NewClient creates a new client to work with Elasticsearch.

NewClient, by default, is meant to be long-lived and shared across your application. If you need a short-lived client, e.g. for request-scope, consider using NewSimpleClient instead.

The caller can configure the new client by passing configuration options to the func.

Example:

client, err := elastic.NewClient(
  elastic.SetURL("http://127.0.0.1:9200", "http://127.0.0.1:9201"),
  elastic.SetMaxRetries(10),
  elastic.SetBasicAuth("user", "secret"))

If no URL is configured, Elastic uses DefaultURL by default.

If the sniffer is enabled (the default), the new client then sniffes the cluster via the Nodes Info API (see http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/cluster-nodes-info.html#cluster-nodes-info). It uses the URLs specified by the caller. The caller is responsible to only pass a list of URLs of nodes that belong to the same cluster. This sniffing process is run on startup and periodically. Use SnifferInterval to set the interval between two sniffs (default is 15 minutes). In other words: By default, the client will find new nodes in the cluster and remove those that are no longer available every 15 minutes. Disable the sniffer by passing SetSniff(false) to NewClient.

The list of nodes found in the sniffing process will be used to make connections to the REST API of Elasticsearch. These nodes are also periodically checked in a shorter time frame. This process is called a health check. By default, a health check is done every 60 seconds. You can set a shorter or longer interval by SetHealthcheckInterval. Disabling health checks is not recommended, but can be done by SetHealthcheck(false).

Connections are automatically marked as dead or healthy while making requests to Elasticsearch. When a request fails, Elastic will retry up to a maximum number of retries configured with SetMaxRetries. Retries are disabled by default.

If no HttpClient is configured, then http.DefaultClient is used. You can use your own http.Client with some http.Transport for advanced scenarios.

An error is also returned when some configuration option is invalid or the new client cannot sniff the cluster (if enabled).