collectd configuration for querying Elasticsearch using curl_json plugin

collect_elasticsearch.conf.erb

<Plugin curl_json>
  <URL "http://127.0.0.1:<%= es_port -%>/_cluster/nodes/_local/stats?http=true&process=true&jvm=true&transport=true">
    Instance "elasticsearch"

<%
stats = {
  "counter" => [
    "indices.cache.field_evictions",
    "indices.cache.filter_count",
    "indices.cache.filter_evictions",
    "indices.indexing.index_total",
    "indices.indexing.index_time_in_millis",
    "indices.indexing.delete_total",
    "indices.indexing.delete_time_in_millis",
    "indices.get.total",
    "indices.get.total_time_in_millis",
    "indices.get.exists_total",
    "indices.get.exists_time_in_millis",
    "indices.get.missing_total",
    "indices.get.missing_time_in_millis",
    "indices.flush.total",
    "indices.flush.total_time_in_millis",
    "indices.merges.total",
    "indices.merges.total_time_in_millis",
    "indices.refresh.total",
    "indices.refresh.total_time_in_millis",
    "indices.search.query_total",
    "indices.search.query_time_in_millis",
    "indices.search.fetch_current",
    "indices.search.fetch_total",
    "indices.search.fetch_time_in_millis",
    "jvm.gc.collection_count",
    "jvm.gc.collection_time_in_millis",
    "transport.rx_count",
    "transport.tx_count",
  ],
  "bytes" => [
    "indices.store.size_in_bytes",
    "indices.cache.field_size_in_bytes",
    "indices.cache.filter_size_in_bytes",
    "indices.merges.total_size_in_bytes",
    "jvm.mem.heap_used_in_bytes",
    "jvm.mem.heap_committed_in_bytes",
    "jvm.mem.non_heap_used_in_bytes",
    "jvm.mem.non_heap_committed_in_bytes",
    "transport.http.current_open",
    "transport.http.total_opened",
    "transport.rx_size_in_bytes",
    "transport.tx_size_in_bytes",
  ],
  "gauge" => [
    "indices.docs.count",
    "indices.docs.deleted",
    "indices.merges.current",
    "indices.merges.current_docs",
    "indices.merges.total_docs",
    "indices.search.query_current",
    "jvm.threads.count",
    "jvm.threads.peak_count",
    "transport.server_open",
    "http.current_open",
    "http.total_opened",
    "process.open_file_descriptors",
  ],
}

# We write out Instance because the autogenerated version only uses the last
# two parts of the key name and can produce clashes.
stats.each do |stat_type, stat_keys|
  stat_keys.each do |stat_key|
-%>
    <Key "nodes/*/<%= stat_key.gsub(".", "/") -%>">
      Type "<%= stat_type -%>"
      Instance "<%= stat_key -%>"
    </Key>
<%
  end
end
-%>
  </URL>
</Plugin>