Adds PROMQL source command

lib/elastic/esql.rb

@@ -32,6 +32,7 @@
 require_relative 'metadata'
 require_relative 'metrics_info'
 require_relative 'mv_expand'
+require_relative 'promql'
 require_relative 'queryable'
 require_relative 'registered_domain'
 require_relative 'rename'
@@ -54,11 +55,11 @@ module Elastic
   class ESQL
     [
       ChangePoint, Custom, Dissect, Drop, Eval, Fork, Fuse, Grok, InlineStats, Keep, LookupJoin,
-      Metadata, MetricsInfo, MvExpand, Queryable, RegisteredDomain, Rename, Row, Sample,
+      Metadata, MetricsInfo, MvExpand, PromQL, Queryable, RegisteredDomain, Rename, Row, Sample,
       SetDirective, Show, Stats, StatsMixin, TS, URIParts, Util
     ].each { |m| include m }
 
-    SOURCE_COMMANDS = [:from, :row, :show, :ts].freeze
+    SOURCE_COMMANDS = [:from, :promql, :row, :show, :ts].freeze
 
     def initialize
       @query = {}
@@ -107,6 +108,12 @@ def self.from(index_pattern)
       new.from(index_pattern)
     end
 
+    # Class method to allow static instantiation.
+    # @see PromQL#promql
+    def self.promql(params)
+      new.promql(params)
+    end
+
     # The SHOW source command returns information about the deployment and its capabilities.
     # @return [String] 'SHOW INFO'
     # @see https://www.elastic.co/docs/reference/query-languages/esql/commands/source-commands#esql-show

lib/elastic/promql.rb

@@ -0,0 +1,85 @@
+# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+# or more contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Elasticsearch B.V. licenses this file to you under
+# the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+module Elastic
+  # The PROMQL source command queries time series indices using Prometheus Query Language (PromQL).
+  # Like TS, it enables time series aggregation functions, but accepts PromQL syntax instead of
+  # ES|QL.
+  module PromQL
+    PROMQL_PARAMETERS = [:index, :step, :buckets, :start, :end, :scrape_interval, :result, :expression].freeze
+    # @param [Hash] params The PROMQL command accepts zero or more space-separated key value options
+    #                      followed by named PromQL expression.
+    # @option params [String] :index A list of indices, data streams, or aliases. Supports wildcards
+    #                                and date math. Defaults to * querying all indices with
+    #                                index.mode: time_series.
+    # @option params [String] :step Query resolution step width (optional). Automatically determined
+    #                               given the number of target +buckets+ and the selected time
+    #                               range.
+    # @option params [String] :buckets Target number of buckets for auto-step derivation. Defaults
+    #                                  to +100+. Mutually exclusive with +step+. Requires a known
+    #                                  time range, either by setting start and end explicitly or
+    #                                  implicitly through Kibana's time range filter.
+    # @option params [String] :start Start time of the query, inclusive (optional). Uses the start
+    #                                based on Kibana's date picker or unrestricted if missing.
+    # @option params [String] :end End time of the query, inclusive (optional). Uses the end based
+    #                              on Kibana's date picker or unrestricted if missing.
+    # @option params [String] :scrape_interval The expected metric collection interval. Defaults to
+    #                                          +1m+. Used to determine implicit range selector
+    #                                          windows as +max(step, scrape_interval)+.
+    # @option params [String] :result Name of the output column with the query result timeseries
+    #                                 (optional). By default, the name of the output column is the
+    #                                 PromQL expression itself.
+    #
+    # @example
+    #   Elastic::ESQL.promql(index: 'k8', step: '1h', result: 'result', expression: '(sum by (cluster) (network.cost))')
+    #
+    # @see https://www.elastic.co/docs/reference/query-languages/esql/commands/promql
+    #
+    def promql(params)
+      validate_params(params.keys)
+      @query[:promql] = promql_query(params)
+      self
+    end
+
+    private
+
+    def validate_params(params)
+      params.each do |param|
+        raise ArgumentError, "#{param} is not a valid parameter for PROMQL" unless PROMQL_PARAMETERS.include?(param)
+      end
+    end
+
+    def promql_query(params)
+      query = []
+      result = params.delete(:result)
+      expression = params.delete(:expression)
+      query += process_promql_params(params)
+      query << (result ? "#{result}=#{expression}" : expression)
+      query.join(' ')
+    end
+
+    def process_promql_params(params)
+      params.map do |k, v|
+        if [:start, :end].include?(k)
+          "#{k}=\"#{v}\""
+        else
+          "#{k}=#{v}"
+        end
+      end
+    end
+  end
+end

spec/promql_spec.rb

@@ -0,0 +1,74 @@
+# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+# or more contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Elasticsearch B.V. licenses this file to you under
+# the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+require 'spec_helper'
+
+# rubocop:disable Metrics/BlockLength
+describe Elastic::ESQL do
+  context 'PROMQL' do
+    it 'builds a query with index' do
+      esql = ESQL.promql(index: 'metrics-*', expression: 'sum by (instance) (rate(http_requests_total))')
+      expect(esql.query).to eq 'PROMQL index=metrics-* sum by (instance) (rate(http_requests_total))'
+    end
+
+    it 'builds a query with more parameters' do
+      esql = ESQL.promql(
+        index: 'k8s',
+        step: '5m',
+        start: '2024-05-10T00:20:00.000Z',
+        end: '2024-05-10T00:25:00.000Z',
+        expression: '(sum(avg_over_time(network.cost[5m])))'
+      )
+      expect(esql.query).to eq 'PROMQL index=k8s step=5m ' \
+                               'start="2024-05-10T00:20:00.000Z" ' \
+                               'end="2024-05-10T00:25:00.000Z" ' \
+                               '(sum(avg_over_time(network.cost[5m])))'
+    end
+
+    it 'buils a query with named result' do
+      esql = ESQL.promql(
+        index: 'k8s',
+        step: '1h',
+        result: 'result',
+        expression: '(sum by (cluster) (network.cost))'
+      ).sort('result')
+      expect(esql.query).to eq 'PROMQL index=k8s step=1h ' \
+                               'result=(sum by (cluster) (network.cost)) ' \
+                               '| SORT result'
+    end
+
+    it 'buils another query from the examples' do
+      expression = '(max by (cluster) (network.total_bytes_in{cluster!="prod"}))'
+      esql = ESQL.promql(
+        index: 'k8s',
+        step: '1h',
+        result: 'cost',
+        expression: expression
+      ).sort('cluster')
+      expect(esql.query).to eq 'PROMQL index=k8s step=1h ' \
+                               "cost=#{expression} " \
+                               '| SORT cluster'
+    end
+
+    it 'raises error if the parameters are wrong' do
+      expect do
+        ESQL.promql(example_parameter: 'wrong')
+      end.to raise_error(ArgumentError, 'example_parameter is not a valid parameter for PROMQL')
+    end
+  end
+end
+# rubocop:enable Metrics/BlockLength