diff --git a/changelogs/unreleased/58839-automatically-set-prometheus-step-interval.yml b/changelogs/unreleased/58839-automatically-set-prometheus-step-interval.yml new file mode 100644 index 0000000000000000000000000000000000000000..2c6edf45ae21780222280b047d2dcaba805f8b10 --- /dev/null +++ b/changelogs/unreleased/58839-automatically-set-prometheus-step-interval.yml @@ -0,0 +1,5 @@ +--- +title: Automatically set Prometheus step interval +merge_request: 26441 +author: +type: changed diff --git a/lib/gitlab/prometheus_client.rb b/lib/gitlab/prometheus_client.rb index 45828c77a33b529a13305950eefc936ab51d83ee..b4de7cd2bce3efec9e2e58f4e6689c4b0429b4d2 100644 --- a/lib/gitlab/prometheus_client.rb +++ b/lib/gitlab/prometheus_client.rb @@ -6,6 +6,14 @@ class PrometheusClient Error = Class.new(StandardError) QueryError = Class.new(Gitlab::PrometheusClient::Error) + # Target number of data points for `query_range`. + # Please don't exceed the limit of 11000 data points + # See https://github.com/prometheus/prometheus/blob/91306bdf24f5395e2601773316945a478b4b263d/web/api/v1/api.go#L347 + QUERY_RANGE_DATA_POINTS = 600 + + # Minimal value of the `step` parameter for `query_range` in seconds. + QUERY_RANGE_MIN_STEP = 60 + attr_reader :rest_client, :headers def initialize(rest_client) @@ -23,12 +31,18 @@ def query(query, time: Time.now) end def query_range(query, start: 8.hours.ago, stop: Time.now) + start = start.to_f + stop = stop.to_f + step = self.class.compute_step(start, stop) + get_result('matrix') do - json_api_get('query_range', - query: query, - start: start.to_f, - end: stop.to_f, - step: 1.minute.to_i) + json_api_get( + 'query_range', + query: query, + start: start, + end: stop, + step: step + ) end end @@ -40,6 +54,14 @@ def series(*matches, start: 8.hours.ago, stop: Time.now) json_api_get('series', 'match': matches, start: start.to_f, end: stop.to_f) end + def self.compute_step(start, stop) + diff = stop - start + + step = (diff / QUERY_RANGE_DATA_POINTS).ceil + + [QUERY_RANGE_MIN_STEP, step].max + end + private def json_api_get(type, args = {}) diff --git a/spec/lib/gitlab/prometheus_client_spec.rb b/spec/lib/gitlab/prometheus_client_spec.rb index 4c3b8deefb913e3f462c152d622d90df04789b68..2517ee71f24b39a8e06ae490a37802442083f49b 100644 --- a/spec/lib/gitlab/prometheus_client_spec.rb +++ b/spec/lib/gitlab/prometheus_client_spec.rb @@ -230,4 +230,32 @@ let(:execute_query) { subject.query_range(prometheus_query) } end end + + describe '.compute_step' do + using RSpec::Parameterized::TableSyntax + + let(:now) { Time.now.utc } + + subject { described_class.compute_step(start, stop) } + + where(:time_interval_in_seconds, :step) do + 0 | 60 + 10.hours | 60 + 10.hours + 1 | 61 + # frontend options + 30.minutes | 60 + 3.hours | 60 + 8.hours | 60 + 1.day | 144 + 3.days | 432 + 1.week | 1008 + end + + with_them do + let(:start) { now - time_interval_in_seconds } + let(:stop) { now } + + it { is_expected.to eq(step) } + end + end end diff --git a/spec/support/helpers/prometheus_helpers.rb b/spec/support/helpers/prometheus_helpers.rb index ce1f9fce10dd531c40850f8a0335a781d12f8732..08d1d7a605915531088f07ff12599410e8f7802c 100644 --- a/spec/support/helpers/prometheus_helpers.rb +++ b/spec/support/helpers/prometheus_helpers.rb @@ -25,12 +25,16 @@ def prometheus_query_with_time_url(prometheus_query, time) "https://prometheus.example.com/api/v1/query?#{query}" end - def prometheus_query_range_url(prometheus_query, start: 8.hours.ago, stop: Time.now.to_f) + def prometheus_query_range_url(prometheus_query, start: 8.hours.ago, stop: Time.now, step: nil) + start = start.to_f + stop = stop.to_f + step ||= Gitlab::PrometheusClient.compute_step(start, stop) + query = { query: prometheus_query, - start: start.to_f, + start: start, end: stop, - step: 1.minute.to_i + step: step }.to_query "https://prometheus.example.com/api/v1/query_range?#{query}"