146 lines
3.9 KiB
Ruby
146 lines
3.9 KiB
Ruby
# frozen_string_literal: true
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module Prometheus
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class ProxyService < BaseService
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include ReactiveCaching
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include Gitlab::Utils::StrongMemoize
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self.reactive_cache_key = ->(service) { [] }
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self.reactive_cache_lease_timeout = 30.seconds
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# reactive_cache_refresh_interval should be set to a value higher than
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# reactive_cache_lifetime. If the refresh_interval is less than lifetime
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# then the ReactiveCachingWorker will re-query prometheus for this
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# PromQL query even though it's (probably) already been picked up by
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# the frontend
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# refresh_interval should be set less than lifetime only if this data
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# is expected to change *and* be fetched again by the frontend
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self.reactive_cache_refresh_interval = 90.seconds
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self.reactive_cache_lifetime = 1.minute
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self.reactive_cache_work_type = :external_dependency
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self.reactive_cache_worker_finder = ->(_id, *args) { from_cache(*args) }
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attr_accessor :proxyable, :method, :path, :params
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PROMETHEUS_QUERY_API = 'query'
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PROMETHEUS_QUERY_RANGE_API = 'query_range'
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PROMETHEUS_SERIES_API = 'series'
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PROXY_SUPPORT = {
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PROMETHEUS_QUERY_API => {
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method: ['GET'],
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params: %w(query time timeout)
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},
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PROMETHEUS_QUERY_RANGE_API => {
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method: ['GET'],
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params: %w(query start end step timeout)
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},
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PROMETHEUS_SERIES_API => {
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method: %w(GET),
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params: %w(match start end)
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}
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}.freeze
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def self.from_cache(proxyable_class_name, proxyable_id, method, path, params)
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proxyable_class = begin
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proxyable_class_name.constantize
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rescue NameError
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nil
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end
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return unless proxyable_class
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proxyable = proxyable_class.find(proxyable_id)
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new(proxyable, method, path, params)
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end
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# proxyable can be any model which responds to .prometheus_adapter
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# like Environment.
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def initialize(proxyable, method, path, params)
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@proxyable = proxyable
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@path = path
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# Convert ActionController::Parameters to hash because reactive_cache_worker
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# does not play nice with ActionController::Parameters.
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@params = filter_params(params, path).to_hash
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@method = method
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end
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def id
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nil
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end
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def execute
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return cannot_proxy_response unless can_proxy?
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return no_prometheus_response unless can_query?
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with_reactive_cache(*cache_key) do |result|
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result
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end
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end
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def calculate_reactive_cache(proxyable_class_name, proxyable_id, method, path, params)
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return no_prometheus_response unless can_query?
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response = prometheus_client_wrapper.proxy(path, params)
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success(http_status: response.code, body: response.body)
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rescue Gitlab::PrometheusClient::Error => err
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service_unavailable_response(err)
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end
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def cache_key
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[@proxyable.class.name, @proxyable.id, @method, @path, @params]
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end
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private
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def service_unavailable_response(exception)
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error(exception.message, :service_unavailable)
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end
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def no_prometheus_response
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error('No prometheus server found', :service_unavailable)
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end
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def cannot_proxy_response
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error('Proxy support for this API is not available currently')
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end
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def prometheus_adapter
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strong_memoize(:prometheus_adapter) do
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@proxyable.prometheus_adapter
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end
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end
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def prometheus_client_wrapper
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prometheus_adapter&.prometheus_client
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end
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def can_query?
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prometheus_adapter&.can_query?
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end
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def filter_params(params, path)
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params = substitute_params(params)
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params.slice(*PROXY_SUPPORT.dig(path, :params))
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end
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def can_proxy?
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PROXY_SUPPORT.dig(@path, :method)&.include?(@method)
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end
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def substitute_params(params)
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start_time = params[:start_time]
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end_time = params[:end_time]
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params['start'] = start_time if start_time
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params['end'] = end_time if end_time
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params
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end
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end
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end
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