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|
# frozen_string_literal: true
module Prometheus
class ProxyService < BaseService
include ReactiveCaching
include Gitlab::Utils::StrongMemoize
self.reactive_cache_key = ->(service) { service.cache_key }
self.reactive_cache_lease_timeout = 30.seconds
self.reactive_cache_refresh_interval = 30.seconds
self.reactive_cache_lifetime = 1.minute
self.reactive_cache_worker_finder = ->(_id, *args) { from_cache(*args) }
attr_accessor :proxyable, :method, :path, :params
PROXY_SUPPORT = {
'query' => {
method: ['GET'],
params: %w(query time timeout)
},
'query_range' => {
method: ['GET'],
params: %w(query start end step timeout)
}
}.freeze
def self.from_cache(proxyable_class_name, proxyable_id, method, path, params)
proxyable_class = begin
proxyable_class_name.constantize
rescue NameError
nil
end
return unless proxyable_class
proxyable = proxyable_class.find(proxyable_id)
new(proxyable, method, path, params)
end
# proxyable can be any model which responds to .prometheus_adapter
# like Environment.
def initialize(proxyable, method, path, params)
@proxyable = proxyable
@path = path
# Convert ActionController::Parameters to hash because reactive_cache_worker
# does not play nice with ActionController::Parameters.
@params = filter_params(params, path).to_hash
@method = method
end
def id
nil
end
def execute
return cannot_proxy_response unless can_proxy?
return no_prometheus_response unless can_query?
with_reactive_cache(*cache_key) do |result|
result
end
end
def calculate_reactive_cache(proxyable_class_name, proxyable_id, method, path, params)
return no_prometheus_response unless can_query?
response = prometheus_client_wrapper.proxy(path, params)
success(http_status: response.code, body: response.body)
rescue Gitlab::PrometheusClient::Error => err
service_unavailable_response(err)
end
def cache_key
[@proxyable.class.name, @proxyable.id, @method, @path, @params]
end
private
def service_unavailable_response(exception)
error(exception.message, :service_unavailable)
end
def no_prometheus_response
error('No prometheus server found', :service_unavailable)
end
def cannot_proxy_response
error('Proxy support for this API is not available currently')
end
def prometheus_adapter
strong_memoize(:prometheus_adapter) do
@proxyable.prometheus_adapter
end
end
def prometheus_client_wrapper
prometheus_adapter&.prometheus_client
end
def can_query?
prometheus_adapter&.can_query?
end
def filter_params(params, path)
params.slice(*PROXY_SUPPORT.dig(path, :params))
end
def can_proxy?
PROXY_SUPPORT.dig(@path, :method)&.include?(@method)
end
end
end
|
