debian-mirror-gitlab/lib/grafana/validator.rb
2020-04-08 14:13:33 +05:30

96 lines
2.7 KiB
Ruby

# frozen_string_literal: true
# Performs checks on whether resources from Grafana can be handled
# We have certain restrictions on which formats we accept.
# Some are technical requirements, others are simplifications.
module Grafana
class Validator
Error = Class.new(StandardError)
attr_reader :grafana_dashboard, :datasource, :panel, :query_params
UNSUPPORTED_GRAFANA_GLOBAL_VARS = %w(
$__interval_ms
$__timeFilter
$__name
$timeFilter
$interval
).freeze
def initialize(grafana_dashboard, datasource, panel, query_params)
@grafana_dashboard = grafana_dashboard
@datasource = datasource
@panel = panel
@query_params = query_params
end
def validate!
validate_query_params!
validate_panel_type!
validate_variable_definitions!
validate_global_variables!
validate_datasource! if datasource
end
def valid?
validate!
true
rescue ::Grafana::Validator::Error
false
end
private
# See defaults in Banzai::Filter::InlineGrafanaMetricsFilter.
def validate_query_params!
return if [:from, :to].all? { |param| query_params.include?(param) }
raise_error 'Grafana query parameters must include from and to.'
end
# We may choose to support other panel types in future.
def validate_panel_type!
return if panel && panel[:type] == 'graph' && panel[:lines]
raise_error 'Panel type must be a line graph.'
end
# We must require variable definitions to create valid prometheus queries.
def validate_variable_definitions!
return unless grafana_dashboard[:dashboard][:templating]
return if grafana_dashboard[:dashboard][:templating][:list].all? do |variable|
query_params[:"var-#{variable[:name]}"].present?
end
raise_error 'All Grafana variables must be defined in the query parameters.'
end
# We may choose to support further Grafana variables in future.
def validate_global_variables!
return unless panel_contains_unsupported_vars?
raise_error "Prometheus must not include #{UNSUPPORTED_GRAFANA_GLOBAL_VARS}"
end
# We may choose to support additional datasources in future.
def validate_datasource!
return if datasource[:access] == 'proxy' && datasource[:type] == 'prometheus'
raise_error 'Only Prometheus datasources with proxy access in Grafana are supported.'
end
def panel_contains_unsupported_vars?
panel[:targets].any? do |target|
UNSUPPORTED_GRAFANA_GLOBAL_VARS.any? do |variable|
target[:expr].include?(variable)
end
end
end
def raise_error(message)
raise Validator::Error, message
end
end
end