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|
# frozen_string_literal: true
module Prometheus
class ProxyVariableSubstitutionService < BaseService
include Stepable
VARIABLE_INTERPOLATION_REGEX = /
{{ # Variable needs to be wrapped in these chars.
\s* # Allow whitespace before and after the variable name.
(?<variable> # Named capture.
\w+ # Match one or more word characters.
)
\s*
}}
/x.freeze
steps :validate_variables,
:add_params_to_result,
:substitute_params,
:substitute_variables
def initialize(environment, params = {})
@environment, @params = environment, params.deep_dup
end
def execute
execute_steps
end
private
def validate_variables(_result)
return success unless variables
unless variables.is_a?(ActionController::Parameters)
return error(_('Optional parameter "variables" must be a Hash. Ex: variables[key1]=value1'))
end
success
end
def add_params_to_result(result)
result[:params] = params
success(result)
end
def substitute_params(result)
start_time = result[:params][:start_time]
end_time = result[:params][:end_time]
result[:params][:start] = start_time if start_time
result[:params][:end] = end_time if end_time
success(result)
end
def substitute_variables(result)
return success(result) unless query(result)
result[:params][:query] = gsub(query(result), full_context)
success(result)
end
def gsub(string, context)
# Search for variables of the form `{{variable}}` in the string and replace
# them with their value.
string.gsub(VARIABLE_INTERPOLATION_REGEX) do |match|
# Replace with the value of the variable, or if there is no such variable,
# replace the invalid variable with itself. So,
# `up{instance="{{invalid_variable}}"}` will remain
# `up{instance="{{invalid_variable}}"}` after substitution.
context.fetch($~[:variable], match)
end
end
def predefined_context
Gitlab::Prometheus::QueryVariables.call(@environment).stringify_keys
end
def full_context
@full_context ||= predefined_context.reverse_merge(variables_hash)
end
def variables
params[:variables]
end
def variables_hash
variables.to_h
end
def query(result)
result[:params][:query]
end
end
end
|
