Sensu Handler shim for Sensu 2.0 event data. (#190)

* Added event_2to1 method to Utils and --enable-2.0-event option to base Handler class. New option makes it possible to use sensu-plugin based handlers with Sensu 2.0 events until handlers provide native 2.0 event support.

* handle case when event['client'] is nil

* Refactor event_2to1 utility function to take optional event argument

* fix bad conditional for expected integer attribute

* add test for --enable-2to1-mapping handler argument

* fix unreleased changelog entry format

* remove unneeded cornercase mapping due to now resolved attribute naming issue

* fix for handle 2to1 test

* Refactor function name from awkward 2to1 as per pr review

* return orig_event if already mapped

* fix argument to match refactor

* make it possible to set env variable to attempt v2 into v1 mapping automatically

* update changelog with more detail on added v2 -> v1 mapping support

* add support for v2 -> v1 event mapping to mutator class, and update changelog

* remove unneeded confusing unless conditional

* fix for stray comma

* refactor state to action mapping to a use a 1:1 hash lookup with a fallback if state is not in understood mapping

* refactor history handling, save original history as history_v2.

* extend 2to1 test coverage to include history

CHANGELOG.md

@@ -3,6 +3,14 @@ All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+### Added
+- Added map_v2_event_into_v1 method to Utils for all plugin classes to use. 
+- Added --map-v2-event-into-v1 runtime commandline option to base Handler and Mutator classes. 
+- Alternatively set envvar SENSU_MAP_V2_EVENT_INTO_V1=1 and handlers/mutators will automatically attempt to map 2.x event data. 
+- New cli option/envvar makes it possible to use sensu-plugin based handlers/mutators 
+  with Sensu 2.0 events until they provide native 2.0 event support internally.
+- Mapping function sets and checks for boolean event attribute 'v2_event_mapped_into_v1', 
+  to prevent mapping from running multiple times in same pipeline.
 
 ## [2.6.0] - 2018-08-28
 ### Fixed

lib/sensu-handler.rb

@@ -9,6 +9,10 @@ module Sensu
   class Handler
     include Sensu::Plugin::Utils
     include Mixlib::CLI
+    option :map_v2_event_into_v1,
+           description: 'Enable 2.x to 1.4 event mapping. Alternatively set envvar SENSU_MAP_V2_EVENT_INTO_V1=1.',
+           boolean:     true,
+           long:        '--map-v2-event-into-v1'
 
     attr_accessor :argv
 
@@ -73,6 +77,14 @@ def self.disable_autorun
       if @@autorun
         handler = @@autorun.new
         handler.read_event(STDIN)
+
+        TRUTHY_VALUES = %w[1 t true yes y].freeze
+        automap = ENV['SENSU_MAP_V2_EVENT_INTO_V1'].to_s.downcase
+
+        if handler.config[:map_v2_event_into_v1] || TRUTHY_VALUES.include?(automap)
+          new_event = handler.map_v2_event_into_v1
+          handler.event = new_event
+        end
         handler.filter
         handler.handle
       end

lib/sensu-mutator.rb

@@ -34,6 +34,10 @@ module Sensu
   class Mutator
     include Sensu::Plugin::Utils
     include Mixlib::CLI
+    option :map_v2_event_into_v1,
+           description: 'Enable 2.x to 1.4 event mapping. Alternatively set envvar SENSU_MAP_V2_EVENT_INTO_V1=1.',
+           boolean:     true,
+           long:        '--map-v2-event-into-v1'
 
     attr_accessor :argv
 
@@ -67,6 +71,15 @@ def self.disable_autorun
       return unless @@autorun
       mutator = @@autorun.new
       mutator.read_event(STDIN)
+
+      TRUTHY_VALUES = %w[1 t true yes y].freeze
+      automap = ENV['SENSU_MAP_V2_EVENT_INTO_V1'].to_s.downcase
+
+      if mutator.config[:map_v2_event_into_v1] || TRUTHY_VALUES.include?(automap)
+        new_event = mutator.map_v2_event_into_v1
+        mutator.event = new_event
+      end
+
       mutator.mutate
       mutator.dump
     end

lib/sensu-plugin/utils.rb

@@ -23,6 +23,14 @@ def settings
         @settings ||= config_files.map { |f| load_config(f) }.reduce { |a, b| deep_merge(a, b) }
       end
 
+      def event
+        @event
+      end
+
+      def event=(value)
+        @event = value
+      end
+
       def read_event(file)
         @event = ::JSON.parse(file.read)
         @event['occurrences'] ||= 1
@@ -33,6 +41,92 @@ def read_event(file)
         exit 0
       end
 
+      ##
+      #  Helper method to convert Sensu 2.0 event into Sensu 1.4 event
+      #    This is here to help keep Sensu Plugin community handlers working
+      #    until they natively support 2.0
+      #    Takes 2.0 event json object as argument
+      #    Returns event with 1.4 mapping included
+      #
+      #    Note:
+      #      The 1.4 mapping overwrites some attributes so the resulting event cannot
+      #      be used in a 2.0 workflow. The top level boolean attribute "v2_event_mapped_into_v1"
+      #      will be set to true as a hint to indicate this is a mapped event object.
+      #
+      ##
+      def map_v2_event_into_v1(orig_event = nil)
+        orig_event ||= @event
+
+        # return orig_event if already mapped
+        return orig_event if orig_event['v2_event_mapped_into_v1']
+
+        # Deep copy of orig_event
+        event = Marshal.load(Marshal.dump(orig_event))
+
+        # Trigger mapping code if enity exists and client does not
+        client_missing = event['client'].nil? || event['client'].empty?
+        if event.key?('entity') && client_missing
+          ##
+          # create the client hash from the entity hash
+          ##
+          event['client'] = event['entity']
+
+          ##
+          # Fill in missing client attributes
+          ##
+          event['client']['name']        ||= event['entity']['id']
+          event['client']['subscribers'] ||= event['entity']['subscriptions']
+
+          ##
+          # Fill in renamed check attributes expected in 1.4 event
+          #   subscribers, source
+          ##
+          event['check']['subscribers'] ||= event['check']['subscriptions']
+          event['check']['source'] ||= event['check']['proxy_entity_id']
+
+          ##
+          # Mimic 1.4 event action based on 2.0 event state
+          #  action used in logs and fluentd plugins handlers
+          ##
+          action_state_mapping = {
+            'flapping' => 'flapping',
+            'passing' => 'resolve',
+            'failing' => 'create'
+          }
+
+          state = event['check']['state'] || 'unknown::2.0_event'
+
+          # Attempt to map 2.0 event state to 1.4 event action
+          event['action'] ||= action_state_mapping[state.downcase]
+          # Fallback action is 2.0 event state
+          event['action'] ||= state
+
+          ##
+          # Mimic 1.4 event history based on 2.0 event history
+          #  Note: This overwrites the same history attribute
+          #    2.x history is an array of hashes, each hash includes status
+          #    1.x history is an array of statuses
+          ##
+          if event['check']['history']
+            # Let's save the original history
+            history_v2 = Marshal.load(Marshal.dump(event['check']['history']))
+            event['check']['history_v2'] = history_v2
+            legacy_history = []
+            event['check']['history'].each do |h|
+              legacy_history << h['status'].to_i.to_s || '3'
+            end
+            event['check']['history'] = legacy_history
+          end
+
+          ##
+          # Setting flag indicating this function has already been called
+          ##
+          event['v2_event_mapped_into_v1'] = true
+        end
+        # return the updated event
+        event
+      end
+
       def net_http_req_class(method)
         case method.to_s.upcase
         when 'GET'

test/external/handle-2to1

@@ -0,0 +1,33 @@
+#!/usr/bin/env ruby
+require 'sensu-handler'
+
+class Helpers < Sensu::Handler
+  def handle
+    puts event_summary
+  end
+
+  def api_request(*_args)
+    nil
+  end
+
+  def stash_exists?(*_args)
+    nil
+  end
+
+  def event_exists?(*_args)
+    true
+  end
+
+  def event_summary
+    client_name = @event['client']['name']
+    check_name = @event['check']['name']
+    source = @event['check']['source']
+    output = @event['check']['output']
+    total_state_change = @event['check']['total_state_change']
+    action = @event['action']
+    client_subscribers = @event['client']['subscribers'].join('|')
+    check_subscribers = @event['client']['subscribers'].join('^')
+    history = @event['check']['history'].join('')
+    [client_name, check_name, source, output, total_state_change, action, client_subscribers, check_subscribers, history].join(' : ')
+  end
+end

test/fixtures/basic_v2_event.json

@@ -0,0 +1 @@
+{"entity":{"id":"test_entity","subscriptions":["sub1","sub2","sub3"]},"check":{"name":"test_check","output":"test_output","subscriptions":["sub1","sub2","sub3"],"proxy_entity_id":"test_proxy","total_state_change":4,"state":"failing","history":[{"status":0,"executed":0},{"status":1,"executed":1},{"status":2,"executed":2},{"status":3,"executed":3},{"status":0,"executed":4}],"status":0}}

test/handle_2to1_test.rb

@@ -0,0 +1,18 @@
+require 'test_helper'
+require 'English'
+
+class TestHandle2to1 < MiniTest::Test
+  include SensuPluginTestHelper
+
+  def setup
+    set_script 'external/handle-2to1 --map-v2-event-into-v1'
+  end
+
+  def test_2to1_enabled
+    event = JSON.parse(fixture('basic_v2_event.json').read)
+    expected = "test_entity : test_check : test_proxy : test_output : 4 : create : sub1|sub2|sub3 : sub1^sub2^sub3 : 01230\n"
+    output = run_script_with_input(JSON.generate(event))
+    assert_equal(0, $CHILD_STATUS.exitstatus)
+    assert_match(expected, output)
+  end
+end

test/mutator_2to1_test.rb

@@ -0,0 +1,24 @@
+#!/usr/bin/env ruby
+require 'English'
+
+require 'test_helper'
+
+# Simple Heper to test mutator
+class TestMutatorHelpers < MiniTest::Test
+  include SensuPluginTestHelper
+  def test_base_2to1_mutator
+    set_script 'external/mutator-trivial --map-v2-event-into-v1'
+    event = JSON.parse(fixture('basic_v2_event.json').read)
+    output = run_script_with_input(JSON.generate(event))
+    assert_equal(0, $CHILD_STATUS.exitstatus)
+    assert_equal(event['entity']['id'], JSON.parse(output)['client']['name'])
+  end
+
+  def test_external_2to1_mutator
+    set_script 'external/mutator-helpers --map-v2-event-into-v1'
+    event = JSON.parse(fixture('basic_v2_event.json').read)
+    output = run_script_with_input(JSON.generate(event))
+    assert_equal(0, $CHILD_STATUS.exitstatus)
+    assert_equal(true, JSON.parse(output)['mutated'])
+  end
+end