Fix: compatibility with all (>= 3.0) rufus-scheduler versions (#97)

.travis.yml

@@ -1,2 +1,7 @@
 import:
-- logstash-plugins/.ci:travis/[email protected]
+  - logstash-plugins/.ci:travis/[email protected]
+
+env:
+  jobs: # test with old scheduler version (3.0 was locked in LS 7.x)
+    - ELASTIC_STACK_VERSION=7.x RUFUS_SCHEDULER_VERSION=3.0.9
+    - ELASTIC_STACK_VERSION=6.x RUFUS_SCHEDULER_VERSION=3.0.9

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 5.2.4
+  - Fix: compatibility with all (>= 3.0) rufus-scheduler versions [#97](https://github.com/logstash-plugins/logstash-integration-jdbc/pull/97) 
+
 ## 5.2.3
   - Performance: avoid contention on scheduler execution [#103](https://github.com/logstash-plugins/logstash-integration-jdbc/pull/103)
 

Gemfile

@@ -9,3 +9,5 @@ if Dir.exist?(logstash_path) && use_logstash_source
   gem 'logstash-core', :path => "#{logstash_path}/logstash-core"
   gem 'logstash-core-plugin-api', :path => "#{logstash_path}/logstash-core-plugin-api"
 end
+
+gem 'rufus-scheduler', ENV['RUFUS_SCHEDULER_VERSION'] if ENV['RUFUS_SCHEDULER_VERSION']

lib/logstash/filters/jdbc/loader_schedule.rb

@@ -4,60 +4,26 @@
 
 module LogStash module Filters module Jdbc
   class LoaderSchedule < Validatable
-    attr_reader :schedule_frequency, :loader_schedule
-
-    def to_log_string
-      message = ""
-      message.concat "these months in the year [#{@cronline.months.to_a.join(", ")}];" unless @cronline.months.nil?
-      message.concat "these days in the month [#{@cronline.days.to_a.join(", ")}];" unless @cronline.days.nil?
-      message.concat "these hours in the day [#{@cronline.hours.to_a.join(", ")}];" unless @cronline.hours.nil?
-      message.concat "these minutes in the hour [#{@cronline.minutes.to_a.join(", ")}];" unless @cronline.minutes.nil?
-      message.concat "these seconds in the minute [#{@cronline.seconds.to_a.join(", ")}]" unless @cronline.seconds.nil?
-      if !message.empty?
-        message.prepend "Scheduled for: "
-      end
-      message
-    end
+    attr_reader :loader_schedule
 
     private
 
-    def post_initialize
-      if valid?
-        # From the Rufus::Scheduler docs:
-        #   By default, rufus-scheduler sleeps 0.300 second between every step.
-        #   At each step it checks for jobs to trigger and so on.
-        # set the frequency to 2.5 seconds if we are not reloading in the seconds timeframe
-        # rufus scheduler thread should respond to stop quickly enough.
-        if only_seconds_set?
-          @schedule_frequency = 0.3
-        else
-          @schedule_frequency = 2.5
-        end
-      end
-    end
-
-
-    def only_seconds_set?
-      @cronline.seconds &&
-        @cronline.minutes.nil? &&
-        @cronline.hours.nil? &&
-        @cronline.days.nil? &&
-        @cronline.months.nil?
-    end
-
+    # @overload
     def parse_options
       @loader_schedule = @options
 
-      unless @loader_schedule.is_a?(String)
+      if @loader_schedule.is_a?(String)
+        begin
+          # Rufus::Scheduler 3.0 - 3.6 methods signature: parse_cron(o, opts)
+          # since Rufus::Scheduler 3.7 methods signature: parse_cron(o, opts={})
+          @cronline = Rufus::Scheduler.parse_cron(@loader_schedule, {})
+        rescue => e
+          @option_errors << "The loader_schedule option is invalid: #{e.message}"
+        end
+      else
         @option_errors << "The loader_schedule option must be a string"
       end
 
-      begin
-        @cronline = Rufus::Scheduler::CronLine.new(@loader_schedule)
-      rescue => e
-        @option_errors << "The loader_schedule option is invalid: #{e.message}"
-      end
-
       @valid = @option_errors.empty?
     end
   end

lib/logstash/filters/jdbc/repeating_load_runner.rb

@@ -3,8 +3,6 @@
 
 module LogStash module Filters module Jdbc
   class RepeatingLoadRunner < SingleLoadRunner
-   # info - attr_reader :local, :loaders, :preloaders
-
     def repeated_load
       local.repopulate_all(loaders)
       @reload_counter.increment

lib/logstash/filters/jdbc/single_load_runner.rb

@@ -26,10 +26,6 @@ def initial_load
     def repeated_load
     end
 
-    def call
-      repeated_load
-    end
-
     def reload_count
       @reload_counter.value
     end

lib/logstash/filters/jdbc_static.rb

@@ -3,6 +3,7 @@
 require "logstash/filters/base"
 require "logstash/namespace"
 require "logstash/plugin_mixins/ecs_compatibility_support"
+require "logstash/plugin_mixins/jdbc/scheduler"
 require_relative "jdbc/loader"
 require_relative "jdbc/loader_schedule"
 require_relative "jdbc/repeating_load_runner"
@@ -191,17 +192,15 @@ def prepare_runner
     @processor = Jdbc::LookupProcessor.new(@local_lookups, global_lookup_options)
     runner_args.unshift(@processor.local)
     if @loader_schedule
-      args = []
       @loader_runner = Jdbc::RepeatingLoadRunner.new(*runner_args)
       @loader_runner.initial_load
-      cronline = Jdbc::LoaderSchedule.new(@loader_schedule)
-      cronline.to_log_string.tap do |msg|
-        logger.info("Scheduler operations: #{msg}") unless msg.empty?
+      @scheduler = LogStash::PluginMixins::Jdbc::Scheduler.
+          start_cron_scheduler(@loader_schedule, thread_name: "[#{id}]-jdbc_static__scheduler") { @loader_runner.repeated_load }
+      cron_job = @scheduler.cron_jobs.first
+      if cron_job
+        frequency = cron_job.respond_to?(:rough_frequency) ? cron_job.rough_frequency : cron_job.frequency
+        logger.info("Loaders will execute every #{frequency} seconds", loader_schedule: @loader_schedule)
       end
-      logger.info("Scheduler scan for work frequency is: #{cronline.schedule_frequency}")
-      rufus_args = {:max_work_threads => 1, :frequency => cronline.schedule_frequency}
-      @scheduler = Rufus::Scheduler.new(rufus_args)
-      @scheduler.cron(cronline.loader_schedule, @loader_runner)
     else
       @loader_runner = Jdbc::SingleLoadRunner.new(*runner_args)
       @loader_runner.initial_load

lib/logstash/inputs/jdbc.rb

@@ -295,19 +295,8 @@ def run(queue)
     load_driver
     if @schedule
       # input thread (Java) name example "[my-oracle]<jdbc"
-      @scheduler = LogStash::PluginMixins::Jdbc::Scheduler.new(
-          :max_work_threads => 1,
-          :thread_name => "[#{id}]<jdbc__scheduler",
-          # amount the scheduler thread sleeps between checking whether jobs
-          # should trigger, default is 0.3 which is a bit too often ...
-          # in theory the cron expression '* * * * * *' supports running jobs
-          # every second but this is very rare, we could potentially go higher
-          :frequency => 1.0,
-      )
-      @scheduler.schedule_cron @schedule do
-        execute_query(queue)
-      end
-
+      @scheduler = LogStash::PluginMixins::Jdbc::Scheduler.
+          start_cron_scheduler(@schedule, thread_name: "[#{id}]<jdbc__scheduler") { execute_query(queue) }
       @scheduler.join
     else
       execute_query(queue)

lib/logstash/plugin_mixins/jdbc/scheduler.rb

@@ -12,6 +12,34 @@ class Scheduler < Rufus::Scheduler
     TimeImpl = defined?(Rufus::Scheduler::EoTime) ? Rufus::Scheduler::EoTime :
                    (defined?(Rufus::Scheduler::ZoTime) ? Rufus::Scheduler::ZoTime : ::Time)
 
+    # @param cron [String] cron-line
+    # @param opts [Hash] scheduler options
+    # @return scheduler instance
+    def self.start_cron_scheduler(cron, opts = {}, &block)
+      unless block_given?
+        raise ArgumentError, 'missing (cron scheduler) block - worker task to execute'
+      end
+      scheduler = new_scheduler(opts)
+      scheduler.schedule_cron(cron, &block)
+      scheduler
+    end
+
+    # @param opts [Hash] scheduler options
+    # @return scheduler instance
+    def self.new_scheduler(opts)
+      unless opts.key?(:thread_name)
+        raise ArgumentError, 'thread_name: option is required to be able to distinguish multiple scheduler threads'
+      end
+      opts[:max_work_threads] ||= 1
+      # amount the scheduler thread sleeps between checking whether jobs
+      # should trigger, default is 0.3 which is a bit too often ...
+      # in theory the cron expression '* * * * * *' supports running jobs
+      # every second but this is very rare, we could potentially go higher
+      opts[:frequency] ||= 1.0
+
+      new(opts)
+    end
+
     # @overload
     def timeout_jobs
       # Rufus relies on `Thread.list` which is a blocking operation and with many schedulers

logstash-integration-jdbc.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name = 'logstash-integration-jdbc'
-  s.version         = '5.2.3'
+  s.version         = '5.2.4'
   s.licenses = ['Apache License (2.0)']
   s.summary         = "Integration with JDBC - input and filter plugins"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"
@@ -34,7 +34,9 @@ Gem::Specification.new do |s|
 
   s.add_runtime_dependency 'tzinfo'
   s.add_runtime_dependency 'tzinfo-data'
-  s.add_runtime_dependency 'rufus-scheduler', '~> 3.0.9'
+  # plugin maintains compatibility with < 3.5 (3.0.9)
+  # but works with newer rufus-scheduler >= 3.5 as well
+  s.add_runtime_dependency 'rufus-scheduler'
   s.add_runtime_dependency 'logstash-mixin-ecs_compatibility_support', '~>1.3'
   s.add_runtime_dependency "logstash-mixin-validator_support", '~> 1.0'
   s.add_runtime_dependency "logstash-mixin-event_support", '~> 1.0'

spec/filters/jdbc/repeating_load_runner_spec.rb

@@ -17,7 +17,7 @@ module LogStash module Filters module Jdbc
         expect(local_db).to receive(:populate_all).once.with(loaders)
         expect(local_db).to receive(:repopulate_all).once.with(loaders)
         runner.initial_load
-        subject.call
+        subject.repeated_load
       end
     end
   end