whenever.rb in cron_swanson-0.2.0

- old
+ new

@@ -1,8 +1,8 @@
 module CronSwanson
   # integration for the whenever gem: https://github.com/javan/whenever
-  module Whenever
+  class Whenever
     # CronSwanson integration for whenever
     #
     # The given block can use any job types understood by your whenever configuration.
     # See https://github.com/javan/whenever#define-your-own-job-types.
     #
@@ -13,17 +13,17 @@
     # This limitation exists because I (currently) don't know of a way to inspect
     # the contents of a block at runtime. If a way to do this can be found, I
     # would prefer to calculate the time based on the block's contents.
     #
     # @example run a job once/day
-    #   # in the config/schedule.rb file
+    #   # in config/schedule.rb
     #   CronSwanson::Whenever.add(self) do
     #     rake 'job'
     #   end
     #
-    # @example run a job four times daily
-    #   # in the config/schedule.rb file
+    # @example schedule a job to four times daily
+    #   # in config/schedule.rb
     #
     #   # with ActiveSupport
     #   CronSwanson::Whenever.add(self, interval: 4.hours) do
     #     rake 'job'
     #   end
@@ -31,21 +31,63 @@
     #   # without ActiveSupport
     #   CronSwanson::Whenever.add(self, interval: 60 * 60 * 4) do
     #     rake 'job'
     #   end
     #
+    # @example run a job only on servers with a given role
+    #   # in config/schedule.rb
+    #   CronSwanson::Whenever.add(self, roles: [:app]) do
+    #     rake 'job'
+    #   end
+    #
     # @param [Whenever::JobList] whenever_job_list For code in `config/schedule.rb`
     #   this can be referred to as `self`.
-    # @param [Integer] interval how many seconds do you want between runs of this job
-    def self.add(whenever_job_list, interval: CronSwanson.default_interval, &block)
+    # @param [Integer, ActiveSupport::Duration] interval how many seconds do you want between runs
+    #   of this job
+    # @param [Array<Symbol>] roles capistrano roles that jobs in this block should be deployed to
+    def self.add(whenever_job_list, interval: CronSwanson.default_interval, roles: [], &block)
+      @whenever_jobs = []
+      @whenever_job_list = whenever_job_list
+
       if !whenever_job_list.is_a?(::Whenever::JobList)
         raise ArgumentError, "supply a Whenever::JobList. (In schedule.rb code, use `self`.)"
       end
 
       raise ArgumentError, "provide a block containing jobs to schedule." if !block_given?
 
-      # TODO: ideally we'd hash the contents of the block, not the location it was defined at
-      schedule = CronSwanson.schedule(block.source_location, interval: interval)
-      whenever_job_list.every(schedule, &Proc.new)
+      # execute the block in the context of CronSwanson::Whenever (rather than in the context
+      # of the Whenever::JobList where it will be invoked) so that we can intercept
+      # calls to `rake` and similar (via method_missing below).
+      instance_eval(&block)
+
+      # make a schedule based on the contents of the jobs which were defined in the block
+      schedule_seed = @whenever_jobs.map do |job_config|
+        m, args, _block = *job_config
+        "#{m} #{args.join}"
+      end
+      schedule = CronSwanson.schedule(schedule_seed, interval: interval)
+
+      # now that we know when to schedule the jobs, actually pass the block to Whenever
+      if roles.size > 0
+        whenever_job_list.every(schedule, roles: roles, &Proc.new)
+      else
+        whenever_job_list.every(schedule, &Proc.new)
+      end
+
+      @whenever_job_list = nil
+    end
+
+    # during .add, we accumulate calls to whenever job types
+    # this allows us to make a schedule hash from the actual jobs which are defined.
+    def self.method_missing(m, *args, &block)
+      if @whenever_job_list.nil? || @whenever_jobs.nil?
+        raise "#{self.name}.method_missing invoked outside of #{self.name}.add"
+      end
+
+      if @whenever_job_list.respond_to?(m)
+        @whenever_jobs << [m, args, block]
+      else
+        raise "#{m} is not defined. Call `job_type` to resolve this."
+      end
     end
   end
 end