Allow batch jobs to be instances

* This means we can store the arguments and settings by letting the user do `BatchJob.new(arguments).set(options)`

* Yield the batch in `enqueue` in case someone needs info from it

* When you serialize then deserialize an activejob instance, the arguments are in the serialized_arguments field and can only be transferred over by the private method `deserialize_arguments_if_needed`. This is pretty janky, so there is probably something i'm missing

* `perform_all_later` let's us do a perform_later even with instance, which does not seem to be possible on the instances themselves

app/models/solid_queue/job_batch.rb

@@ -5,6 +5,9 @@ class JobBatch < Record
     belongs_to :job, foreign_key: :job_id, optional: true
     has_many :jobs, foreign_key: :batch_id
 
+    serialize :on_finish_active_job, coder: JSON
+    serialize :on_success_active_job, coder: JSON
+
     scope :incomplete, -> {
       where(finished_at: nil).where("changed_at IS NOT NULL OR last_changed_at < ?", 1.hour.ago)
     }
@@ -21,7 +24,7 @@ def enqueue(attributes = {})
         transaction do
           job_batch = create!(batch_attributes(attributes))
           ActiveSupport::IsolatedExecutionState[:current_batch_id] = job_batch.id
-          yield
+          yield job_batch
         end
 
         job_batch
@@ -40,20 +43,22 @@ def dispatch_finished_batches
       private
 
         def batch_attributes(attributes)
-          attributes = case attributes
-          in { on_finish: on_finish_klass }
-            attributes.merge(
-              job_class: on_finish_klass,
-              completion_type: "success"
-            )
-          in { on_success: on_success_klass }
-            attributes.merge(
-              job_class: on_success_klass,
-              completion_type: "success"
-            )
+          on_finish_klass = attributes.delete(:on_finish)
+          on_success_klass = attributes.delete(:on_success)
+
+          if on_finish_klass.present?
+            attributes[:on_finish_active_job] = as_active_job(on_finish_klass).serialize
+          end
+
+          if on_success_klass.present?
+            attributes[:on_success_active_job] = as_active_job(on_success_klass).serialize
           end
 
-          attributes.except(:on_finish, :on_success)
+          attributes
+        end
+
+        def as_active_job(active_job_klass)
+          active_job_klass.is_a?(ActiveJob::Base) ? active_job_klass : active_job_klass.new
         end
     end
 
@@ -74,9 +79,10 @@ def finish
 
       attrs = {}
 
-      if job_class.present?
-        job_klass = job_class.constantize
-        active_job = job_klass.perform_later(self)
+      if on_finish_active_job.present?
+        active_job = ActiveJob::Base.deserialize(on_finish_active_job)
+        active_job.send(:deserialize_arguments_if_needed)
+        ActiveJob.perform_all_later([active_job])
         attrs[:job] = Job.find_by(active_job_id: active_job.job_id)
       end
 

db/migrate/20240131013203_create_solid_queue_batch_table.rb

@@ -2,8 +2,8 @@ class CreateSolidQueueBatchTable < ActiveRecord::Migration[7.1]
   def change
     create_table :solid_queue_job_batches do |t|
       t.references :job, index: { unique: true }
-      t.string :job_class
-      t.string :completion_type
+      t.string :on_finish_active_job
+      t.string :on_success_active_job
       t.datetime :finished_at
       t.datetime :changed_at
       t.datetime :last_changed_at

test/dummy/db/schema.rb

@@ -48,8 +48,8 @@
 
   create_table "solid_queue_job_batches", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "job_id"
-    t.string "job_class"
-    t.string "completion_type"
+    t.string "on_finish_active_job"
+    t.string "on_success_active_job"
     t.datetime "finished_at"
     t.datetime "changed_at"
     t.datetime "last_changed_at"