Completely remove old non-structured errors and migrate existing ones.

db/migrate/20181129093207_drop_errors.rb

@@ -0,0 +1,46 @@
+class DropErrors < ActiveRecord::Migration[5.2]
+
+  # define old CodeOcean::Error module so that the migration works
+  module CodeOcean
+    class Error < ApplicationRecord
+      belongs_to :execution_environment
+
+      scope :for_execution_environment, ->(execution_environment) { where(execution_environment_id: execution_environment.id) }
+      scope :grouped_by_message, -> { select('MAX(created_at) AS created_at, MAX(id) AS id, message, COUNT(id) AS count').group(:message).order('count DESC') }
+
+      validates :execution_environment_id, presence: true
+      validates :message, presence: true
+
+      def self.nested_resource?
+        true
+      end
+
+      def to_s
+        id.to_s
+      end
+    end
+  end
+
+
+
+  def change
+
+    puts 'Migrating CodeOcean::Errors to StructuredErrors using RegEx. This might take a (long) while but will return.'
+    submissions_controller = SubmissionsController.new
+
+    # Iterate only over those Errors containing a message and submission_id
+    CodeOcean::Error.where.not(message: [nil, ""]).where.not(submission_id: [nil, ""]).each do |error|
+      raw_output = error.message
+      submission = Submission.find_by(id: error.submission_id)
+
+      # Validate that we have everything we need: the output, the submission and the execution environment
+      next if submission.exercise.execution_environment.blank?
+
+      submissions_controller.instance_variable_set(:@raw_output, raw_output)
+      submissions_controller.instance_variable_set(:@submission, submission)
+      submissions_controller.extract_errors
+    end
+
+    drop_table :errors
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_11_27_160857) do
+ActiveRecord::Schema.define(version: 2018_11_29_093207) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -81,15 +81,6 @@ ActiveRecord::Schema.define(version: 2018_11_27_160857) do
     t.text "hint"
   end
 
-  create_table "errors", force: :cascade do |t|
-    t.integer "execution_environment_id"
-    t.text "message"
-    t.datetime "created_at"
-    t.datetime "updated_at"
-    t.integer "submission_id"
-    t.index ["submission_id"], name: "index_errors_on_submission_id"
-  end
-
   create_table "events", force: :cascade do |t|
     t.string "category"
     t.string "data"

db/seeds/development.rb

@@ -10,9 +10,6 @@ Rails.application.routes.default_url_options = Rails.application.config.action_m
 # execution environments
 ExecutionEnvironment.create_factories
 
-# errors
-CodeOcean::Error.create_factories
-
 # exercises
 @exercises = find_factories_by_class(Exercise).map(&:name).map { |factory_name| [factory_name, FactoryBot.create(factory_name)] }.to_h