added service_status module

app/services/db/update_db.rb

@@ -2,12 +2,11 @@
 
 # Handles construction of database objects
 class UpdateDb
-  attr_accessor :warnings, :errors
+  include ServiceStatus
 
   def initialize(db:)
     @db = db
-    @warnings = []
-    @errors = []
+    super()
   end
 
   def run(db_adapter:)
@@ -19,16 +18,10 @@ class UpdateDb
     entries = __create_entries(db_adapter.schema)
 
     updater = UpdateFolder.new(@root_folder, entries)
-    updater.run
-    @errors << updater.errors
-    @warnings << updater.warnings
-
-    # parse the entries array
-    # Note: @root_folder gets linked in on
-    #       the first call to __build_folder
-    # Don't save the result if there were errors
-    return false unless @errors.empty?
+    absorb_status(updater.run)
+
     @db.save
+    self
   end
 
   protected

app/services/db_file/update_file.rb

@@ -2,18 +2,18 @@
 
 # Handles construction of DbFolder objects
 class UpdateFile
-  attr_accessor :warnings, :errors
+  include ServiceStatus
 
   def initialize(file, base_entry, decimation_entries)
     @file = file
     @base_entry = base_entry
     @decimation_entries = decimation_entries
-    @warnings = []
-    @errors = []
+    super()
   end
 
   def run
     __update_file(@file, @base_entry, @decimation_entries)
+    self
   end
 
   # regex matching the ~decimXX ending on a stream path

app/services/db_folder/update_folder.rb

@@ -2,13 +2,12 @@
 
 # Handles construction of DbFolder objects
 class UpdateFolder
-  attr_accessor :warnings, :errors
+  include ServiceStatus
 
   def initialize(folder, entries)
     @folder = folder
     @entries = entries
-    @warnings = []
-    @errors = []
+    super()
   end
 
   # returns the updated DbFolder object
@@ -21,6 +20,7 @@ class UpdateFolder
     __parse_folder_entries(@folder, @entries)
     # save the result
     @folder.save!
+    self
   end
 
   protected
@@ -85,9 +85,7 @@ class UpdateFolder
       else # its a folder
         updater = __build_folder(folder, entry_group, name)
       end
-      updater.run
-      @warnings << updater.warnings
-      @errors << updater.errors
+      absorb_status(updater.run)
     end
   end
 

app/services/nilm/create_nilm.rb

@@ -9,7 +9,7 @@ class CreateNilm
     @warnings = []
   end
 
-  def build(name:, url:, description: '')
+  def run(name:, url:, description: '')
     # create the NILM object
     @nilm = Nilm.new(name: name, url: url,
                      description: description)

app/services/service_status.rb

+# frozen_string_literal: true
+
+# Handles service errors and warnings. Design pattern:
+# All service action should occur in the run() function
+# Within run, call add_error or add_warning with string
+# messages. At the end of run() return the service object itself
+# For nested services, call absorb_service(child.run()) to nest
+# the errors and warnings of the child into the parent, set
+# the action parameter to NEVER_FAIL, FAIL_ON_WARNING, or
+# FAIL_ON_ERROR to determine when (if ever), absorb_status
+# returns false
+module ServiceStatus
+  attr_reader :errors, :warnings
+
+  FAIL_ON_ERROR   = 0
+  FAIL_ON_WARNING = 1
+  NEVER_FAIL      = 2
+
+  def initialize
+    @errors = []
+    @warnings = []
+  end
+
+  def add_error(message)
+    @errors << String(message)
+  end
+
+  def errors?
+    !@errors.empty?
+  end
+
+  def add_warning(message)
+    @warnings << String(message)
+  end
+
+  def warnings?
+    !@warnings.empty?
+  end
+
+  def run
+    raise 'Implement in client, return service object'
+  end
+
+  def absorb_status(service, action: FAIL_ON_ERROR)
+    @warnings += service.warnings
+    @errors += service.errors
+    case action
+    when FAIL_ON_WARNING
+      return false if warnings? || errors?
+    when FAIL_ON_ERROR
+      return false if errors?
+    end
+    true
+  end
+end

spec/services/nilm/create_nilm_spec.rb

@@ -11,7 +11,7 @@ RSpec.describe 'CreateNilm' do
       allow(UpdateDb).to receive(:new).and_return(service)
       # run the NILM creation
       nilm_creator = CreateNilm.new
-      nilm_creator.build(name: 'test', url: test_nilm_url)
+      nilm_creator.run(name: 'test', url: test_nilm_url)
       # verify NILM components are present
       expect(nilm_creator.nilm).to be_present
       expect(nilm_creator.nilm.db).to be_present

spec/services/service_status_spec.rb

+# frozen_string_literal: true
+
+require 'rails_helper'
+
+class ModuleTester
+  include ServiceStatus
+
+  def initialize
+    @x = 2
+    super
+  end
+end
+
+describe 'ServiceStatus' do
+  it 'tracks errors' do
+    x = ModuleTester.new
+    x.add_error('message')
+    expect(x.errors?).to be true
+    expect(x.errors.length).to eq(1)
+  end
+
+  it 'tracks warnings' do
+    x = ModuleTester.new
+    x.add_warning('message')
+    expect(x.warnings?).to be true
+    expect(x.warnings.length).to eq(1)
+  end
+
+  it 'raises error if *run* is not implemented' do
+    x = ModuleTester.new
+    expect { x.run }.to raise_error(RuntimeError)
+  end
+
+  describe 'absorb_status' do
+    let(:parent) { ModuleTester.new }
+    let(:child) { ModuleTester.new }
+
+    it 'adds errors/warnings from service into itself' do
+      child.add_error('test')
+      child.add_warning('test')
+      parent.absorb_status(child)
+      expect(parent.errors?).to be true
+      expect(parent.warnings?).to be true
+    end
+    it 'it always returns true if action==NEVER_FAIL' do
+      child.add_error('test')
+      child.add_warning('test')
+      expect(
+        parent.absorb_status(child,
+                             action: ServiceStatus::NEVER_FAIL))
+        .to be true
+    end
+
+    it 'fails on errors and warnings with FAIL_ON_WARNING' do
+      child.add_warning('test')
+      expect(
+        parent.absorb_status(child,
+                             action: ServiceStatus::FAIL_ON_WARNING))
+        .to be false
+    end
+    it 'fails on errors with FAIL_ON_ERROR' do
+      child.add_error('test')
+      # default action
+      expect(parent.absorb_status(child)).to be false
+    end
+  end
+end