[DEPRECATE] no longer allow writing to ONLY cassandra for auditors

closes FOO-2045
flag=none

TEST PLAN:
  1) configure canvas to only write auditors to cassandra
  2) run canvas
  3) do auditable things (login, change course, flip flags)
  4) postgres audit logs get written anyway

Change-Id: Ide159791338a7cf5b3729c3a95a6549b1135f4ec
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/266450
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>

engines/audits/lib/audits.rb

@@ -90,7 +90,12 @@ module Audits
       # default to both for now.
       # after a year we will have hit our retention period
       # and can safely de-comission all auditors cassandra code.
-      paths.empty? ? ['cassandra', 'active_record'] : paths
+      return_paths = paths.empty? ? ['cassandra', 'active_record'] : paths
+      unless return_paths.include?('active_record')
+        logger.warn("[Auditors | DEPRECATION] Your auditors config attempts to not write to the relational db: #{paths}.  This is deprecated, the intended future target for these audit records is postgres.  Configuring to write to the db anyway.")
+        return_paths.unshift('active_record')
+      end
+      return_paths
     end
 
     def config(shard=::Switchman::Shard.current)

engines/audits/spec/audits_spec.rb

@@ -39,10 +39,10 @@ RSpec.describe Audits do
   end
 
   describe "settings parsing" do
-    it "parses pre-change write paths" do
+    it "parses pre-change write paths, but WILL NOT allow not writing to postgres" do
       inject_auditors_settings("write_paths:\n  - cassandra\nread_path: cassandra")
       expect(Audits.write_to_cassandra?).to eq(true)
-      expect(Audits.write_to_postgres?).to eq(false)
+      expect(Audits.write_to_postgres?).to eq(true)
       expect(Audits.read_from_cassandra?).to eq(true)
       expect(Audits.read_from_postgres?).to eq(false)
     end

spec/models/auditors/active_record/course_record_spec.rb

@@ -23,6 +23,10 @@ require File.expand_path(File.dirname(__FILE__) + '/../../../sharding_spec_helpe
 describe Auditors::ActiveRecord::CourseRecord do
   let(:request_id){ 'abcde-12345'}
 
+  before(:once) do
+    Auditors::ActiveRecord::Partitioner.process
+  end
+
   it "it appropriately connected to a table" do
     expect(Auditors::ActiveRecord::CourseRecord.count).to eq(0)
   end

spec/models/auditors/authentication_spec.rb

@@ -184,6 +184,12 @@ describe Auditors::Authentication do
     describe "sharding" do
       specs_require_sharding
 
+      before(:once) do
+        [Shard.current, @shard1, @shard2].each do |s|
+          s.activate{ Auditors::ActiveRecord::Partitioner.process }
+        end
+      end
+
       context "different shard, same database server" do
         before do
           @shard1.activate do

spec/models/auditors/grade_change_spec.rb

@@ -294,7 +294,7 @@ describe Auditors::GradeChange do
     end
 
     it "inserts a record" do
-      expect(Auditors::GradeChange::Stream).to receive(:insert).once
+      expect(Auditors::GradeChange::Stream).to receive(:insert).at_least(:once)
       Auditors::GradeChange.record(submission: @submission)
     end
 

spec/models/auditors_spec.rb

@@ -40,10 +40,10 @@ describe Auditors do
   end
 
   describe "settings parsing" do
-    it "parses pre-change write paths" do
+    it "parses pre-change write paths (but with deprecation forces postgres writes)" do
       inject_auditors_settings("write_paths:\n  - cassandra\nread_path: cassandra")
       expect(Auditors.write_to_cassandra?).to eq(true)
-      expect(Auditors.write_to_postgres?).to eq(false)
+      expect(Auditors.write_to_postgres?).to eq(true)
       expect(Auditors.read_from_cassandra?).to eq(true)
       expect(Auditors.read_from_postgres?).to eq(false)
     end