Improve migrations using triggerscheck-trigger-permissions-mysql

This adds a bunch of checks to migrations that may create or drop
triggers. Dropping triggers/functions is done using "IF EXISTS" so we
don't throw an error if the object in question has already been dropped.
We now also raise a custom error (message) when the user does not have
TRIGGER privileges. This should prevent the schema from entering an
inconsistent state while also providing the user with enough information
on how to solve the problem.

The recommendation of using SUPERUSER permissions is a bit extreme but
we require this anyway (Omnibus also configures users with this
permission).

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/36633

1 files changed, 30 insertions, 0 deletions

diff --git a/spec/lib/gitlab/database/grant_spec.rb b/spec/lib/gitlab/database/grant_spec.rb
new file mode 100644
index 00000000000..651da3e8476
--- /dev/null
+++ b/spec/lib/gitlab/database/grant_spec.rb
@@ -0,0 +1,30 @@
+require 'spec_helper'
+
+describe Gitlab::Database::Grant do
+  describe '.scope_to_current_user' do
+    it 'scopes the relation to the current user' do
+      user = Gitlab::Database.username
+      column = Gitlab::Database.postgresql? ? :grantee : :User
+      names = described_class.scope_to_current_user.pluck(column).uniq
+
+      expect(names).to eq([user])
+    end
+  end
+
+  describe '.create_and_execute_trigger' do
+    it 'returns true when the user can create and execute a trigger' do
+      # We assume the DB/user is set up correctly so that triggers can be
+      # created, which is necessary anyway for other tests to work.
+      expect(described_class.create_and_execute_trigger?('users')).to eq(true)
+    end
+
+    it 'returns false when the user can not create and/or execute a trigger' do
+      allow(described_class).to receive(:scope_to_current_user)
+        .and_return(described_class.none)
+
+      result = described_class.create_and_execute_trigger?('kittens')
+
+      expect(result).to eq(false)
+    end
+  end
+end