Implement migration strategy for token authenticatable

app/models/concerns/token_authenticatable_strategies/base.rb

@@ -47,6 +47,14 @@ module TokenAuthenticatableStrategies
       options[:fallback] == true
     end
 
+    def migrating?
+      unless options[:migrating].in?([true, false, nil])
+        raise ArgumentError, 'migrating: needs to be a boolean value!'
+      end
+
+      options[:migrating] == true
+    end
+
     def self.fabricate(model, field, options)
       if options[:digest] && options[:encrypted]
         raise ArgumentError, 'Incompatible options set!'

app/models/concerns/token_authenticatable_strategies/encrypted.rb

@@ -2,14 +2,24 @@
 
 module TokenAuthenticatableStrategies
   class Encrypted < Base
+    def initialize(*)
+      super
+
+      if migrating? && fallback?
+        raise ArgumentError, '`fallback` and `migration` options are not compatible!'
+      end
+    end
+
     def find_token_authenticatable(token, unscoped = false)
       return unless token
 
+      unless migrating?
         encrypted_value = Gitlab::CryptoHelper.aes256_gcm_encrypt(token)
         token_authenticatable = relation(unscoped)
           .find_by(encrypted_field => encrypted_value)
+      end
 
-      if fallback?
+      if migrating? || fallback?
         token_authenticatable ||= fallback_strategy
           .find_token_authenticatable(token)
       end
@@ -39,6 +49,8 @@ module TokenAuthenticatableStrategies
     end
 
     def get_token(instance)
+      return fallback_strategy.get_token(instance) if migrating?
+
       encrypted_token = instance.read_attribute(encrypted_field)
       token = Gitlab::CryptoHelper.aes256_gcm_decrypt(encrypted_token)
 
@@ -49,6 +61,7 @@ module TokenAuthenticatableStrategies
       raise ArgumentError unless token.present?
 
       instance[encrypted_field] = Gitlab::CryptoHelper.aes256_gcm_encrypt(token)
+      instance[token_field] = token if migrating?
       instance[token_field] = nil if fallback?
       token
     end

spec/models/concerns/token_authenticatable_strategies/encrypted_spec.rb

@@ -3,7 +3,6 @@ require 'spec_helper'
 describe TokenAuthenticatableStrategies::Encrypted do
   let(:model) { double(:model) }
   let(:instance) { double(:instance) }
-  let(:options) { { fallback: true } }
 
   let(:encrypted) do
     Gitlab::CryptoHelper.aes256_gcm_encrypt('my-value')
@@ -13,7 +12,20 @@ describe TokenAuthenticatableStrategies::Encrypted do
     described_class.new(model, 'some_field', options)
   end
 
+  describe '.new' do
+    context 'when fallback and migration strategies are set' do
+      let(:options) { { fallback: true, migrating: true } }
+
+      it 'raises an error' do
+        expect { subject }.to raise_error ArgumentError, /not compatible/
+      end
+    end
+  end
+
   describe '#find_token_authenticatable' do
+    context 'when using fallback strategy' do
+      let(:options) { { fallback: true } }
+
       it 'finds the encrypted resource by cleartext' do
         allow(model).to receive(:find_by)
           .with('some_field_encrypted' => encrypted)
@@ -37,7 +49,33 @@ describe TokenAuthenticatableStrategies::Encrypted do
       end
     end
 
+    context 'when using migration strategy' do
+      let(:options) { { migrating: true } }
+
+      it 'finds the cleartext resource by cleartext' do
+        allow(model).to receive(:find_by)
+          .with('some_field' => 'my-value')
+          .and_return('cleartext resource')
+
+        expect(subject.find_token_authenticatable('my-value'))
+          .to eq 'cleartext resource'
+      end
+
+      it 'returns nil if resource cannot be found' do
+        allow(model).to receive(:find_by)
+          .with('some_field' => 'my-value')
+          .and_return(nil)
+
+        expect(subject.find_token_authenticatable('my-value'))
+          .to be_nil
+      end
+    end
+  end
+
   describe '#get_token' do
+    context 'when using fallback strategy' do
+      let(:options) { { fallback: true } }
+
       it 'returns decrypted token when an encrypted token is present' do
         allow(instance).to receive(:read_attribute)
           .with('some_field_encrypted')
@@ -59,7 +97,39 @@ describe TokenAuthenticatableStrategies::Encrypted do
       end
     end
 
+    context 'when using migration strategy' do
+      let(:options) { { migrating: true } }
+
+      it 'returns cleartext token when an encrypted token is present' do
+        allow(instance).to receive(:read_attribute)
+          .with('some_field_encrypted')
+          .and_return(encrypted)
+
+        allow(instance).to receive(:read_attribute)
+          .with('some_field')
+          .and_return('my-cleartext-value')
+
+        expect(subject.get_token(instance)).to eq 'my-cleartext-value'
+      end
+
+      it 'returns the cleartext token when encrypted token is not present' do
+        allow(instance).to receive(:read_attribute)
+          .with('some_field_encrypted')
+          .and_return(nil)
+
+        allow(instance).to receive(:read_attribute)
+          .with('some_field')
+          .and_return('cleartext value')
+
+        expect(subject.get_token(instance)).to eq 'cleartext value'
+      end
+    end
+  end
+
   describe '#set_token' do
+    context 'when using fallback strategy' do
+      let(:options) { { fallback: true } }
+
       it 'writes encrypted token and removes plaintext token and returns it' do
         expect(instance).to receive(:[]=)
           .with('some_field_encrypted', encrypted)
@@ -69,4 +139,18 @@ describe TokenAuthenticatableStrategies::Encrypted do
         expect(subject.set_token(instance, 'my-value')).to eq 'my-value'
       end
     end
+
+    context 'when using migration strategy' do
+      let(:options) { { migrating: true } }
+
+      it 'writes encrypted token and writes plaintext token' do
+        expect(instance).to receive(:[]=)
+          .with('some_field_encrypted', encrypted)
+        expect(instance).to receive(:[]=)
+          .with('some_field', 'my-value')
+
+        expect(subject.set_token(instance, 'my-value')).to eq 'my-value'
+      end
+    end
+  end
 end