Allow arrays to be passed through env variables (#354)

* Allow arrays to be passed through env variables

* Fix "Config::Sources::EnvSource configuration options default configuration arrays when loading nested configurations retains hashes for mixed types" spec

* add `Config.env_parse_arrays`

---------

Co-authored-by: dominh <>
Co-authored-by: Dominik Mlynek <[email protected]>
Co-authored-by: Chris LaRose <[email protected]>

lib/config.rb

@@ -18,6 +18,7 @@ module Config
     env_separator: '.',
     env_converter: :downcase,
     env_parse_values: true,
+    env_parse_arrays: false,
     fail_on_missing: false,
     file_name: 'settings',
     dir_name: 'settings',

lib/config/sources/env_source.rb

@@ -6,17 +6,20 @@ class EnvSource
       attr_reader :separator
       attr_reader :converter
       attr_reader :parse_values
+      attr_reader :parse_arrays
 
       def initialize(env,
                      prefix: Config.env_prefix || Config.const_name,
                      separator: Config.env_separator,
                      converter: Config.env_converter,
-                     parse_values: Config.env_parse_values)
+                     parse_values: Config.env_parse_values,
+                     parse_arrays: Config.env_parse_arrays)
         @env = env
         @prefix = prefix.to_s.split(separator)
         @separator = separator
         @converter = converter
         @parse_values = parse_values
+        @parse_arrays = parse_arrays
       end
 
       def load
@@ -52,10 +55,28 @@ def load
           leaf[keys.last] = parse_values ? __value(value) : value
         end
 
-        hash
+        parse_arrays ? convert_hashes_to_arrays(hash) : hash
       end
 
       private
+      def convert_hashes_to_arrays(hash)
+        hash.each_with_object({}) do |(key, value), new_hash|
+          if value.is_a?(Hash)
+            value = convert_hashes_to_arrays(value)
+            if consecutive_numeric_keys?(value.keys)
+              new_hash[key] = value.keys.sort_by(&:to_i).map { |k| value[k] }
+            else
+              new_hash[key] = value
+            end
+          else
+            new_hash[key] = value
+          end
+        end
+      end
+
+      def consecutive_numeric_keys?(keys)
+        keys.map(&:to_i).sort == (0...keys.size).to_a && keys.all? { |k| k == k.to_i.to_s }
+      end
 
       # Try to convert string to a correct type
       def __value(v)

spec/config_env_spec.rb

@@ -22,6 +22,7 @@
       Config.env_separator        = '.'
       Config.env_converter        = :downcase
       Config.env_parse_values     = true
+      Config.env_parse_arrays     = true
     end
 
     it 'should add new setting from ENV variable' do
@@ -96,6 +97,36 @@
       end
     end
 
+    context 'and parsing ENV variables arrays' do
+      context 'is enabled' do
+        before :each do
+          Config.env_parse_arrays = true
+        end
+
+        it 'should recognize ENV variables with subsequent numeric suffixes starting from 0 as array' do
+          ENV['Settings.SomeConfig.0'] = 'first'
+          ENV['Settings.SomeConfig.1'] = 'second'
+
+          expect(config.someconfig).to eq(['first', 'second'])
+        end
+      end
+
+      context 'is disabled' do
+        before :each do
+          Config.env_parse_arrays = false
+        end
+
+        it 'should not recognize ENV variables with subsequent numeric suffixes starting from 0 as array' do
+          ENV['Settings.SomeConfig.0'] = 'first'
+          ENV['Settings.SomeConfig.1'] = 'second'
+
+          expect(config.someconfig).to be_a Config::Options
+          expect(config.someconfig['0']).to eq('first')
+          expect(config.someconfig['1']).to eq('second')
+        end
+      end
+    end
+
     context 'and custom ENV variables prefix is defined' do
       before :each do
         Config.env_prefix = 'MyConfig'

spec/sources/env_source_spec.rb

@@ -43,6 +43,49 @@ module Config::Sources
           results = source.load
           expect(results['action_mailer']['enabled']).to eq('true')
         end
+
+        describe 'arrays' do
+          before(:each) do
+            Config.env_parse_arrays = true
+          end
+
+          let(:source) do
+            Config.env_converter = nil
+            EnvSource.new({
+                            'Settings.SomeConfig.0.0' => 'value1',
+                            'Settings.SomeConfig.0.1' => 'value2',
+                            'Settings.SomeConfig.1.1' => 'value3',
+                            'Settings.SomeConfig.1.2' => 'value4',
+                            'Settings.MixedConfig.1.0' => 'value5',
+                            'Settings.MixedConfig.1.1' => 'value6',
+                            'Settings.MixedConfig.1.custom' => 'value7'
+                          })
+          end
+
+          let(:results) { source.load }
+
+          context 'when loading nested configurations' do
+            it 'converts numeric-keyed hashes to arrays' do
+              expect(results['SomeConfig']).to be_an Array
+              expect(results['SomeConfig'][0]).to be_an Array
+              expect(results['SomeConfig'][0][0]).to eq('value1')
+              expect(results['SomeConfig'][0][1]).to eq('value2')
+            end
+
+            it 'retains hashes for non-sequential numeric keys' do
+              expect(results['SomeConfig'][1]).to be_a Hash
+              expect(results['SomeConfig'][1]['1']).to eq('value3')
+              expect(results['SomeConfig'][1]['2']).to eq('value4')
+            end
+
+            it 'retains hashes for mixed types' do
+              expect(results['MixedConfig']['1']).to be_a Hash
+              expect(results['MixedConfig']['1']['0']).to eq('value5')
+              expect(results['MixedConfig']['1']['1']).to eq('value6')
+              expect(results['MixedConfig']['1']['custom']).to eq('value7')
+            end
+          end
+        end
       end
 
       context 'configuration overrides' do