Don't set a default minimum healthy percentage of 100% anymore,

so either the default of 90% will be used, or the percentage set
in the instance maintenance policy for the ASG.

Introduce the properties `min_healthy_percentage` and `max_healthy_percentage`
on the autoscale definitions for tuning these settings.

The property `healthy_percentage` is still supported but
will give a deprecation warning, and will be removed somewhere in the future.

Gem `aws-sdk-autoscaling` >= 1.100.0 is now required to support
setting the maximum healthy percentage.

.rubocop.yml

@@ -38,3 +38,6 @@ RSpec/IndexedLet:
 
 RSpec/MultipleExpectations:
   Max: 5
+
+Style/GuardClause:
+  Enabled: false

Gemfile.lock

@@ -2,7 +2,7 @@ PATH
   remote: .
   specs:
     capistrano-asg-rolling (0.4.1)
-      aws-sdk-autoscaling (~> 1, >= 1.67.0)
+      aws-sdk-autoscaling (~> 1, >= 1.100.0)
       aws-sdk-ec2 (~> 1)
       capistrano (~> 3)
       concurrent-ruby (~> 1)

capistrano-asg-rolling.gemspec

@@ -33,7 +33,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'rspec', '~> 3.0'
   spec.add_development_dependency 'webmock', '~> 3.11'
 
-  spec.add_dependency 'aws-sdk-autoscaling', '~> 1', '>= 1.67.0'
+  spec.add_dependency 'aws-sdk-autoscaling', '~> 1', '>= 1.100.0'
   spec.add_dependency 'aws-sdk-ec2', '~> 1'
   spec.add_dependency 'capistrano', '~> 3'
   spec.add_dependency 'concurrent-ruby', '~> 1'

lib/capistrano/asg/rolling/autoscale_group.rb

@@ -19,6 +19,12 @@ class AutoscaleGroup
         def initialize(name, properties = {})
           @name = name
           @properties = properties
+
+          if properties[:healthy_percentage]
+            properties[:min_healthy_percentage] = properties.delete(:healthy_percentage)
+
+            Kernel.warn('WARNING: the property `healthy_percentage` is deprecated and will be removed in a future release. Please update to `min_healthy_percentage`.')
+          end
         end
 
         def exists?
@@ -42,8 +48,12 @@ def instance_warmup_time
           aws_autoscaling_group.health_check_grace_period
         end
 
-        def healthy_percentage
-          properties.fetch(:healthy_percentage, 100)
+        def min_healthy_percentage
+          properties.fetch(:min_healthy_percentage, nil)
+        end
+
+        def max_healthy_percentage
+          properties.fetch(:max_healthy_percentage, nil)
         end
 
         def start_instance_refresh(launch_template)
@@ -58,9 +68,10 @@ def start_instance_refresh(launch_template)
             },
             preferences: {
               instance_warmup: instance_warmup_time,
-              min_healthy_percentage: healthy_percentage,
-              skip_matching: true
-            }
+              skip_matching: true,
+              min_healthy_percentage: min_healthy_percentage,
+              max_healthy_percentage: max_healthy_percentage
+            }.compact
           ).instance_refresh_id
         rescue Aws::AutoScaling::Errors::InstanceRefreshInProgress => e
           raise Capistrano::ASG::Rolling::InstanceRefreshFailed, e

spec/capistrano/asg/rolling/autoscale_group_spec.rb

@@ -63,18 +63,34 @@
     end
   end
 
-  describe '#healthy_percentage' do
+  describe '#min_healthy_percentage' do
     context 'when no value is set' do
-      it 'returns the default healthy percentage (100)' do
-        expect(group.healthy_percentage).to eq(100)
+      it 'returns nil' do
+        expect(group.min_healthy_percentage).to be_nil
       end
     end
 
     context 'when a value is set' do
-      subject(:group) { described_class.new('test-asg', healthy_percentage: 50) }
+      subject(:group) { described_class.new('test-asg', min_healthy_percentage: 50) }
 
       it 'returns the value set in the configuration (50)' do
-        expect(group.healthy_percentage).to eq(50)
+        expect(group.min_healthy_percentage).to eq(50)
+      end
+    end
+  end
+
+  describe '#max_healthy_percentage' do
+    context 'when no value is set' do
+      it 'returns nil' do
+        expect(group.max_healthy_percentage).to be_nil
+      end
+    end
+
+    context 'when a value is set' do
+      subject(:group) { described_class.new('test-asg', max_healthy_percentage: 110) }
+
+      it 'returns the value set in the configuration (110)' do
+        expect(group.max_healthy_percentage).to eq(110)
       end
     end
   end
@@ -108,6 +124,16 @@
         expect { group.start_instance_refresh(template) }.to raise_error(Capistrano::ASG::Rolling::InstanceRefreshFailed, 'An Instance Refresh is already in progress and blocks the execution of this Instance Refresh.')
       end
     end
+
+    context 'when min and max healthy percentage is set' do
+      subject(:group) { described_class.new('test-asg', min_healthy_percentage: 50, max_healthy_percentage: 110) }
+
+      it 'calls the API to start instance refresh with the given healthy percentages' do
+        group.start_instance_refresh(template)
+        expect(WebMock).to have_requested(:post, /amazonaws.com/)
+          .with(body: /Action=StartInstanceRefresh&AutoScalingGroupName=test-asg&DesiredConfiguration.LaunchTemplate.LaunchTemplateId=lt-1234567890&DesiredConfiguration.LaunchTemplate.Version=1&Preferences.InstanceWarmup=300&Preferences.MaxHealthyPercentage=110&Preferences.MinHealthyPercentage=50&Preferences.SkipMatching=true&Strategy=Rolling/).once
+      end
+    end
   end
 
   describe '#instances' do