Merge pull request #810 from forward3d/host_filter

Add ability to filter tasks to specific servers (host filtering).

CHANGELOG.md

@@ -4,6 +4,7 @@ Reverse Chronological Order:
 
 ## master
 
+  * Add ability to filter tasks to specific servers (host filtering). (@andytinycat)
   * Add a command line option to control role filter (`--roles`) (@andytinycat)
   * Use an SCM object with a pluggable strategy
 

lib/capistrano/application.rb

@@ -16,7 +16,7 @@ module Capistrano
     end
 
     def sort_options(options)
-      options.push(version, dry_run, roles)
+      options.push(version, roles, dry_run, hostfilter)
       super
     end
 
@@ -74,6 +74,16 @@ module Capistrano
        }
       ]
     end
+    
+    def hostfilter
+      ['--hosts HOSTS', '-z',
+       "Filter command to only apply to these hosts (separate multiple hosts with a comma)",
+       lambda { |value|
+         Configuration.env.set(:filter, :hosts => value.split(","))
+       }
+      ]
+    end
+    
   end
 
 end

lib/capistrano/configuration/servers.rb

@@ -1,5 +1,6 @@
 require 'set'
 require_relative 'servers/role_filter'
+require_relative 'servers/host_filter'
 module Capistrano
   class Configuration
     class Servers
@@ -39,7 +40,7 @@ module Capistrano
 
       def fetch_roles(required, options)
         filter_roles = RoleFilter.for(required, available_roles)
-        select(servers_with_roles(filter_roles), options)
+        HostFilter.for(select(servers_with_roles(filter_roles), options))
       end
 
       def servers_with_roles(roles)

lib/capistrano/configuration/servers/host_filter.rb

@@ -0,0 +1,82 @@
+module Capistrano
+  class Configuration
+    class Servers
+      class HostFilter
+
+        def initialize(available)
+          @available = available
+        end
+
+        def self.for(available)
+          new(available).hosts
+        end
+
+        def hosts
+          if host_filter.any?  
+            @available.select { |server| host_filter.include? server.hostname }
+          else
+            @available
+          end
+        end
+
+        private
+
+        def filter
+          if host_filter.any?
+            host_filter
+          else
+            @available
+          end
+        end
+
+        def host_filter
+          env_filter | configuration_filter
+        end
+
+        def configuration_filter
+          ConfigurationFilter.new.hosts
+        end
+
+        def env_filter
+          EnvFilter.new.hosts
+        end
+
+        class ConfigurationFilter
+
+          def hosts
+            if filter
+              Array(filter.fetch(:hosts, []))
+            else
+              []
+            end
+          end
+
+          def config
+            Configuration.env
+          end
+
+          def filter
+            config.fetch(:filter) || config.fetch(:select)
+          end
+        end
+
+
+        class EnvFilter
+
+          def hosts
+            if filter
+              filter.split(',')
+            else
+              []
+            end
+          end
+
+          def filter
+            ENV['HOSTS']
+          end
+        end
+
+      end
+    end
+  end
+end

spec/lib/capistrano/configuration/servers/host_filter_spec.rb

@@ -0,0 +1,86 @@
+require 'spec_helper'
+
+module Capistrano
+  class Configuration
+    class Servers
+
+      describe HostFilter do
+        let(:host_filter) { HostFilter.new(available) }
+        let(:available) { [ Server.new('server1'), Server.new('server2'), Server.new('server3') ] }
+
+        describe '#new' do
+          it 'takes one array of hostnames' do
+            expect(host_filter)
+          end
+        end
+
+        describe '.for' do
+
+          subject { HostFilter.for(available) }
+
+          context 'without env vars' do
+            
+            it 'returns all available hosts' do
+              expect(subject).to eq available
+            end
+
+          end
+
+          context 'with ENV vars' do
+            before do
+              ENV.stubs(:[]).with('HOSTS').returns('server1,server2')
+            end
+
+            it 'returns all required hosts defined in HOSTS' do
+              expect(subject).to eq [Server.new('server1'), Server.new('server2')]
+            end
+          end
+
+          context 'with configuration filters' do
+            before do
+              Configuration.env.set(:filter, hosts: %w{server1 server2})
+            end
+
+            it 'returns all required hosts defined in the filter' do
+              expect(subject).to eq [Server.new('server1'), Server.new('server2')]
+            end
+
+            after do
+              Configuration.env.delete(:filter)
+            end
+          end
+
+          context 'with a single configuration filter' do
+            before do
+              Configuration.env.set(:filter, hosts: 'server3')
+            end
+
+            it 'returns all required hosts defined in the filter' do
+              expect(subject).to eq [Server.new('server3')]
+            end
+
+            after do
+              Configuration.env.delete(:filter)
+            end
+          end
+
+          context 'with configuration filters and ENV vars' do
+            before do
+              Configuration.env.set(:filter, hosts: 'server1')
+              ENV.stubs(:[]).with('HOSTS').returns('server3')
+            end
+
+            it 'returns all required hosts defined in the filter' do
+              expect(subject).to eq [Server.new('server1'), Server.new('server3')]
+            end
+
+            after do
+              Configuration.env.delete(:filter)
+            end
+          end
+        end
+      end
+
+    end
+  end
+end

spec/lib/capistrano/configuration/servers_spec.rb

@@ -179,6 +179,7 @@ module Capistrano
 
         before do
           ENV.stubs(:[]).with('ROLES').returns('web,db')
+          ENV.stubs(:[]).with('HOSTS').returns(nil)
           servers.add_host('1', roles: :app, active: true)
           servers.add_host('2', roles: :app)
           servers.add_host('3', roles: :web)