Add the ability to hint the rolling_deploy with a named ELB

capify-ec2.gemspec

@@ -19,7 +19,9 @@ Gem::Specification.new do |s|
   s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
   s.require_paths = ["lib"]
-  s.add_dependency('fog', '>= 1.23.0')
+  s.add_dependency('fog', '=1.23.0')
+  s.add_dependency('aws-sdk', '~> 3')
   s.add_dependency('colored', '=1.2')
   s.add_dependency('capistrano', '~> 2.14')
+  s.add_dependency('net-ssh', '=3.0.2')
 end

lib/capify-ec2.rb

@@ -266,7 +266,6 @@ def get_load_balancer_by_name(load_balancer_name)
       lbs[load_balancer.id] = load_balancer
     end
     lbs[load_balancer_name]
-
   end
 
   def deregister_instance_from_elb(instance_name)
@@ -306,6 +305,34 @@ def register_instance_in_elb(instance_name, load_balancer_name = '')
     end
   end
 
+  def deregister_instance_from_named_elbs_by_dns(server_dns, load_balancer_names)
+    instance = get_instance_by_dns(server_dns)
+
+    lbs = []
+    threads = []
+
+    for load_balancer_name in load_balancer_names do
+      threads << Thread.new(load_balancer_name) do |lb|
+        load_balancer = get_load_balancer_by_name(lb)
+
+        if load_balancer
+          puts "[Capify-EC2] Removing instance from named ELB '#{load_balancer.id}'..."
+
+          result = elb.deregister_instances_from_load_balancer(instance.id, load_balancer.id)
+          raise "Unable to remove instance from ELB '#{load_balancer.id}'..." unless result.status == 200
+
+          lbs << load_balancer
+        end
+      end
+    end
+
+    for t in threads do
+      t.join
+    end
+
+    lbs
+  end
+
   def deregister_instance_from_elb_by_dns(server_dns)
     instance = get_instance_by_dns(server_dns)
     load_balancer = get_load_balancer_by_instance(instance.id)
@@ -316,7 +343,11 @@ def deregister_instance_from_elb_by_dns(server_dns)
       result = elb.deregister_instances_from_load_balancer(instance.id, load_balancer.id)
       raise "Unable to remove instance from ELB '#{load_balancer.id}'..." unless result.status == 200
 
-      return load_balancer
+      #TODO: The ability to remove an instance from multiple ELBs has been added, which returns an [] of elbs.
+      #I've taken a shortcut here to return an array for this (the single ELB case). However, the correct solution
+      #would be to extend the above method to remove an instance from multiple ELBs by DNS too.
+      #This may break things for some users however? Needs to be checked.
+      return [load_balancer]
     end
     false
   end

lib/capify-ec2/capistrano.rb

@@ -121,19 +121,28 @@ def capify_ec2
 
         roles.clear
 
-        load_balancer_to_reregister = nil # Set to nil again here, to ensure it always starts off nil for every iteration.
+        load_balancers_to_reregister = [] # Set to empty again here, to ensure it always starts off empty for every iteration.
         is_load_balanced = false
+        load_balancer_names = false
 
         server_roles.each do |a_role|
           role a_role, server_dns, all_options[a_role][server_dns]
           is_load_balanced = true if all_options[a_role][server_dns][:load_balanced]
+
+          if all_options[a_role][server_dns][:elb_names]
+            load_balancer_names = all_options[a_role][server_dns][:elb_names]
+          end
         end
 
         puts "[Capify-EC2]"
         puts "[Capify-EC2] (#{index+1} of #{all_servers.length}) Beginning deployment to #{instance_dns_with_name_tag(server_dns)} with #{server_roles.count > 1 ? 'roles' : 'role'} '#{server_roles.join(', ')}'...".bold
 
-        unless dry_run
-          load_balancer_to_reregister = capify_ec2.deregister_instance_from_elb_by_dns(server_dns) if is_load_balanced
+        if is_load_balanced && !dry_run
+          if load_balancer_names
+            load_balancers_to_reregister = capify_ec2.deregister_instance_from_named_elbs_by_dns(server_dns, load_balancer_names)
+          else
+            load_balancers_to_reregister = capify_ec2.deregister_instance_from_elb_by_dns(server_dns)
+          end
         end
 
         # Call the standard 'cap deploy' task with our redefined role containing a single server.
@@ -165,19 +174,28 @@ def capify_ec2
               end
             end
           end
-
         end
 
-        if load_balancer_to_reregister
-          reregistered = capify_ec2.reregister_instance_with_elb_by_dns(server_dns, load_balancer_to_reregister, 60)
-          if reregistered
-            puts "[Capify-EC2] Instance registration with ELB '#{load_balancer_to_reregister.id}' successful.".green.bold
-          else
-            puts "[Capify-EC2] Instance registration with ELB '#{load_balancer_to_reregister.id}' failed!".red.bold
-            raise CapifyEC2RollingDeployError.new("ELB registration timeout exceeded", server_dns)
+        threads = []
+
+        for load_balancer_to_reregister in load_balancers_to_reregister do
+          threads << Thread.new(load_balancer_to_reregister) do |lb|
+            puts "[Capify-EC2] Starting registration of ELB '#{lb.id}'"
+
+            reregistered = capify_ec2.reregister_instance_with_elb_by_dns(server_dns, lb, 60)
+            if reregistered
+              puts "[Capify-EC2] Instance registration with ELB '#{lb.id}' successful.".green.bold
+            else
+              puts "[Capify-EC2] Instance registration with ELB '#{lb.id}' failed!".red.bold
+              raise CapifyEC2RollingDeployError.new("ELB registration timeout exceeded", server_dns)
+            end  
           end
         end
 
+        for t in threads do
+          t.join
+        end
+
         puts "[Capify-EC2] Deployment successful to #{instance_dns_with_name_tag(server_dns)}.".green.bold
         successful_deploys << server_dns
 
@@ -327,4 +345,4 @@ def pluralise(n, singular, plural=nil)
         "#{singular}s"
     end
   end
-end
+end

readme.md

@@ -550,7 +550,20 @@ If an instance has been tagged with multiple roles, this behaviour will apply if
 
 If an instance is not associated with any ELBs, then the behaviour will be skipped silently, even if `:load_balanced` is set to 'true'.
 
+If an instance belongs to multiple ELBs (e.g. a single instance pointed to by separate ELBs), you can force which ELBs are chosen by using the :elb_names parameter like this:
 
+```ruby
+ec2_roles :name => "web",
+          :variables => {
+            :healthcheck => {
+                :path   => '/status',
+                :port   => 80,
+                :result => 'OK'
+              }
+            :load_balanced => true,
+            :elb_names => ["the_name_of_your_elb", "the_name_of_another_elb"]
+          }
+```
 
 #### Viewing All Instances