Add KAMAL.app_hosts

KAMAL.hosts includes accessory and apps hosts. Add KAMAL.app_hosts which
does not include accessory only hosts and use it for app specific
commands.

Fixes:
- https://github.com/basecamp/kamal/issues/1059
- https://github.com/basecamp/kamal/issues/1148

lib/kamal/cli/app.rb

@@ -7,7 +7,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
         say "Start container with version #{version} (or reboot if already running)...", :magenta
 
         # Assets are prepared in a separate step to ensure they are on all hosts before booting
-        on(KAMAL.hosts) do
+        on(KAMAL.app_hosts) do
           Kamal::Cli::App::ErrorPages.new(host, self).run
 
           KAMAL.roles_on(host).each do |role|
@@ -33,7 +33,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
         end
 
         # Tag once the app booted on all hosts
-        on(KAMAL.hosts) do |host|
+        on(KAMAL.app_hosts) do |host|
           execute *KAMAL.auditor.record("Tagging #{KAMAL.config.absolute_image} as the latest image"), verbosity: :debug
           execute *KAMAL.app.tag_latest_image
         end
@@ -44,7 +44,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
   desc "start", "Start existing app container on servers"
   def start
     with_lock do
-      on(KAMAL.hosts) do |host|
+      on(KAMAL.app_hosts) do |host|
         roles = KAMAL.roles_on(host)
 
         roles.each do |role|
@@ -67,7 +67,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
   desc "stop", "Stop app container on servers"
   def stop
     with_lock do
-      on(KAMAL.hosts) do |host|
+      on(KAMAL.app_hosts) do |host|
         roles = KAMAL.roles_on(host)
 
         roles.each do |role|
@@ -91,7 +91,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
   # FIXME: Drop in favor of just containers?
   desc "details", "Show details about app containers"
   def details
-    on(KAMAL.hosts) do |host|
+    on(KAMAL.app_hosts) do |host|
       roles = KAMAL.roles_on(host)
 
       roles.each do |role|
@@ -135,7 +135,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
       using_version(options[:version] || current_running_version) do |version|
         say "Launching command with version #{version} from existing container...", :magenta
 
-        on(KAMAL.hosts) do |host|
+        on(KAMAL.app_hosts) do |host|
           roles = KAMAL.roles_on(host)
 
           roles.each do |role|
@@ -149,7 +149,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
       say "Get most recent version available as an image...", :magenta unless options[:version]
       using_version(version_or_latest) do |version|
         say "Launching command with version #{version} from new container...", :magenta
-        on(KAMAL.hosts) do |host|
+        on(KAMAL.app_hosts) do |host|
           roles = KAMAL.roles_on(host)
 
           roles.each do |role|
@@ -163,7 +163,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
 
   desc "containers", "Show app containers on servers"
   def containers
-    on(KAMAL.hosts) { |host| puts_by_host host, capture_with_info(*KAMAL.app.list_containers) }
+    on(KAMAL.app_hosts) { |host| puts_by_host host, capture_with_info(*KAMAL.app.list_containers) }
   end
 
   desc "stale_containers", "Detect app stale containers"
@@ -172,7 +172,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
     stop = options[:stop]
 
     with_lock_if_stopping do
-      on(KAMAL.hosts) do |host|
+      on(KAMAL.app_hosts) do |host|
         roles = KAMAL.roles_on(host)
 
         roles.each do |role|
@@ -195,7 +195,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
 
   desc "images", "Show app images on servers"
   def images
-    on(KAMAL.hosts) { |host| puts_by_host host, capture_with_info(*KAMAL.app.list_images) }
+    on(KAMAL.app_hosts) { |host| puts_by_host host, capture_with_info(*KAMAL.app.list_images) }
   end
 
   desc "logs", "Show log lines from app on servers (use --help to show options)"
@@ -231,7 +231,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
     else
       lines = options[:lines].presence || ((since || grep) ? nil : 100) # Default to 100 lines if since or grep isn't set
 
-      on(KAMAL.hosts) do |host|
+      on(KAMAL.app_hosts) do |host|
         roles = KAMAL.roles_on(host)
 
         roles.each do |role|
@@ -288,7 +288,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
   desc "remove_container [VERSION]", "Remove app container with given version from servers", hide: true
   def remove_container(version)
     with_lock do
-      on(KAMAL.hosts) do |host|
+      on(KAMAL.app_hosts) do |host|
         roles = KAMAL.roles_on(host)
 
         roles.each do |role|
@@ -302,7 +302,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
   desc "remove_containers", "Remove all app containers from servers", hide: true
   def remove_containers
     with_lock do
-      on(KAMAL.hosts) do |host|
+      on(KAMAL.app_hosts) do |host|
         roles = KAMAL.roles_on(host)
 
         roles.each do |role|
@@ -316,7 +316,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
   desc "remove_images", "Remove all app images from servers", hide: true
   def remove_images
     with_lock do
-      on(KAMAL.hosts) do
+      on(KAMAL.app_hosts) do
         execute *KAMAL.auditor.record("Removed all app images"), verbosity: :debug
         execute *KAMAL.app.remove_images
       end
@@ -326,7 +326,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
   desc "remove_app_directories", "Remove the app directories from servers", hide: true
   def remove_app_directories
     with_lock do
-      on(KAMAL.hosts) do |host|
+      on(KAMAL.app_hosts) do |host|
         roles = KAMAL.roles_on(host)
 
         roles.each do |role|
@@ -342,7 +342,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
 
   desc "version", "Show app version currently running on servers"
   def version
-    on(KAMAL.hosts) do |host|
+    on(KAMAL.app_hosts) do |host|
       role = KAMAL.roles_on(host).first
       puts_by_host host, capture_with_info(*KAMAL.app(role: role, host: host).current_running_version).strip
     end
@@ -385,6 +385,6 @@ class Kamal::Cli::App < Kamal::Cli::Base
     end
 
     def host_boot_groups
-      KAMAL.config.boot.limit ? KAMAL.hosts.each_slice(KAMAL.config.boot.limit).to_a : [ KAMAL.hosts ]
+      KAMAL.config.boot.limit ? KAMAL.app_hosts.each_slice(KAMAL.config.boot.limit).to_a : [ KAMAL.app_hosts ]
     end
 end

lib/kamal/cli/build.rb

@@ -70,9 +70,9 @@ class Kamal::Cli::Build < Kamal::Cli::Base
       say "Pulling image on #{first_hosts.join(", ")} to seed the #{"mirror".pluralize(first_hosts.count)}...", :magenta
       pull_on_hosts(first_hosts)
       say "Pulling image on remaining hosts...", :magenta
-      pull_on_hosts(KAMAL.hosts - first_hosts)
+      pull_on_hosts(KAMAL.app_hosts - first_hosts)
     else
-      pull_on_hosts(KAMAL.hosts)
+      pull_on_hosts(KAMAL.app_hosts)
     end
   end
 
@@ -163,9 +163,9 @@ class Kamal::Cli::Build < Kamal::Cli::Base
     end
 
     def mirror_hosts
-      if KAMAL.hosts.many?
+      if KAMAL.app_hosts.many?
         mirror_hosts = Concurrent::Hash.new
-        on(KAMAL.hosts) do |host|
+        on(KAMAL.app_hosts) do |host|
           first_mirror = capture_with_info(*KAMAL.builder.first_mirror).strip.presence
           mirror_hosts[first_mirror] ||= host.to_s if first_mirror
         rescue SSHKit::Command::Failed => e
@@ -193,7 +193,7 @@ class Kamal::Cli::Build < Kamal::Cli::Base
     end
 
     def login_to_registry_remotely
-      on(KAMAL.hosts) do
+      on(KAMAL.app_hosts) do
         execute *KAMAL.registry.login
       end
     end

lib/kamal/cli/main.rb

@@ -194,10 +194,10 @@ class Kamal::Cli::Main < Kamal::Cli::Base
     confirming "This will replace Traefik with kamal-proxy and restart all accessories" do
       with_lock do
         if options[:rolling]
-          (KAMAL.hosts | KAMAL.accessory_hosts).each do |host|
+          KAMAL.hosts.each do |host|
             KAMAL.with_specific_hosts(host) do
               say "Upgrading #{host}...", :magenta
-              if KAMAL.hosts.include?(host)
+              if KAMAL.app_hosts.include?(host)
                 invoke "kamal:cli:proxy:upgrade", [], options.merge(confirmed: true, rolling: false)
                 reset_invocation(Kamal::Cli::Proxy)
               end
@@ -253,7 +253,7 @@ class Kamal::Cli::Main < Kamal::Cli::Base
   private
     def container_available?(version)
       begin
-        on(KAMAL.hosts) do
+        on(KAMAL.app_hosts) do
           KAMAL.roles_on(host).each do |role|
             container_id = capture_with_info(*KAMAL.app(role: role, host: host).container_id_for_version(version))
             raise "Container not found" unless container_id.present?

lib/kamal/cli/server.rb

@@ -3,7 +3,7 @@ class Kamal::Cli::Server < Kamal::Cli::Base
   option :interactive, type: :boolean, aliases: "-i", default: false, desc: "Run the command interactively (use for console/bash)"
   def exec(*cmd)
     cmd = Kamal::Utils.join_commands(cmd)
-    hosts = KAMAL.hosts | KAMAL.accessory_hosts
+    hosts = KAMAL.hosts
 
     case
     when options[:interactive]
@@ -27,7 +27,7 @@ class Kamal::Cli::Server < Kamal::Cli::Base
     with_lock do
       missing = []
 
-      on(KAMAL.hosts | KAMAL.accessory_hosts) do |host|
+      on(KAMAL.hosts) do |host|
         unless execute(*KAMAL.docker.installed?, raise_on_non_zero_exit: false)
           if execute(*KAMAL.docker.superuser?, raise_on_non_zero_exit: false)
             info "Missing Docker on #{host}. Installing…"

lib/kamal/commander.rb

@@ -5,7 +5,7 @@ require "active_support/core_ext/object/blank"
 class Kamal::Commander
   attr_accessor :verbosity, :holding_lock, :connected
   attr_reader :specific_roles, :specific_hosts
-  delegate :hosts, :roles, :primary_host, :primary_role, :roles_on, :proxy_hosts, :accessory_hosts, to: :specifics
+  delegate :hosts, :roles, :primary_host, :primary_role, :roles_on, :app_hosts, :proxy_hosts, :accessory_hosts, to: :specifics
 
   def initialize
     reset

lib/kamal/commander/specifics.rb

@@ -18,6 +18,10 @@ class Kamal::Commander::Specifics
     roles.select { |role| role.hosts.include?(host.to_s) }
   end
 
+  def app_hosts
+    config.app_hosts & specified_hosts
+  end
+
   def proxy_hosts
     config.proxy_hosts & specified_hosts
   end

lib/kamal/configuration.rb

@@ -125,6 +125,10 @@ class Kamal::Configuration
     (roles + accessories).flat_map(&:hosts).uniq
   end
 
+  def app_hosts
+    roles.flat_map(&:hosts).uniq
+  end
+
   def primary_host
     primary_role&.primary_host
   end

test/integration/docker/deployer/app/config/deploy.yml

@@ -41,3 +41,8 @@ accessories:
     cmd: sh -c 'echo "Starting busybox..."; trap exit term; while true; do sleep 1; done'
     roles:
       - web
+  busybox2:
+    service: custom-busybox
+    image: registry:4443/busybox:1.36.0
+    cmd: sh -c 'echo "Starting busybox..."; trap exit term; while true; do sleep 1; done'
+    host: vm3

test/integration/main_test.rb

@@ -60,7 +60,7 @@ class MainTest < IntegrationTest
     version = latest_app_version
 
     assert_equal [ "web" ], config[:roles]
-    assert_equal [ "vm1", "vm2" ], config[:hosts]
+    assert_equal [ "vm1", "vm2", "vm3" ], config[:hosts]
     assert_equal "vm1", config[:primary_host]
     assert_equal version, config[:version]
     assert_equal "registry:4443/app", config[:repository]
@@ -88,8 +88,6 @@ class MainTest < IntegrationTest
   end
 
   test "setup and remove" do
-    @app = "app_with_roles"
-
     kamal :proxy, :boot_config, "set",
       "--publish=false",
       "--docker-options=label=traefik.http.services.kamal_proxy.loadbalancer.server.scheme=http",
@@ -172,21 +170,25 @@ class MainTest < IntegrationTest
       assert_equal "200", Net::HTTP.get_response(URI.parse("http://#{app_host}:12345/versions/.hidden")).code
     end
 
-    def vm1_image_ids
+    def image_ids(vm:)
-      docker_compose("exec vm1 docker image ls -q", capture: true).strip.split("\n")
+      docker_compose("exec #{vm} docker image ls -q", capture: true).strip.split("\n")
     end
 
-    def vm1_container_ids
+    def container_ids(vm:)
-      docker_compose("exec vm1 docker ps -a -q", capture: true).strip.split("\n")
+      docker_compose("exec #{vm} docker ps -a -q", capture: true).strip.split("\n")
     end
 
     def assert_no_images_or_containers
-      assert vm1_image_ids.empty?
+      [ :vm1, :vm2, :vm3 ].each do |vm|
-      assert vm1_container_ids.empty?
+        assert image_ids(vm: vm).empty?
+        assert container_ids(vm: vm).empty?
+      end
     end
 
     def assert_images_and_containers
-      assert vm1_image_ids.any?
+      [ :vm1, :vm2, :vm3 ].each do |vm|
-      assert vm1_container_ids.any?
+        assert image_ids(vm: vm).any?
+        assert container_ids(vm: vm).any?
+      end
     end
 end