Rename roles

Allow roles to be renamed without having to manually stop the old
containers.

If you have config like:

```
servers:
  jobs:
    hosts:
      - vm3
```

And you want to rename `jobs` to `workers`, you can do:

```
servers:
  workers:
    previously:
      - jobs
    hosts:
      - vm3
```

And the deployment will take care of stopping the old "jobs" containers.

Once deployed you can remove the `previously` key.

lib/kamal/cli/app/boot.rb

@@ -11,12 +11,12 @@ class Kamal::Cli::App::Boot
   end
 
   def run
-    old_version = old_version_renamed_if_clashing
+    old_version, old_app = old_version_renamed_if_clashing
 
     start_new_version
 
     if old_version
-      stop_old_version(old_version)
+      stop_old_version(old_version, old_app)
     end
   end
 
@@ -41,7 +41,13 @@ class Kamal::Cli::App::Boot
         execute *app.rename_container(version: version, new_version: renamed_version)
       end
 
-      capture_with_info(*app.current_running_version, raise_on_non_zero_exit: false).strip.presence
+      [ role, *role.previous_roles ].each do |old_role|
+        old_app = KAMAL.app(role: old_role)
+        old_version = capture_with_info(*old_app.current_running_version, raise_on_non_zero_exit: false).strip.presence
+        return [ old_version, old_app ] if old_version
+      end
+
+      nil
     end
 
     def start_new_version
@@ -51,7 +57,7 @@ class Kamal::Cli::App::Boot
       Kamal::Cli::Healthcheck::Poller.wait_for_healthy(pause_after_ready: true) { capture_with_info(*app.status(version: version)) }
     end
 
-    def stop_old_version(version)
+    def stop_old_version(version, app)
       if uses_cord?
         cord = capture_with_info(*app.cord(version: version), raise_on_non_zero_exit: false).strip
         if cord.present?

lib/kamal/commands/app.rb

@@ -3,7 +3,7 @@ class Kamal::Commands::App < Kamal::Commands::Base
 
   ACTIVE_DOCKER_STATUSES = [ :running, :restarting ]
 
-  attr_reader :role, :role
+  attr_reader :role
 
   def initialize(config, role: nil)
     super(config)

lib/kamal/configuration.rb

@@ -71,7 +71,9 @@ class Kamal::Configuration
 
 
   def roles
-    @roles ||= role_names.collect { |role_name| Role.new(role_name, config: self) }
+    @roles ||= role_names.collect do |role_name|
+      Role.new(role_name, config: self, specializations: role_specializations(role_name), primary: role_name == primary_role_name)
+    end
   end
 
   def role(name)
@@ -325,6 +327,14 @@ class Kamal::Configuration
       raw_config.servers.is_a?(Array) ? [ "web" ] : raw_config.servers.keys.sort
     end
 
+    def role_specializations(name)
+      if servers.is_a?(Array) || servers[name].is_a?(Array)
+        {}
+      else
+        servers[name].except("hosts")
+      end
+    end
+
     def git_version
       @git_version ||=
         if Kamal::Git.used?

lib/kamal/configuration/role.rb

@@ -2,11 +2,11 @@ class Kamal::Configuration::Role
   CORD_FILE = "cord"
   delegate :argumentize, :optionize, to: Kamal::Utils
 
-  attr_accessor :name
+  attr_reader :name
   alias to_s name
 
-  def initialize(name, config:)
-    @name, @config = name.inquiry, config
+  def initialize(name, config:, specializations:, primary:)
+    @name, @config, @specializations, @primary = name.inquiry, config, specializations, primary
   end
 
   def primary_host
@@ -98,7 +98,7 @@ class Kamal::Configuration::Role
   end
 
   def primary?
-    self == @config.primary_role
+    @primary
   end
 
 
@@ -163,8 +163,14 @@ class Kamal::Configuration::Role
     File.join config.run_directory, "assets", "volumes", container_name(version)
   end
 
+  def previous_roles
+    previous_role_names.map do |role_name|
+      Kamal::Configuration::Role.new(role_name, config: config, specializations: specializations, primary: primary?)
+    end
+  end
+
   private
-    attr_accessor :config
+    attr_reader :config, :specializations
 
     def extract_hosts_from_config
       if config.servers.is_a?(Array)
@@ -207,14 +213,6 @@ class Kamal::Configuration::Role
       end
     end
 
-    def specializations
-      if config.servers.is_a?(Array) || config.servers[name].is_a?(Array)
-        {}
-      else
-        config.servers[name].except("hosts")
-      end
-    end
-
     def specialized_env
       Kamal::Configuration::Env.from_config config: specializations.fetch("env", {})
     end
@@ -237,4 +235,8 @@ class Kamal::Configuration::Role
         options
       end
     end
+
+    def previous_role_names
+      specializations.fetch("previously", [])
+    end
 end

test/configuration/role_test.rb

@@ -53,7 +53,8 @@ class ConfigurationRoleTest < ActiveSupport::TestCase
   test "custom labels via role specialization" do
     @deploy_with_roles[:labels] = { "my.custom.label" => "50" }
     @deploy_with_roles[:servers]["workers"]["labels"] = { "my.custom.label" => "70" }
-    assert_equal "70", @config_with_roles.role(:workers).labels["my.custom.label"]
+    config_with_roles = Kamal::Configuration.new(@deploy_with_roles)
+    assert_equal "70", config_with_roles.role(:workers).labels["my.custom.label"]
   end
 
   test "overwriting default traefik label" do
@@ -109,6 +110,8 @@ class ConfigurationRoleTest < ActiveSupport::TestCase
       ]
     }
 
+    config_with_roles = Kamal::Configuration.new(@deploy_with_roles)
+
     ENV["REDIS_PASSWORD"] = "secret456"
     ENV["DB_PASSWORD"] = "secret&\"123"
 
@@ -117,8 +120,8 @@ class ConfigurationRoleTest < ActiveSupport::TestCase
       DB_PASSWORD=secret&\"123
     ENV
 
-    assert_equal expected_secrets_file, @config_with_roles.role(:workers).env.secrets_io.string
-    assert_equal [ "--env-file", ".kamal/env/roles/app-workers.env", "--env", "REDIS_URL=\"redis://a/b\"", "--env", "WEB_CONCURRENCY=\"4\"" ], @config_with_roles.role(:workers).env_args
+    assert_equal expected_secrets_file, config_with_roles.role(:workers).env.secrets_io.string
+    assert_equal [ "--env-file", ".kamal/env/roles/app-workers.env", "--env", "REDIS_URL=\"redis://a/b\"", "--env", "WEB_CONCURRENCY=\"4\"" ], config_with_roles.role(:workers).env_args
   ensure
     ENV["REDIS_PASSWORD"] = nil
     ENV["DB_PASSWORD"] = nil
@@ -135,14 +138,16 @@ class ConfigurationRoleTest < ActiveSupport::TestCase
       ]
     }
 
+    config_with_roles = Kamal::Configuration.new(@deploy_with_roles)
+
     ENV["DB_PASSWORD"] = "secret123"
 
     expected_secrets_file = <<~ENV
       DB_PASSWORD=secret123
     ENV
 
-    assert_equal expected_secrets_file, @config_with_roles.role(:workers).env.secrets_io.string
-    assert_equal [ "--env-file", ".kamal/env/roles/app-workers.env", "--env", "REDIS_URL=\"redis://a/b\"", "--env", "WEB_CONCURRENCY=\"4\"" ], @config_with_roles.role(:workers).env_args
+    assert_equal expected_secrets_file, config_with_roles.role(:workers).env.secrets_io.string
+    assert_equal [ "--env-file", ".kamal/env/roles/app-workers.env", "--env", "REDIS_URL=\"redis://a/b\"", "--env", "WEB_CONCURRENCY=\"4\"" ], config_with_roles.role(:workers).env_args
   ensure
     ENV["DB_PASSWORD"] = nil
   end
@@ -185,14 +190,16 @@ class ConfigurationRoleTest < ActiveSupport::TestCase
       }
     }
 
+    config_with_roles = Kamal::Configuration.new(@deploy_with_roles)
+
     ENV["REDIS_PASSWORD"] = "secret456"
 
     expected_secrets_file = <<~ENV
       REDIS_PASSWORD=secret456
     ENV
 
-    assert_equal expected_secrets_file, @config_with_roles.role(:workers).env.secrets_io.string
-    assert_equal [ "--env-file", ".kamal/env/roles/app-workers.env", "--env", "REDIS_URL=\"redis://c/d\"" ], @config_with_roles.role(:workers).env_args
+    assert_equal expected_secrets_file, config_with_roles.role(:workers).env.secrets_io.string
+    assert_equal [ "--env-file", ".kamal/env/roles/app-workers.env", "--env", "REDIS_URL=\"redis://c/d\"" ], config_with_roles.role(:workers).env_args
   ensure
     ENV["REDIS_PASSWORD"] = nil
   end

test/integration/docker/deployer/app_with_roles/config/deploy_renamed_roles.yml

@@ -0,0 +1,42 @@
+service: app
+image: app
+primary_role: app
+servers:
+  app:
+    previously:
+      - web
+    hosts:
+      - vm1
+      - vm2
+  jobs:
+    previously:
+      - workers
+    hosts:
+      - vm3
+    cmd: sleep infinity
+
+asset_path: /usr/share/nginx/html/versions
+
+registry:
+  server: registry:4443
+  username: root
+  password: root
+builder:
+  multiarch: false
+  args:
+    COMMIT_SHA: <%= `git rev-parse HEAD` %>
+healthcheck:
+  cmd: wget -qO- http://localhost > /dev/null || exit 1
+traefik:
+  args:
+    accesslog: true
+    accesslog.format: json
+  image: registry:4443/traefik:v2.10
+accessories:
+  busybox:
+    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'
+    roles:
+      - app
+stop_wait_time: 1

test/integration/docker/deployer/rename_roles.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+cd $1 && cp -f config/deploy_renamed_roles.yml config/deploy.yml && git commit -am 'Rename roles'

test/integration/integration_test.rb

@@ -131,4 +131,16 @@ class IntegrationTest < ActiveSupport::TestCase
         puts "Tried to get the response code again and got #{app_response.code}"
       end
     end
+
+    def assert_container_running(host:, name:)
+      assert container_running?(host: host, name: name)
+    end
+
+    def assert_container_not_running(host:, name:)
+      assert_not container_running?(host: host, name: name)
+    end
+
+    def container_running?(host:, name:)
+      docker_compose("exec #{host} docker ps --filter=name=#{name} | tail -n+2", capture: true).strip.present?
+    end
 end

test/integration/main_test.rb

@@ -92,6 +92,33 @@ class MainTest < IntegrationTest
     assert_no_images_or_containers
   end
 
+  test "rename roles" do
+    @app = "app_with_roles"
+
+    kamal :envify
+    kamal :deploy
+
+    first_version = latest_app_version
+
+    assert_container_running host: :vm1, name: "app-web-#{first_version}"
+    assert_container_running host: :vm2, name: "app-web-#{first_version}"
+    assert_container_running host: :vm3, name: "app-workers-#{first_version}"
+
+    rename_roles
+
+    kamal :envify
+    kamal :deploy
+
+    second_version = latest_app_version
+
+    assert_container_running host: :vm1, name: "app-app-#{second_version}"
+    assert_container_running host: :vm2, name: "app-app-#{second_version}"
+    assert_container_running host: :vm3, name: "app-jobs-#{second_version}"
+    assert_container_not_running host: :vm1, name: "app-web-#{first_version}"
+    assert_container_not_running host: :vm2, name: "app-web-#{first_version}"
+    assert_container_not_running host: :vm3, name: "app-workers-#{first_version}"
+  end
+
   private
     def assert_local_env_file(contents)
       assert_equal contents, deployer_exec("cat .env", capture: true)
@@ -139,7 +166,7 @@ class MainTest < IntegrationTest
       assert vm1_container_ids.any?
     end
 
-    def assert_container_running(host:, name:)
-      assert docker_compose("exec #{host} docker ps --filter=name=#{name} -q", capture: true).strip.present?
+    def rename_roles
+      deployer_exec "./rename_roles.sh #{@app}", workdir: "/"
     end
 end