Custom proxy image registry, repo and version

Use the --registry, --repository and --image_version options of
`kamal proxy boot_config set` to change the kamal-proxy image used.

We'll still insist that the image version is at least as high as the
minimum.

lib/kamal/cli/proxy.rb

@@ -27,6 +27,9 @@ class Kamal::Cli::Proxy < Kamal::Cli::Base
   option :http_port, type: :numeric, default: Kamal::Configuration::PROXY_HTTP_PORT, desc: "HTTP port to publish on the host"
   option :https_port, type: :numeric, default: Kamal::Configuration::PROXY_HTTPS_PORT, desc: "HTTPS port to publish on the host"
   option :log_max_size, type: :string, default: Kamal::Configuration::PROXY_LOG_MAX_SIZE, desc: "Max size of proxy logs"
+  option :registry, type: :string, default: nil, desc: "Registry to use for the proxy image"
+  option :repository, type: :string, default: nil, desc: "Repository for the proxy image"
+  option :image_version, type: :string, default: nil, desc: "Version of the proxy to run"
   option :docker_options, type: :array, default: [], desc: "Docker options to pass to the proxy container", banner: "option=value option2=value2"
   def boot_config(subcommand)
     case subcommand
@@ -37,17 +40,43 @@ class Kamal::Cli::Proxy < Kamal::Cli::Base
         *options[:docker_options].map { |option| "--#{option}" }
       ]
 
+      default_boot_options = [
+        *(KAMAL.config.proxy_publish_args(Kamal::Configuration::PROXY_HTTP_PORT, Kamal::Configuration::PROXY_HTTPS_PORT, nil)),
+        *(KAMAL.config.proxy_logging_args(Kamal::Configuration::PROXY_LOG_MAX_SIZE)),
+      ]
+
+      image = [ options[:registry].presence, options[:repository] || KAMAL.config.proxy_repository_name, KAMAL.config.proxy_image_name ].compact.join("/")
+      image_version = options[:image_version]
+
       on(KAMAL.proxy_hosts) do |host|
         execute(*KAMAL.proxy.ensure_proxy_directory)
-        upload! StringIO.new(boot_options.join(" ")), KAMAL.config.proxy_options_file
+        if boot_options != default_boot_options
+          upload! StringIO.new(boot_options.join(" ")), KAMAL.config.proxy_options_file
+        else
+          execute *KAMAL.proxy.reset_boot_options, raise_on_non_zero_exit: false
+        end
+
+        if image != KAMAL.config.proxy_image_default
+          upload! StringIO.new(image), KAMAL.config.proxy_image_file
+        else
+          execute *KAMAL.proxy.reset_image, raise_on_non_zero_exit: false
+        end
+
+        if image_version
+          upload! StringIO.new(image_version), KAMAL.config.proxy_image_version_file
+        else
+          execute *KAMAL.proxy.reset_image_version, raise_on_non_zero_exit: false
+        end
       end
     when "get"
       on(KAMAL.proxy_hosts) do |host|
-        puts "Host #{host}: #{capture_with_info(*KAMAL.proxy.get_boot_options)}"
+        puts "Host #{host}: #{capture_with_info(*KAMAL.proxy.boot_config)}"
       end
     when "reset"
       on(KAMAL.proxy_hosts) do |host|
-        execute *KAMAL.proxy.reset_boot_options
+        execute *KAMAL.proxy.reset_boot_options, raise_on_non_zero_exit: false
+        execute *KAMAL.proxy.reset_image, raise_on_non_zero_exit: false
+        execute *KAMAL.proxy.reset_image_version, raise_on_non_zero_exit: false
       end
     else
       raise ArgumentError, "Unknown boot_config subcommand #{subcommand}"

lib/kamal/commands/base.rb

@@ -68,6 +68,10 @@ module Kamal::Commands
         combine *commands, by: "||"
       end
 
+      def substitute(*commands)
+        "\$\(#{commands.join(" ")}\)"
+      end
+
       def xargs(command)
         [ :xargs, command ].flatten
       end

lib/kamal/commands/proxy.rb

@@ -2,7 +2,7 @@ class Kamal::Commands::Proxy < Kamal::Commands::Base
   delegate :argumentize, :optionize, to: Kamal::Utils
 
   def run
-    pipe echo_boot_config, xargs(docker_run)
+    pipe boot_config, xargs(docker_run)
   end
 
   def start
@@ -24,7 +24,7 @@ class Kamal::Commands::Proxy < Kamal::Commands::Base
   def version
     pipe \
       docker(:inspect, container_name, "--format '{{.Config.Image}}'"),
-      [ :cut, "-d:", "-f2" ]
+      [ :awk, "-F:", "'{print \$NF}'" ]
   end
 
   def logs(timestamps: true, since: nil, lines: nil, grep: nil, grep_options: nil)
@@ -65,21 +65,41 @@ class Kamal::Commands::Proxy < Kamal::Commands::Base
     remove_directory config.proxy_directory
   end
 
-  def get_boot_options
-    combine [ :cat, config.proxy_options_file, "2>", "/dev/null" ], [ :echo, "\"#{config.proxy_options_default.join(" ")}\"" ], by: "||"
+  def boot_config
+    [ :echo, "#{substitute(read_boot_options)} #{substitute(read_image)}:#{substitute(read_image_version)}" ]
+  end
+
+  def read_boot_options
+    read_file(config.proxy_options_file, default: config.proxy_options_default.join(" "))
+  end
+
+  def read_image
+    read_file(config.proxy_image_file, default: config.proxy_image_default)
+  end
+
+  def read_image_version
+    read_file(config.proxy_image_version_file, default: Kamal::Configuration::PROXY_MINIMUM_VERSION)
   end
 
   def reset_boot_options
     remove_file config.proxy_options_file
   end
 
+  def reset_image
+    remove_file config.proxy_image_file
+  end
+
+  def reset_image_version
+    remove_file config.proxy_image_version_file
+  end
+
   private
     def container_name
       config.proxy_container_name
     end
 
-    def echo_boot_config
-      [ :echo, "\$\(#{get_boot_options.join(" ")}\) #{config.proxy_image}" ]
+    def read_file(file, default: nil)
+      combine [ :cat, file, "2>", "/dev/null" ], [ :echo, "\"#{default}\"" ], by: "||"
     end
 
     def docker_run

lib/kamal/configuration.rb

@@ -261,8 +261,16 @@ class Kamal::Configuration
     [ *proxy_publish_args(PROXY_HTTP_PORT, PROXY_HTTPS_PORT), *proxy_logging_args(PROXY_LOG_MAX_SIZE) ]
   end
 
-  def proxy_image
-    "basecamp/kamal-proxy:#{PROXY_MINIMUM_VERSION}"
+  def proxy_repository_name
+    "basecamp"
+  end
+
+  def proxy_image_name
+    "kamal-proxy"
+  end
+
+  def proxy_image_default
+    "#{proxy_repository_name}/#{proxy_image_name}"
   end
 
   def proxy_container_name
@@ -277,6 +285,14 @@ class Kamal::Configuration
     File.join proxy_directory, "options"
   end
 
+  def proxy_image_file
+    File.join proxy_directory, "image"
+  end
+
+  def proxy_image_version_file
+    File.join proxy_directory, "image_version"
+  end
+
   def to_h
     {
       roles: role_names,