Allow kamal-proxy run command options to be set

Allow --metrics_port and --debug options to be set via the boot config.

--metrics_port support will come in kamal-proxy v0.8.8, so this option
doesn't work right now.

This will be updated before the next Kamal release though and we can add
integration tests for the metrics at that point.

lib/kamal/cli/proxy.rb

@@ -31,6 +31,8 @@ class Kamal::Cli::Proxy < Kamal::Cli::Base
   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 :metrics_port, type: :numeric, default: nil, desc: "Port to report prometheus metrics on"
+  option :debug, type: :boolean, default: false, desc: "Whether to run the proxy in debug mode"
   option :docker_options, type: :array, default: [], desc: "Docker options to pass to the proxy container", banner: "option=value option2=value2"
   def boot_config(subcommand)
     proxy_boot_config = KAMAL.config.proxy_boot
@@ -51,6 +53,9 @@ class Kamal::Cli::Proxy < Kamal::Cli::Base
 
       image_version = options[:image_version]
 
+      run_command_options = { debug: options[:debug] || nil, "metrics-port": options[:metrics_port] }.compact
+      run_command = "kamal-proxy run #{Kamal::Utils.optionize(run_command_options).join(" ")}" if run_command_options.any?
+
       on(KAMAL.proxy_hosts) do |host|
         execute(*KAMAL.proxy.ensure_proxy_directory)
         if boot_options != proxy_boot_config.default_boot_options
@@ -70,6 +75,12 @@ class Kamal::Cli::Proxy < Kamal::Cli::Base
         else
           execute *KAMAL.proxy.reset_image_version, raise_on_non_zero_exit: false
         end
+
+        if run_command
+          upload! StringIO.new(run_command), KAMAL.config.proxy_run_command_file
+        else
+          execute *KAMAL.proxy.reset_run_command, raise_on_non_zero_exit: false
+        end
       end
     when "get"
 
@@ -81,6 +92,7 @@ class Kamal::Cli::Proxy < Kamal::Cli::Base
         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
+        execute *KAMAL.proxy.reset_run_command, raise_on_non_zero_exit: false
       end
     else
       raise ArgumentError, "Unknown boot_config subcommand #{subcommand}"

lib/kamal/commands/proxy.rb

@@ -70,7 +70,7 @@ class Kamal::Commands::Proxy < Kamal::Commands::Base
   end
 
   def boot_config
-    [ :echo, "#{substitute(read_boot_options)} #{substitute(read_image)}:#{substitute(read_image_version)}" ]
+    [ :echo, "#{substitute(read_boot_options)} #{substitute(read_image)}:#{substitute(read_image_version)} #{substitute(read_run_command)}" ]
   end
 
   def read_boot_options
@@ -85,6 +85,10 @@ class Kamal::Commands::Proxy < Kamal::Commands::Base
     read_file(config.proxy_boot.image_version_file, default: Kamal::Configuration::Proxy::Boot::MINIMUM_VERSION)
   end
 
+  def read_run_command
+    read_file(config.proxy_run_command_file)
+  end
+
   def reset_boot_options
     remove_file config.proxy_boot.options_file
   end
@@ -97,6 +101,10 @@ class Kamal::Commands::Proxy < Kamal::Commands::Base
     remove_file config.proxy_boot.image_version_file
   end
 
+  def reset_run_command
+    remove_file config.proxy_run_command_file
+  end
+
   private
     def container_name
       config.proxy_boot.container_name