Add proxy boot_config --publish-ip argument

lib/kamal/cli/proxy.rb

@@ -23,6 +23,7 @@ def boot
 
   desc "boot_config <set|get|reset>", "Manage kamal-proxy boot configuration"
   option :publish, type: :boolean, default: true, desc: "Publish the proxy ports on the host"
+  option :publish_host_ip, type: :string, repeatable: true, default: nil, desc: "Host IP address to bind HTTP/HTTPS traffic to. Defaults to all interfaces"
   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"
@@ -31,7 +32,7 @@ def boot_config(subcommand)
     case subcommand
     when "set"
       boot_options = [
-        *(KAMAL.config.proxy_publish_args(options[:http_port], options[:https_port]) if options[:publish]),
+        *(KAMAL.config.proxy_publish_args(options[:http_port], options[:https_port], options[:publish_host_ip]) if options[:publish]),
         *(KAMAL.config.proxy_logging_args(options[:log_max_size])),
         *options[:docker_options].map { |option| "--#{option}" }
       ]

lib/kamal/configuration.rb

@@ -249,8 +249,16 @@ def env_tag(name)
     env_tags.detect { |t| t.name == name.to_s }
   end
 
-  def proxy_publish_args(http_port, https_port)
-    argumentize "--publish", [ "#{http_port}:#{PROXY_HTTP_PORT}", "#{https_port}:#{PROXY_HTTPS_PORT}" ]
+  def proxy_publish_args(http_port, https_port, bind_ips = nil)
+    ensure_valid_bind_ips(bind_ips)
+
+    (bind_ips || [ nil ]).map do |bind_ip|
+      bind_ip = format_bind_ip(bind_ip)
+      publish_http = [ bind_ip, http_port, PROXY_HTTP_PORT ].compact.join(":")
+      publish_https = [ bind_ip, https_port, PROXY_HTTPS_PORT ].compact.join(":")
+
+      argumentize "--publish", [ publish_http, publish_https ]
+    end.join(" ")
   end
 
   def proxy_logging_args(max_size)
@@ -344,6 +352,15 @@ def ensure_valid_kamal_version
       true
     end
 
+    def ensure_valid_bind_ips(bind_ips)
+      bind_ips.present? && bind_ips.each do |ip|
+        next if ip =~ Resolv::IPv4::Regex || ip =~ Resolv::IPv6::Regex
+        raise ArgumentError, "Invalid publish IP address: #{ip}"
+      end
+
+      true
+    end
+
     def ensure_retain_containers_valid
       raise Kamal::ConfigurationError, "Must retain at least 1 container" if retain_containers < 1
 
@@ -375,6 +392,15 @@ def ensure_unique_hosts_for_ssl_roles
       true
     end
 
+    def format_bind_ip(ip)
+      # Ensure IPv6 address inside square brackets - e.g. [::1]
+      if ip =~ Resolv::IPv6::Regex && ip !~ /\[.*\]/
+        "[#{ip}]"
+      else
+        ip
+      end
+    end
+
     def role_names
       raw_config.servers.is_a?(Array) ? [ "web" ] : raw_config.servers.keys.sort
     end

test/cli/proxy_test.rb

@@ -281,6 +281,32 @@ class CliProxyTest < CliTestCase
     end
   end
 
+  test "boot_config set bind IP" do
+    run_command("boot_config", "set", "--publish-host-ip", "127.0.0.1").tap do |output|
+      %w[ 1.1.1.1 1.1.1.2 ].each do |host|
+        assert_match "Running /usr/bin/env mkdir -p .kamal/proxy on #{host}", output
+        assert_match "Uploading \"--publish 127.0.0.1:80:80 --publish 127.0.0.1:443:443 --log-opt max-size=10m\" to .kamal/proxy/options on #{host}", output
+      end
+    end
+  end
+
+  test "boot_config set multiple bind IPs" do
+    run_command("boot_config", "set", "--publish-host-ip", "127.0.0.1", "--publish-host-ip", "::1").tap do |output|
+      %w[ 1.1.1.1 1.1.1.2 ].each do |host|
+        assert_match "Running /usr/bin/env mkdir -p .kamal/proxy on #{host}", output
+        assert_match "Uploading \"--publish 127.0.0.1:80:80 --publish 127.0.0.1:443:443 --publish [::1]:80:80 --publish [::1]:443:443 --log-opt max-size=10m\" to .kamal/proxy/options on #{host}", output
+      end
+    end
+  end
+
+  test "boot_config set invalid bind IPs" do
+    exception = assert_raises do
+      run_command("boot_config", "set", "--publish-host-ip", "1.2.3.invalidIP", "--publish-host-ip", "::1")
+    end
+
+    assert_includes exception.message, "Invalid publish IP address: 1.2.3.invalidIP"
+  end
+
   test "boot_config set docker options" do
     run_command("boot_config", "set", "--docker_options", "label=foo=bar", "add_host=thishost:thathost").tap do |output|
       %w[ 1.1.1.1 1.1.1.2 ].each do |host|