Use kamal network for containers

Create a `kamal` network for the proxy and app containers to run in.
This allows the proxy to refer to the app containers by name.

lib/kamal/cli/app.rb

@@ -41,8 +41,7 @@ class Kamal::Cli::App < Kamal::Cli::Base
 
           if role.running_proxy?
             version = capture_with_info(*app.current_running_version, raise_on_non_zero_exit: false).strip
-            ip = capture_with_info(*app.internal_ip(version: version), raise_on_non_zero_exit: false).strip
-            execute *KAMAL.proxy.deploy(ip)
+            execute *KAMAL.proxy.deploy(app.container_name(version))
           end
         end
       end
@@ -60,12 +59,12 @@ class Kamal::Cli::App < Kamal::Cli::Base
           version = capture_with_info(*app.current_running_version, raise_on_non_zero_exit: false).strip
 
           execute *KAMAL.auditor.record("Stopped app", role: role), verbosity: :debug
-          execute *app.stop, raise_on_non_zero_exit: false
 
           if role.running_proxy?
-            ip = capture_with_info(*app.internal_ip(version: version), raise_on_non_zero_exit: false).strip
-            execute *KAMAL.proxy.remove(ip), raise_on_non_zero_exit: false
+            execute *KAMAL.proxy.remove(app.container_name(version)), raise_on_non_zero_exit: false
           end
+
+          execute *app.stop, raise_on_non_zero_exit: false
         end
       end
     end

lib/kamal/cli/app/boot.rb

@@ -48,8 +48,7 @@ class Kamal::Cli::App::Boot
       audit "Booted app version #{version}"
       execute *app.run(hostname: "#{host}-#{SecureRandom.hex(6)}")
       if running_proxy?
-        ip = capture_with_info(*app.internal_ip(version: version), raise_on_non_zero_exit: false).strip
-        execute *KAMAL.proxy.deploy(ip)
+        execute *KAMAL.proxy.deploy(app.container_name(version))
       end
     end
 

lib/kamal/cli/server.rb

@@ -14,6 +14,14 @@ class Kamal::Cli::Server < Kamal::Cli::Base
       end
 
       execute(*KAMAL.server.ensure_run_directory)
+
+      begin
+        execute(*KAMAL.docker.create_kamal_network)
+      rescue SSHKit::Command::Failed => e
+        if e.message !~ /network with name kamal already exists/
+          raise
+        end
+      end
     end
 
     if missing.any?

lib/kamal/commands/app.rb

@@ -15,6 +15,7 @@ class Kamal::Commands::App < Kamal::Commands::Base
       "--detach",
       "--restart unless-stopped",
       "--name", container_name,
+      "--network kamal",
       *([ "--hostname", hostname ] if hostname),
       "-e", "KAMAL_CONTAINER_NAME=\"#{container_name}\"",
       "-e", "KAMAL_VERSION=\"#{config.version}\"",
@@ -43,10 +44,6 @@ class Kamal::Commands::App < Kamal::Commands::Base
       xargs(config.stop_wait_time ? docker(:stop, "-t", config.stop_wait_time) : docker(:stop))
   end
 
-  def internal_ip(version: nil)
-    docker :inspect, "--format '{{ .NetworkSettings.IPAddress }}'", container_name(version)
-  end
-
   def info
     docker :ps, *filter_args
   end
@@ -60,6 +57,10 @@ class Kamal::Commands::App < Kamal::Commands::Base
     container_id_for(container_name: container_name(version), only_running: only_running)
   end
 
+  def container_name(version = nil)
+    [ role.container_prefix, version || config.version ].compact.join("-")
+  end
+
   def current_running_version
     list_versions("--latest", statuses: ACTIVE_DOCKER_STATUSES)
   end
@@ -81,10 +82,6 @@ class Kamal::Commands::App < Kamal::Commands::Base
 
 
   private
-    def container_name(version = nil)
-      [ role.container_prefix, version || config.version ].compact.join("-")
-    end
-
     def filter_args(statuses: nil)
       argumentize "--filter", filters(statuses: statuses)
     end

lib/kamal/commands/docker.rb

@@ -19,6 +19,10 @@ class Kamal::Commands::Docker < Kamal::Commands::Base
     [ '[ "${EUID:-$(id -u)}" -eq 0 ] || command -v sudo >/dev/null || command -v su >/dev/null' ]
   end
 
+  def create_kamal_network
+    docker :network, :create, :kamal
+  end
+
   private
     def get_docker
       shell \

lib/kamal/commands/proxy.rb

@@ -10,6 +10,7 @@ class Kamal::Commands::Proxy < Kamal::Commands::Base
       "--name", container_name,
       "--detach",
       "--restart", "unless-stopped",
+      "--network kamal",
       *publish_args,
       "--volume", "/var/run/docker.sock:/var/run/docker.sock",
       *config.logging_args,