Configurable Healthcheck Expose Port

lib/kamal/commands/healthcheck.rb

@@ -1,5 +1,4 @@
 class Kamal::Commands::Healthcheck < Kamal::Commands::Base
-  EXPOSED_PORT = 3999
 
   def run
     web = config.role(:web)
@@ -7,7 +6,7 @@ class Kamal::Commands::Healthcheck < Kamal::Commands::Base
     docker :run,
       "--detach",
       "--name", container_name_with_version,
-      "--publish", "#{EXPOSED_PORT}:#{config.healthcheck["port"]}",
+      "--publish", "#{exposed_port}:#{config.healthcheck["port"]}",
       "--label", "service=#{container_name}",
       "-e", "KAMAL_CONTAINER_NAME=\"#{container_name}\"",
       *web.env_args,
@@ -52,6 +51,10 @@ class Kamal::Commands::Healthcheck < Kamal::Commands::Base
     end
 
     def health_url
-      "http://localhost:#{EXPOSED_PORT}#{config.healthcheck["path"]}"
+      "http://localhost:#{exposed_port}#{config.healthcheck["path"]}"
+    end
+
+    def exposed_port
+      config.healthcheck["exposed_port"]
     end
 end

lib/kamal/configuration.rb

@@ -145,7 +145,7 @@ class Kamal::Configuration
 
 
   def healthcheck
-    { "path" => "/up", "port" => 3000, "max_attempts" => 7 }.merge(raw_config.healthcheck || {})
+    { "path" => "/up", "port" => 3000, "max_attempts" => 7, "exposed_port" => 3999 }.merge(raw_config.healthcheck || {})
   end
 
   def readiness_delay

test/commands/healthcheck_test.rb

@@ -40,8 +40,9 @@ class CommandsHealthcheckTest < ActiveSupport::TestCase
 
   test "run with custom options" do
     @config[:servers] = { "web" => { "hosts" => [ "1.1.1.1" ], "options" => { "mount" => "somewhere" } } }
+    @config[:healthcheck] = { "exposed_port" => 4999 }
     assert_equal \
-      "docker run --detach --name healthcheck-app-123 --publish 3999:3000 --label service=healthcheck-app -e KAMAL_CONTAINER_NAME=\"healthcheck-app\" --health-cmd \"curl -f http://localhost:3000/up || exit 1\" --health-interval \"1s\" --mount \"somewhere\" dhh/app:123",
+      "docker run --detach --name healthcheck-app-123 --publish 4999:3000 --label service=healthcheck-app -e KAMAL_CONTAINER_NAME=\"healthcheck-app\" --health-cmd \"curl -f http://localhost:3000/up || exit 1\" --health-interval \"1s\" --mount \"somewhere\" dhh/app:123",
       new_command.run.join(" ")
   end