Prefix container hostname with the underlying one

To make it easier to identity where a docker container is running,
prefix its hostname with the underlying one from the host.

Docker chooses a 12 character random hex string by default, so we'll
keep that as the suffix.

lib/mrsk/cli/app.rb

@@ -29,7 +29,7 @@ class Mrsk::Cli::App < Mrsk::Cli::Base
               execute *auditor.record("Booted app version #{version}"), verbosity: :debug
 
               old_version = capture_with_info(*app.current_running_version, raise_on_non_zero_exit: false).strip
-              execute *app.start_or_run
+              execute *app.start_or_run(hostname: "#{host}-#{SecureRandom.hex(6)}")
 
               Mrsk::Utils::HealthcheckPoller.wait_for_healthy(pause_after_ready: true) { capture_with_info(*app.status(version: version)) }
 

lib/mrsk/commands/app.rb

@@ -8,17 +8,18 @@ class Mrsk::Commands::App < Mrsk::Commands::Base
     @role = role
   end
 
-  def start_or_run
-    combine start, run, by: "||"
+  def start_or_run(hostname: nil)
+    combine start, run(hostname: hostname), by: "||"
   end
 
-  def run
+  def run(hostname: nil)
     role = config.role(self.role)
 
     docker :run,
       "--detach",
       "--restart unless-stopped",
       "--name", container_name,
+      *(["--hostname", hostname] if hostname),
       "-e", "MRSK_CONTAINER_NAME=\"#{container_name}\"",
       *role.env_args,
       *role.health_check_args,

test/cli/app_test.rb

@@ -5,7 +5,7 @@ class CliAppTest < CliTestCase
     stub_running
     run_command("boot").tap do |output|
       assert_match "docker tag dhh/app:latest dhh/app:latest", output
-      assert_match "docker run --detach --restart unless-stopped", output
+      assert_match /docker run --detach --restart unless-stopped --name app-web-latest --hostname 1.1.1.1-[0-9a-f]{12} /, output
       assert_match "docker container ls --all --filter name=^app-web-123$ --quiet | xargs docker stop", output
     end
   end
@@ -28,7 +28,7 @@ class CliAppTest < CliTestCase
     run_command("boot").tap do |output|
       assert_match /Renaming container .* to .* as already deployed on 1.1.1.1/, output # Rename
       assert_match /docker rename app-web-latest app-web-latest_replaced_[0-9a-f]{16}/, output
-      assert_match "docker run --detach --restart unless-stopped", output
+      assert_match /docker run --detach --restart unless-stopped --name app-web-latest --hostname 1.1.1.1-[0-9a-f]{12} /, output
       assert_match "docker container ls --all --filter name=^app-web-123$ --quiet | xargs docker stop", output
     end
   ensure

test/commands/app_test.rb

@@ -17,6 +17,12 @@ class CommandsAppTest < ActiveSupport::TestCase
       new_command.run.join(" ")
   end
 
+  test "run with hostname" do
+    assert_equal \
+      "docker run --detach --restart unless-stopped --name app-web-999 --hostname myhost -e MRSK_CONTAINER_NAME=\"app-web-999\" -e RAILS_MASTER_KEY=\"456\" --health-cmd \"curl -f http://localhost:3000/up || exit 1\" --health-interval \"1s\" --log-opt max-size=\"10m\" --label service=\"app\" --label role=\"web\" --label traefik.http.services.app-web.loadbalancer.server.scheme=\"http\" --label traefik.http.routers.app-web.rule=\"PathPrefix(\\`/\\`)\" --label traefik.http.middlewares.app-web-retry.retry.attempts=\"5\" --label traefik.http.middlewares.app-web-retry.retry.initialinterval=\"500ms\" --label traefik.http.routers.app-web.middlewares=\"app-web-retry@docker\" dhh/app:999",
+      new_command.run(hostname: "myhost").join(" ")
+  end
+
   test "run with volumes" do
     @config[:volumes] = ["/local/path:/container/path" ]
 
@@ -77,6 +83,18 @@ class CommandsAppTest < ActiveSupport::TestCase
       new_command.start.join(" ")
   end
 
+  test "start_or_run" do
+    assert_equal \
+      "docker start app-web-999 || docker run --detach --restart unless-stopped --name app-web-999 -e MRSK_CONTAINER_NAME=\"app-web-999\" -e RAILS_MASTER_KEY=\"456\" --health-cmd \"curl -f http://localhost:3000/up || exit 1\" --health-interval \"1s\" --log-opt max-size=\"10m\" --label service=\"app\" --label role=\"web\" --label traefik.http.services.app-web.loadbalancer.server.scheme=\"http\" --label traefik.http.routers.app-web.rule=\"PathPrefix(\\`/\\`)\" --label traefik.http.middlewares.app-web-retry.retry.attempts=\"5\" --label traefik.http.middlewares.app-web-retry.retry.initialinterval=\"500ms\" --label traefik.http.routers.app-web.middlewares=\"app-web-retry@docker\" dhh/app:999",
+      new_command.start_or_run.join(" ")
+  end
+
+  test "start_or_run with hostname" do
+    assert_equal \
+      "docker start app-web-999 || docker run --detach --restart unless-stopped --name app-web-999 --hostname myhost -e MRSK_CONTAINER_NAME=\"app-web-999\" -e RAILS_MASTER_KEY=\"456\" --health-cmd \"curl -f http://localhost:3000/up || exit 1\" --health-interval \"1s\" --log-opt max-size=\"10m\" --label service=\"app\" --label role=\"web\" --label traefik.http.services.app-web.loadbalancer.server.scheme=\"http\" --label traefik.http.routers.app-web.rule=\"PathPrefix(\\`/\\`)\" --label traefik.http.middlewares.app-web-retry.retry.attempts=\"5\" --label traefik.http.middlewares.app-web-retry.retry.initialinterval=\"500ms\" --label traefik.http.routers.app-web.middlewares=\"app-web-retry@docker\" dhh/app:999",
+      new_command.start_or_run(hostname: "myhost").join(" ")
+  end
+
   test "stop" do
     assert_equal \
       "docker ps --quiet --filter label=service=app --filter label=role=web --filter status=running --filter status=restarting --latest | xargs docker stop",