Minimise holding the deploy lock

If we get an error we'll only hold the deploy lock if it occurs while
trying to switch the running containers.

We'll also move tagging the latest image from when the image is pulled
to just before the container switch. This ensures that earlier errors
don't leave the hosts with an updated latest tag while still running the
older version.

test/cli/app_test.rb

@@ -6,6 +6,7 @@ class CliAppTest < CliTestCase
     SSHKit::Backend::Abstract.any_instance.stubs(:capture).returns("123") # old version
 
     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 container ls --all --filter name=^app-web-123$ --quiet | xargs docker stop", output
     end

test/cli/build_test.rb

@@ -30,7 +30,7 @@ class CliBuildTest < CliTestCase
   test "pull" do
     run_command("pull").tap do |output|
       assert_match /docker image rm --force dhh\/app:999/, output
-      assert_match /docker pull dhh\/app:latest/, output
+      assert_match /docker pull dhh\/app:999/, output
     end
   end
 

test/cli/main_test.rb

@@ -79,18 +79,35 @@ class CliMainTest < CliTestCase
     end
   end
 
-  test "deploy errors leave lock in place" do
+  test "deploy errors during critical section leave lock in place" do
+    invoke_options = { "config_file" => "test/fixtures/deploy_simple.yml", "skip_broadcast" => false, "version" => "999" }
+
+    Mrsk::Cli::Main.any_instance.expects(:invoke).with("mrsk:cli:server:bootstrap", [], invoke_options)
+    Mrsk::Cli::Main.any_instance.expects(:invoke).with("mrsk:cli:registry:login", [], invoke_options)
+    Mrsk::Cli::Main.any_instance.expects(:invoke).with("mrsk:cli:build:deliver", [], invoke_options)
+    Mrsk::Cli::Main.any_instance.expects(:invoke).with("mrsk:cli:traefik:boot", [], invoke_options)
+    Mrsk::Cli::Main.any_instance.expects(:invoke).with("mrsk:cli:healthcheck:perform", [], invoke_options)
+    Mrsk::Cli::Main.any_instance.expects(:invoke).with("mrsk:cli:app:boot", [], invoke_options).raises(RuntimeError)
+
+    assert !MRSK.holding_lock?
+    assert_raises(RuntimeError) do
+      stderred { run_command("deploy") }
+    end
+    assert MRSK.holding_lock?
+  end
+
+  test "deploy errors during outside section leave remove lock" do
     invoke_options = { "config_file" => "test/fixtures/deploy_simple.yml", "skip_broadcast" => false, "version" => "999" }
 
     Mrsk::Cli::Main.any_instance.expects(:invoke)
       .with("mrsk:cli:server:bootstrap", [], invoke_options)
       .raises(RuntimeError)
 
-    assert_equal 0, MRSK.lock_count
+    assert !MRSK.holding_lock?
     assert_raises(RuntimeError) do
       stderred { run_command("deploy") }
     end
-    assert_equal 1, MRSK.lock_count
+    assert !MRSK.holding_lock?
   end
 
   test "redeploy" do
@@ -136,6 +153,7 @@ class CliMainTest < CliTestCase
 
     run_command("rollback", "123", config_file: "deploy_with_accessories").tap do |output|
       assert_match "Start version 123", output
+      assert_match "docker tag dhh/app:123 dhh/app:latest", output
       assert_match "docker start app-web-123", output
       assert_match "docker container ls --all --filter name=^app-web-version-to-rollback$ --quiet | xargs docker stop", output, "Should stop the container that was previously running"
     end

test/commands/app_test.rb

@@ -267,6 +267,12 @@ class CommandsAppTest < ActiveSupport::TestCase
       new_command.remove_images.join(" ")
   end
 
+  test "tag_current_as_latest" do
+    assert_equal \
+      "docker tag dhh/app:999 dhh/app:latest",
+      new_command.tag_current_as_latest.join(" ")
+  end
+
   private
     def new_command(role: "web")
       Mrsk::Commands::App.new(Mrsk::Configuration.new(@config, destination: @destination, version: "999"), role: role)