Prevents last good release from being deleted on cleanup (#1922)

* Prevents last good release from being deleted on cleanup

Issue: 1907

If there are many failed deployments the relese folders will
still be left there and eventually if deploy:cleanup is
executed it will delete the release that is referenced by the
"current" symlink, potentially causing downtime.

That change will prevent the "current release" from ever being
removed during cleanup.

* Link PR on CHANGELOG

* Verify if current dir exists

Check if current release directory exists instead of relying on
exceptions being raised.

CHANGELOG.md

@@ -19,6 +19,7 @@ gem "capistrano", :github => "capistrano/capistrano"
 [master]: https://github.com/capistrano/capistrano/compare/v3.9.1...HEAD
 
 * Your contribution here!
+* [#1922](https://github.com/capistrano/capistrano/pull/1922): Prevents last good release from being deleted during cleanup if there are too many subsequent failed deploys
 * As of this release, version 2.x of Capistrano is officially End of Life. No further releases of 2.x series are planned, and pull requests against 2.x are no longer accepted. The maintainers encourage you to upgrade to 3.x if possible.
 * [#1937](https://github.com/capistrano/capistrano/pull/1937): Clarify error message when plugin is required in the wrong config file.
 * [#1930](https://github.com/capistrano/capistrano/issues/1930): Default to locking the version using the pessimistic version operator at the patch level.

features/deploy.feature

@@ -60,6 +60,16 @@ Feature: Deploy
     Then 3 valid releases are kept
     And the invalid "new" release is ignored
 
+  Scenario: Cleanup after many failed releases doesn't remove last good release
+    Given config stage file has line "set :keep_releases, 2"
+    And I make 2 deployments
+    And an invalid release named "77777777777777"
+    And an invalid release named "88888888888888"
+    And an invalid release named "99999999999999"
+    When I run cap "deploy:cleanup"
+    Then 3 valid releases are kept
+    And the current directory will be a symlink to the release
+
   Scenario: Rolling Back
     Given I make 2 deployments
     When I run cap "deploy:rollback"

features/step_definitions/assertions.rb

@@ -66,7 +66,7 @@ Then(/^directory symlinks are created in the new release$/) do
 end
 
 Then(/^the current directory will be a symlink to the release$/) do
-  run_vagrant_command(test_symlink_exists(TestApp.current_path))
+  run_vagrant_command(exists?("e", TestApp.current_path))
 end
 
 Then(/^the deploy\.rb file is created$/) do

lib/capistrano/i18n.rb

@@ -14,6 +14,8 @@ en = {
   question_default: "Please enter %{key} (%{default_value}): ",
   keeping_releases: "Keeping %{keep_releases} of %{releases} deployed releases on %{host}",
   skip_cleanup: "Skipping cleanup of invalid releases on %{host}; unexpected foldername found (should be timestamp)",
+  wont_delete_current_release: "Current release was marked for being removed but it's going to be skipped on %{host}",
+  no_current_release: "There is no current release present on %{host}",
   no_old_releases: "No old releases (keeping newest %{keep_releases}) on %{host}",
   linked_file_does_not_exist: "linked file %{file} does not exist on %{host}",
   cannot_rollback: "There are no older releases to rollback to",

lib/capistrano/tasks/deploy.rake

@@ -155,11 +155,20 @@ namespace :deploy do
 
       if valid.count >= fetch(:keep_releases)
         info t(:keeping_releases, host: host.to_s, keep_releases: fetch(:keep_releases), releases: valid.count)
-        directories = (valid - valid.last(fetch(:keep_releases)))
+        directories = (valid - valid.last(fetch(:keep_releases))).map do |release|
+          releases_path.join(release).to_s
+        end
+        if test("[ -d #{current_path} ]")
+          current_release = capture(:readlink, current_path).to_s
+          if directories.include?(current_release)
+            warn t(:wont_delete_current_release, host: host.to_s)
+            directories.delete(current_release)
+          end
+        else
+          debug t(:no_current_release, host: host.to_s)
+        end
         if directories.any?
-          directories_str = directories.map do |release|
-            releases_path.join(release)
-          end.join(" ")
+          directories_str = directories.join(" ")
           execute :rm, "-rf", directories_str
         else
           info t(:no_old_releases, host: host.to_s, keep_releases: fetch(:keep_releases))