Adapted install/uninstall/list PluginManager's command to respect the alised plugins (#12821) (#12836)

Adapted install/uninstall/list PluginManager's CLI commands to respect the alised plugins
- adapt install plugin to resolve an alias giving precedence on a real plugin
- changed list to mark alised plugins
- uninstall avoid to remove the alias and ask the user to remove the original plugin
- update update the original plugin in case of alias, else fallback on usual behavior

Co-authored-by: Ry Biesemeyer <ry.biesemeyer@elastic.co>
(cherry picked from commit 1e08341e1e)

lib/pluginmanager/install.rb

@@ -70,7 +70,7 @@ class LogStash::PluginManager::Install < LogStash::PluginManager::Command
       gems = plugins_development_gems
     else
       gems = plugins_gems
-      verify_remote!(gems) if !local? && verify?
+      gems = verify_remote!(gems) if !local? && verify?
     end
 
     check_for_integrations(gems)
@@ -123,12 +123,30 @@ class LogStash::PluginManager::Install < LogStash::PluginManager::Command
   # Check if the specified gems contains
   # the logstash `metadata`
   def verify_remote!(gems)
+    gems_swap = {}
     options = { :rubygems_source => gemfile.gemset.sources }
     gems.each do |plugin, version|
       puts("Validating #{[plugin, version].compact.join("-")}")
       next if validate_plugin(plugin, version, options)
+
+      signal_usage_error("Installs of an alias doesn't require version specification --version") if version
+
+      # if the plugin is an alias then fallback to the original name
+      if LogStash::PluginManager::ALIASES.has_key?(plugin)
+        resolved_plugin = LogStash::PluginManager::ALIASES[plugin]
+        if validate_plugin(resolved_plugin, version, options)
+          puts "Remapping alias #{plugin} to #{resolved_plugin}"
+          gems_swap[plugin] = resolved_plugin
+          next
+        end
+      end
       signal_error("Installation aborted, verification failed for #{plugin} #{version}")
     end
+
+    # substitute in gems the list the alias plugin with the original
+    gems.collect do |plugin, version|
+      [gems_swap.fetch(plugin, plugin), version]
+    end
   end
 
   def validate_plugin(plugin, version, options)

lib/pluginmanager/list.rb

@@ -34,10 +34,16 @@ class LogStash::PluginManager::List < LogStash::PluginManager::Command
 
     signal_error("No plugins found") if filtered_specs.empty?
 
+    installed_plugin_names = filtered_specs.collect {|spec| spec.name}
+
     filtered_specs.sort_by{|spec| spec.name}.each do |spec|
       line = "#{spec.name}"
       line += " (#{spec.version})" if verbose?
       puts(line)
+      if LogStash::PluginManager::ALIASES.has_value?(spec.name)
+        alias_plugin = LogStash::PluginManager::ALIASES.key(spec.name)
+        puts("└── #{alias_plugin} (alias)") unless installed_plugin_names.include?(alias_plugin)
+      end
       if spec.metadata.fetch("logstash_group", "") == "integration"
         integration_plugins = spec.metadata.fetch("integration_plugins", "").split(",")
         integration_plugins.each_with_index do |integration_plugin, i|

lib/pluginmanager/remove.rb

@@ -32,6 +32,14 @@ class LogStash::PluginManager::Remove < LogStash::PluginManager::Command
     ##
     LogStash::Bundler.setup!({:without => [:build, :development]})
 
+    if LogStash::PluginManager::ALIASES.has_key?(plugin)
+      unless LogStash::PluginManager.installed_plugin?(plugin, gemfile)
+        aliased_plugin = LogStash::PluginManager::ALIASES[plugin]
+        puts "Cannot remove the alias #{plugin}, which is an alias for #{aliased_plugin}; if you wish to remove it, you must remove the aliased plugin instead."
+        return
+      end
+    end
+
     # If a user is attempting to uninstall X-Pack, present helpful output to guide
     # them toward the OSS-only distribution of Logstash
     LogStash::PluginManager::XPackInterceptor::Remove.intercept!(plugin)

lib/pluginmanager/update.rb

@@ -63,6 +63,7 @@ class LogStash::PluginManager::Update < LogStash::PluginManager::Command
     # remove any version constrain from the Gemfile so the plugin(s) can be updated to latest version
     # calling update without requirements will remove any previous requirements
     plugins = plugins_to_update(previous_gem_specs_map)
+
     # Skipping the major version validation when using a local cache as we can have situations
     # without internet connection.
     filtered_plugins = plugins.map { |plugin| gemfile.find(plugin) }
@@ -99,9 +100,25 @@ class LogStash::PluginManager::Update < LogStash::PluginManager::Command
       # If the plugins isn't available in the gemspec or in 
       # the gemfile defined with a local path, we assume the plugins is not
       # installed.
-      not_installed = plugins_arg.select{|plugin| !previous_gem_specs_map.has_key?(plugin.downcase) && !gemfile.find(plugin) }
+      not_installed = plugins_arg.select { |plugin| !previous_gem_specs_map.has_key?(plugin.downcase) && !gemfile.find(plugin) }
+
+      # find only the not installed that doesn't correspond to an alias
+      not_installed_aliases = not_installed.select { |plugin| LogStash::PluginManager::ALIASES.has_key?(plugin)}
+      not_installed -= not_installed_aliases
+
       signal_error("Plugin #{not_installed.join(', ')} is not installed so it cannot be updated, aborting") unless not_installed.empty?
-      plugins_arg
+
+      # resolve aliases that doesn't correspond to a real gem
+      plugins_to_update = plugins_arg.map do |plugin|
+        if not_installed_aliases.include?(plugin)
+          resolved_plugin = LogStash::PluginManager::ALIASES[plugin]
+          puts "Remapping alias #{plugin} to #{resolved_plugin}"
+          resolved_plugin
+        else
+          plugin
+        end
+      end
+      plugins_to_update
     end
   end
 

lib/pluginmanager/util.rb

@@ -20,6 +20,9 @@ require_relative "../bootstrap/patches/remote_fetcher"
 
 module LogStash::PluginManager
 
+  # Defines the plugin alias, must be kept in synch with Java class org.logstash.plugins.AliasRegistry
+  ALIASES = {"logstash-input-elastic_agent" => "logstash-input-beats"}
+
   class ValidationError < StandardError; end
 
   # check for valid logstash plugin gem name & version or .gem file, logs errors to $stdout