Merge pull request #4709 from BaronGreenback/PluginDowngrade

(cherry picked from commit 406ae3e43a20216292c554151fa2d0e2a09edfa3)
Signed-off-by: Joshua M. Boniface <joshua@boniface.me>

1 files changed, 688 insertions, 0 deletions

diff --git a/Emby.Server.Implementations/Plugins/PluginManager.cs b/Emby.Server.Implementations/Plugins/PluginManager.cs
new file mode 100644
index 000000000..1ab01252d
--- /dev/null
+++ b/Emby.Server.Implementations/Plugins/PluginManager.cs
@@ -0,0 +1,688 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Text.Json;
+using System.Threading.Tasks;
+using MediaBrowser.Common;
+using MediaBrowser.Common.Extensions;
+using MediaBrowser.Common.Json;
+using MediaBrowser.Common.Json.Converters;
+using MediaBrowser.Common.Plugins;
+using MediaBrowser.Model.Configuration;
+using MediaBrowser.Model.Plugins;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace Emby.Server.Implementations.Plugins
+{
+    /// <summary>
+    /// Defines the <see cref="PluginManager" />.
+    /// </summary>
+    public class PluginManager : IPluginManager
+    {
+        private readonly string _pluginsPath;
+        private readonly Version _appVersion;
+        private readonly JsonSerializerOptions _jsonOptions;
+        private readonly ILogger<PluginManager> _logger;
+        private readonly IApplicationHost _appHost;
+        private readonly ServerConfiguration _config;
+        private readonly IList<LocalPlugin> _plugins;
+        private readonly Version _minimumVersion;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PluginManager"/> class.
+        /// </summary>
+        /// <param name="logger">The <see cref="ILogger"/>.</param>
+        /// <param name="appHost">The <see cref="IApplicationHost"/>.</param>
+        /// <param name="config">The <see cref="ServerConfiguration"/>.</param>
+        /// <param name="pluginsPath">The plugin path.</param>
+        /// <param name="appVersion">The application version.</param>
+        public PluginManager(
+            ILogger<PluginManager> logger,
+            IApplicationHost appHost,
+            ServerConfiguration config,
+            string pluginsPath,
+            Version appVersion)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _pluginsPath = pluginsPath;
+            _appVersion = appVersion ?? throw new ArgumentNullException(nameof(appVersion));
+            _jsonOptions = new JsonSerializerOptions(JsonDefaults.GetOptions())
+            {
+                WriteIndented = true
+            };
+
+            // We need to use the default GUID converter, so we need to remove any custom ones.
+            for (int a = _jsonOptions.Converters.Count - 1; a >= 0; a--)
+            {
+                if (_jsonOptions.Converters[a] is JsonGuidConverter convertor)
+                {
+                    _jsonOptions.Converters.Remove(convertor);
+                    break;
+                }
+            }
+
+            _config = config;
+            _appHost = appHost;
+            _minimumVersion = new Version(0, 0, 0, 1);
+            _plugins = Directory.Exists(_pluginsPath) ? DiscoverPlugins().ToList() : new List<LocalPlugin>();
+        }
+
+        /// <summary>
+        /// Gets the Plugins.
+        /// </summary>
+        public IList<LocalPlugin> Plugins => _plugins;
+
+        /// <summary>
+        /// Returns all the assemblies.
+        /// </summary>
+        /// <returns>An IEnumerable{Assembly}.</returns>
+        public IEnumerable<Assembly> LoadAssemblies()
+        {
+            // Attempt to remove any deleted plugins and change any successors to be active.
+            for (int i = _plugins.Count - 1; i >= 0; i--)
+            {
+                var plugin = _plugins[i];
+                if (plugin.Manifest.Status == PluginStatus.Deleted && DeletePlugin(plugin))
+                {
+                    // See if there is another version, and if so make that active.
+                    ProcessAlternative(plugin);
+                }
+            }
+
+            // Now load the assemblies..
+            foreach (var plugin in _plugins)
+            {
+                UpdatePluginSuperceedStatus(plugin);
+
+                if (plugin.IsEnabledAndSupported == false)
+                {
+                    _logger.LogInformation("Skipping disabled plugin {Version} of {Name} ", plugin.Version, plugin.Name);
+                    continue;
+                }
+
+                foreach (var file in plugin.DllFiles)
+                {
+                    Assembly assembly;
+                    try
+                    {
+                        assembly = Assembly.LoadFrom(file);
+
+                        // This force loads all reference dll's that the plugin uses in the try..catch block.
+                        // Removing this will cause JF to bomb out if referenced dll's cause issues.
+                        assembly.GetExportedTypes();
+                    }
+                    catch (FileLoadException ex)
+                    {
+                        _logger.LogError(ex, "Failed to load assembly {Path}. Disabling plugin.", file);
+                        ChangePluginState(plugin, PluginStatus.Malfunctioned);
+                        continue;
+                    }
+
+                    _logger.LogInformation("Loaded assembly {Assembly} from {Path}", assembly.FullName, file);
+                    yield return assembly;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Creates all the plugin instances.
+        /// </summary>
+        public void CreatePlugins()
+        {
+            _ = _appHost.GetExports<IPlugin>(CreatePluginInstance)
+                .Where(i => i != null)
+                .ToArray();
+        }
+
+        /// <summary>
+        /// Registers the plugin's services with the DI.
+        /// Note: DI is not yet instantiated yet.
+        /// </summary>
+        /// <param name="serviceCollection">A <see cref="ServiceCollection"/> instance.</param>
+        public void RegisterServices(IServiceCollection serviceCollection)
+        {
+            foreach (var pluginServiceRegistrator in _appHost.GetExportTypes<IPluginServiceRegistrator>())
+            {
+                var plugin = GetPluginByAssembly(pluginServiceRegistrator.Assembly);
+                if (plugin == null)
+                {
+                    _logger.LogError("Unable to find plugin in assembly {Assembly}", pluginServiceRegistrator.Assembly.FullName);
+                    continue;
+                }
+
+                UpdatePluginSuperceedStatus(plugin);
+                if (!plugin.IsEnabledAndSupported)
+                {
+                    continue;
+                }
+
+                try
+                {
+                    var instance = (IPluginServiceRegistrator?)Activator.CreateInstance(pluginServiceRegistrator);
+                    instance?.RegisterServices(serviceCollection);
+                }
+#pragma warning disable CA1031 // Do not catch general exception types
+                catch (Exception ex)
+#pragma warning restore CA1031 // Do not catch general exception types
+                {
+                    _logger.LogError(ex, "Error registering plugin services from {Assembly}.", pluginServiceRegistrator.Assembly.FullName);
+                    if (ChangePluginState(plugin, PluginStatus.Malfunctioned))
+                    {
+                        _logger.LogInformation("Disabling plugin {Path}", plugin.Path);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Imports a plugin manifest from <paramref name="folder"/>.
+        /// </summary>
+        /// <param name="folder">Folder of the plugin.</param>
+        public void ImportPluginFrom(string folder)
+        {
+            if (string.IsNullOrEmpty(folder))
+            {
+                throw new ArgumentNullException(nameof(folder));
+            }
+
+            // Load the plugin.
+            var plugin = LoadManifest(folder);
+            // Make sure we haven't already loaded this.
+            if (_plugins.Any(p => p.Manifest.Equals(plugin.Manifest)))
+            {
+                return;
+            }
+
+            _plugins.Add(plugin);
+            EnablePlugin(plugin);
+        }
+
+        /// <summary>
+        /// Removes the plugin reference '<paramref name="plugin"/>.
+        /// </summary>
+        /// <param name="plugin">The plugin.</param>
+        /// <returns>Outcome of the operation.</returns>
+        public bool RemovePlugin(LocalPlugin plugin)
+        {
+            if (plugin == null)
+            {
+                throw new ArgumentNullException(nameof(plugin));
+            }
+
+            if (DeletePlugin(plugin))
+            {
+                ProcessAlternative(plugin);
+                return true;
+            }
+
+            _logger.LogWarning("Unable to delete {Path}, so marking as deleteOnStartup.", plugin.Path);
+            // Unable to delete, so disable.
+            if (ChangePluginState(plugin, PluginStatus.Deleted))
+            {
+                ProcessAlternative(plugin);
+                return true;
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Attempts to find the plugin with and id of <paramref name="id"/>.
+        /// </summary>
+        /// <param name="id">The <see cref="Guid"/> of plugin.</param>
+        /// <param name="version">Optional <see cref="Version"/> of the plugin to locate.</param>
+        /// <returns>A <see cref="LocalPlugin"/> if located, or null if not.</returns>
+        public LocalPlugin? GetPlugin(Guid id, Version? version = null)
+        {
+            LocalPlugin? plugin;
+
+            if (version == null)
+            {
+                // If no version is given, return the current instance.
+                var plugins = _plugins.Where(p => p.Id.Equals(id)).ToList();
+
+                plugin = plugins.FirstOrDefault(p => p.Instance != null);
+                if (plugin == null)
+                {
+                    plugin = plugins.OrderByDescending(p => p.Version).FirstOrDefault();
+                }
+            }
+            else
+            {
+                // Match id and version number.
+                plugin = _plugins.FirstOrDefault(p => p.Id.Equals(id) && p.Version.Equals(version));
+            }
+
+            return plugin;
+        }
+
+        /// <summary>
+        /// Enables the plugin, disabling all other versions.
+        /// </summary>
+        /// <param name="plugin">The <see cref="LocalPlugin"/> of the plug to disable.</param>
+        public void EnablePlugin(LocalPlugin plugin)
+        {
+            if (plugin == null)
+            {
+                throw new ArgumentNullException(nameof(plugin));
+            }
+
+            if (ChangePluginState(plugin, PluginStatus.Active))
+            {
+                // See if there is another version, and if so, supercede it.
+                ProcessAlternative(plugin);
+            }
+        }
+
+        /// <summary>
+        /// Disable the plugin.
+        /// </summary>
+        /// <param name="plugin">The <see cref="LocalPlugin"/> of the plug to disable.</param>
+        public void DisablePlugin(LocalPlugin plugin)
+        {
+            if (plugin == null)
+            {
+                throw new ArgumentNullException(nameof(plugin));
+            }
+
+            // Update the manifest on disk
+            if (ChangePluginState(plugin, PluginStatus.Disabled))
+            {
+                // If there is another version, activate it.
+                ProcessAlternative(plugin);
+            }
+        }
+
+        /// <summary>
+        /// Disable the plugin.
+        /// </summary>
+        /// <param name="assembly">The <see cref="Assembly"/> of the plug to disable.</param>
+        public void FailPlugin(Assembly assembly)
+        {
+            // Only save if disabled.
+            if (assembly == null)
+            {
+                throw new ArgumentNullException(nameof(assembly));
+            }
+
+            var plugin = _plugins.FirstOrDefault(p => p.DllFiles.Contains(assembly.Location));
+            if (plugin == null)
+            {
+                // A plugin's assembly didn't cause this issue, so ignore it.
+                return;
+            }
+
+            ChangePluginState(plugin, PluginStatus.Malfunctioned);
+        }
+
+        /// <summary>
+        /// Saves the manifest back to disk.
+        /// </summary>
+        /// <param name="manifest">The <see cref="PluginManifest"/> to save.</param>
+        /// <param name="path">The path where to save the manifest.</param>
+        /// <returns>True if successful.</returns>
+        public bool SaveManifest(PluginManifest manifest, string path)
+        {
+            if (manifest == null)
+            {
+                return false;
+            }
+
+            try
+            {
+                var data = JsonSerializer.Serialize(manifest, _jsonOptions);
+                File.WriteAllText(Path.Combine(path, "meta.json"), data, Encoding.UTF8);
+                return true;
+            }
+#pragma warning disable CA1031 // Do not catch general exception types
+            catch (Exception e)
+#pragma warning restore CA1031 // Do not catch general exception types
+            {
+                _logger.LogWarning(e, "Unable to save plugin manifest. {Path}", path);
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Changes a plugin's load status.
+        /// </summary>
+        /// <param name="plugin">The <see cref="LocalPlugin"/> instance.</param>
+        /// <param name="state">The <see cref="PluginStatus"/> of the plugin.</param>
+        /// <returns>Success of the task.</returns>
+        private bool ChangePluginState(LocalPlugin plugin, PluginStatus state)
+        {
+            if (plugin.Manifest.Status == state || string.IsNullOrEmpty(plugin.Path))
+            {
+                // No need to save as the state hasn't changed.
+                return true;
+            }
+
+            plugin.Manifest.Status = state;
+            return SaveManifest(plugin.Manifest, plugin.Path);
+        }
+
+        /// <summary>
+        /// Finds the plugin record using the assembly.
+        /// </summary>
+        /// <param name="assembly">The <see cref="Assembly"/> being sought.</param>
+        /// <returns>The matching record, or null if not found.</returns>
+        private LocalPlugin? GetPluginByAssembly(Assembly assembly)
+        {
+            // Find which plugin it is by the path.
+            return _plugins.FirstOrDefault(p => string.Equals(p.Path, Path.GetDirectoryName(assembly.Location), StringComparison.Ordinal));
+        }
+
+        /// <summary>
+        /// Creates the instance safe.
+        /// </summary>
+        /// <param name="type">The type.</param>
+        /// <returns>System.Object.</returns>
+        private IPlugin? CreatePluginInstance(Type type)
+        {
+            // Find the record for this plugin.
+            var plugin = GetPluginByAssembly(type.Assembly);
+            if (plugin?.Manifest.Status < PluginStatus.Active)
+            {
+                return null;
+            }
+
+            try
+            {
+                _logger.LogDebug("Creating instance of {Type}", type);
+                var instance = (IPlugin)ActivatorUtilities.CreateInstance(_appHost.ServiceProvider, type);
+                if (plugin == null)
+                {
+                    // Create a dummy record for the providers.
+                    // TODO: remove this code, if all provided have been released as separate plugins.
+                    plugin = new LocalPlugin(
+                        instance.AssemblyFilePath,
+                        true,
+                        new PluginManifest
+                        {
+                            Id = instance.Id,
+                            Status = PluginStatus.Active,
+                            Name = instance.Name,
+                            Version = instance.Version.ToString()
+                        })
+                    {
+                        Instance = instance
+                    };
+
+                    _plugins.Add(plugin);
+
+                    plugin.Manifest.Status = PluginStatus.Active;
+                }
+                else
+                {
+                    plugin.Instance = instance;
+                    var manifest = plugin.Manifest;
+                    var pluginStr = plugin.Instance.Version.ToString();
+                    bool changed = false;
+                    if (string.Equals(manifest.Version, pluginStr, StringComparison.Ordinal))
+                    {
+                        // If a plugin without a manifest failed to load due to an external issue (eg config),
+                        // this updates the manifest to the actual plugin values.
+                        manifest.Version = pluginStr;
+                        manifest.Name = plugin.Instance.Name;
+                        manifest.Description = plugin.Instance.Description;
+                        changed = true;
+                    }
+
+                    changed = changed || manifest.Status != PluginStatus.Active;
+                    manifest.Status = PluginStatus.Active;
+
+                    if (changed)
+                    {
+                        SaveManifest(manifest, plugin.Path);
+                    }
+                }
+
+                _logger.LogInformation("Loaded plugin: {PluginName} {PluginVersion}", plugin.Name, plugin.Version);
+
+                return instance;
+            }
+#pragma warning disable CA1031 // Do not catch general exception types
+            catch (Exception ex)
+#pragma warning restore CA1031 // Do not catch general exception types
+            {
+                _logger.LogError(ex, "Error creating {Type}", type.FullName);
+                if (plugin != null)
+                {
+                    if (ChangePluginState(plugin, PluginStatus.Malfunctioned))
+                    {
+                        _logger.LogInformation("Plugin {Path} has been disabled.", plugin.Path);
+                        return null;
+                    }
+                }
+
+                _logger.LogDebug("Unable to auto-disable.");
+                return null;
+            }
+        }
+
+        private void UpdatePluginSuperceedStatus(LocalPlugin plugin)
+        {
+            if (plugin.Manifest.Status != PluginStatus.Superceded)
+            {
+                return;
+            }
+
+            var predecessor = _plugins.OrderByDescending(p => p.Version)
+                .FirstOrDefault(p => p.Id.Equals(plugin.Id) && p.IsEnabledAndSupported && p.Version != plugin.Version);
+            if (predecessor != null)
+            {
+                return;
+            }
+
+            plugin.Manifest.Status = PluginStatus.Active;
+        }
+
+        /// <summary>
+        /// Attempts to delete a plugin.
+        /// </summary>
+        /// <param name="plugin">A <see cref="LocalPlugin"/> instance to delete.</param>
+        /// <returns>True if successful.</returns>
+        private bool DeletePlugin(LocalPlugin plugin)
+        {
+            // Attempt a cleanup of old folders.
+            try
+            {
+                Directory.Delete(plugin.Path, true);
+                _logger.LogDebug("Deleted {Path}", plugin.Path);
+            }
+#pragma warning disable CA1031 // Do not catch general exception types
+            catch
+#pragma warning restore CA1031 // Do not catch general exception types
+            {
+                return false;
+            }
+
+            return _plugins.Remove(plugin);
+        }
+
+        private LocalPlugin LoadManifest(string dir)
+        {
+            Version? version;
+            PluginManifest? manifest = null;
+            var metafile = Path.Combine(dir, "meta.json");
+            if (File.Exists(metafile))
+            {
+                try
+                {
+                    var data = File.ReadAllText(metafile, Encoding.UTF8);
+                    manifest = JsonSerializer.Deserialize<PluginManifest>(data, _jsonOptions);
+                }
+#pragma warning disable CA1031 // Do not catch general exception types
+                catch (Exception ex)
+#pragma warning restore CA1031 // Do not catch general exception types
+                {
+                    _logger.LogError(ex, "Error deserializing {Path}.", dir);
+                }
+            }
+
+            if (manifest != null)
+            {
+                if (!Version.TryParse(manifest.TargetAbi, out var targetAbi))
+                {
+                    targetAbi = _minimumVersion;
+                }
+
+                if (!Version.TryParse(manifest.Version, out version))
+                {
+                    manifest.Version = _minimumVersion.ToString();
+                }
+
+                return new LocalPlugin(dir, _appVersion >= targetAbi, manifest);
+            }
+
+            // No metafile, so lets see if the folder is versioned.
+            // TODO: Phase this support out in future versions.
+            metafile = dir.Split(Path.DirectorySeparatorChar, StringSplitOptions.RemoveEmptyEntries)[^1];
+            int versionIndex = dir.LastIndexOf('_');
+            if (versionIndex != -1)
+            {
+                // Get the version number from the filename if possible.
+                metafile = Path.GetFileName(dir[..versionIndex]) ?? dir[..versionIndex];
+                version = Version.TryParse(dir.AsSpan()[(versionIndex + 1)..], out Version? parsedVersion) ? parsedVersion : _appVersion;
+            }
+            else
+            {
+                // Un-versioned folder - Add it under the path name and version it suitable for this instance.
+                version = _appVersion;
+            }
+
+            // Auto-create a plugin manifest, so we can disable it, if it fails to load.
+            manifest = new PluginManifest
+            {
+                Status = PluginStatus.Restart,
+                Name = metafile,
+                AutoUpdate = false,
+                Id = metafile.GetMD5(),
+                TargetAbi = _appVersion.ToString(),
+                Version = version.ToString()
+            };
+
+            return new LocalPlugin(dir, true, manifest);
+        }
+
+        /// <summary>
+        /// Gets the list of local plugins.
+        /// </summary>
+        /// <returns>Enumerable of local plugins.</returns>
+        private IEnumerable<LocalPlugin> DiscoverPlugins()
+        {
+            var versions = new List<LocalPlugin>();
+
+            if (!Directory.Exists(_pluginsPath))
+            {
+                // Plugin path doesn't exist, don't try to enumerate sub-folders.
+                return Enumerable.Empty<LocalPlugin>();
+            }
+
+            var directories = Directory.EnumerateDirectories(_pluginsPath, "*.*", SearchOption.TopDirectoryOnly);
+            foreach (var dir in directories)
+            {
+                versions.Add(LoadManifest(dir));
+            }
+
+            string lastName = string.Empty;
+            versions.Sort(LocalPlugin.Compare);
+            // Traverse backwards through the list.
+            // The first item will be the latest version.
+            for (int x = versions.Count - 1; x >= 0; x--)
+            {
+                var entry = versions[x];
+                if (!string.Equals(lastName, entry.Name, StringComparison.OrdinalIgnoreCase))
+                {
+                    entry.DllFiles.AddRange(Directory.EnumerateFiles(entry.Path, "*.dll", SearchOption.AllDirectories));
+                    if (entry.IsEnabledAndSupported)
+                    {
+                        lastName = entry.Name;
+                        continue;
+                    }
+                }
+
+                if (string.IsNullOrEmpty(lastName))
+                {
+                    continue;
+                }
+
+                var manifest = entry.Manifest;
+                var cleaned = false;
+                var path = entry.Path;
+                if (_config.RemoveOldPlugins)
+                {
+                    // Attempt a cleanup of old folders.
+                    try
+                    {
+                        _logger.LogDebug("Deleting {Path}", path);
+                        Directory.Delete(path, true);
+                        cleaned = true;
+                    }
+#pragma warning disable CA1031 // Do not catch general exception types
+                    catch (Exception e)
+#pragma warning restore CA1031 // Do not catch general exception types
+                    {
+                        _logger.LogWarning(e, "Unable to delete {Path}", path);
+                    }
+
+                    if (cleaned)
+                    {
+                        versions.RemoveAt(x);
+                    }
+                    else
+                    {
+                        if (manifest == null)
+                        {
+                            _logger.LogWarning("Unable to disable plugin {Path}", entry.Path);
+                            continue;
+                        }
+
+                        ChangePluginState(entry, PluginStatus.Deleted);
+                    }
+                }
+            }
+
+            // Only want plugin folders which have files.
+            return versions.Where(p => p.DllFiles.Count != 0);
+        }
+
+        /// <summary>
+        /// Changes the status of the other versions of the plugin to "Superceded".
+        /// </summary>
+        /// <param name="plugin">The <see cref="LocalPlugin"/> that's master.</param>
+        private void ProcessAlternative(LocalPlugin plugin)
+        {
+            // Detect whether there is another version of this plugin that needs disabling.
+            var previousVersion = _plugins.OrderByDescending(p => p.Version)
+                .FirstOrDefault(
+                    p => p.Id.Equals(plugin.Id)
+                    && p.IsEnabledAndSupported
+                    && p.Version != plugin.Version);
+
+            if (previousVersion == null)
+            {
+                // This value is memory only - so that the web will show restart required.
+                plugin.Manifest.Status = PluginStatus.Restart;
+                return;
+            }
+
+            if (plugin.Manifest.Status == PluginStatus.Active && !ChangePluginState(previousVersion, PluginStatus.Superceded))
+            {
+                _logger.LogError("Unable to enable version {Version} of {Name}", previousVersion.Version, previousVersion.Name);
+            }
+            else if (plugin.Manifest.Status == PluginStatus.Superceded && !ChangePluginState(previousVersion, PluginStatus.Active))
+            {
+                _logger.LogError("Unable to supercede version {Version} of {Name}", previousVersion.Version, previousVersion.Name);
+            }
+
+            // This value is memory only - so that the web will show restart required.
+            plugin.Manifest.Status = PluginStatus.Restart;
+        }
+    }
+}