/// <summary>
/// Asynchronously discovers plugins.
/// </summary>
/// <param name="cancellationToken">A cancellation token.</param>
/// <returns>A task that represents the asynchronous operation.
/// The task result (<see cref="Task{TResult}.Result" />) returns a
/// <see cref="IEnumerable{PluginDiscoveryResult}" /> from the target.</returns>
/// <exception cref="OperationCanceledException">Thrown if <paramref name="cancellationToken" />
/// is cancelled.</exception>
public async Task <IEnumerable <PluginDiscoveryResult> > DiscoverAsync(CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
if (_results != null)
{
return(_results);
}
await _semaphore.WaitAsync(cancellationToken).ConfigureAwait(false);
try
{
if (_results != null)
{
return(_results);
}
_pluginFiles = GetPluginFiles(cancellationToken);
var results = new List <PluginDiscoveryResult>();
for (var i = 0; i < _pluginFiles.Count; ++i)
{
var pluginFile = _pluginFiles[i];
var result = new PluginDiscoveryResult(pluginFile);
results.Add(result);
}
_results = results;
}
finally
{
_semaphore.Release();
}
return(_results);
}
/// <summary>
/// Creates a plugin from the discovered plugin.
/// We firstly check the cache for the operation claims for the given request key.
/// If there is a valid cache entry, and it does contain the requested operation claim, then we start the plugin, and if need be update the cache value itself.
/// If there is a valid cache entry, and it does NOT contain the requested operation claim, then we return a null.
/// If there is no valid cache entry or an invalid one, we start the plugin as normally, return an active plugin even if the requested claim is not available, and write a cache entry.
/// </summary>
/// <param name="result">plugin discovery result</param>
/// <param name="requestedOperationClaim">The requested operation claim</param>
/// <param name="requestKey">plugin request key</param>
/// <param name="packageSourceRepository">package source repository</param>
/// <param name="serviceIndex">service index</param>
/// <param name="cancellationToken">cancellation token</param>
/// <returns>A plugin creation result, null if the requested plugin cannot handle the given operation claim</returns>
private async Task <Tuple <bool, PluginCreationResult> > TryCreatePluginAsync(
PluginDiscoveryResult result,
OperationClaim requestedOperationClaim,
PluginRequestKey requestKey,
string packageSourceRepository,
JObject serviceIndex,
CancellationToken cancellationToken)
{
PluginCreationResult pluginCreationResult = null;
var cacheEntry = new PluginCacheEntry(_pluginsCacheDirectoryPath.Value, result.PluginFile.Path, requestKey.PackageSourceRepository);
ConcurrencyUtilities.ExecuteWithFileLocked(cacheEntry.CacheFileName, cacheEntry.LoadFromFile);
if (cacheEntry.OperationClaims == null || cacheEntry.OperationClaims.Contains(requestedOperationClaim))
{
try
{
if (result.PluginFile.State.Value == PluginFileState.Valid)
{
var plugin = await _pluginFactory.GetOrCreateAsync(
result.PluginFile.Path,
PluginConstants.PluginArguments,
new RequestHandlers(),
_connectionOptions,
cancellationToken);
var utilities = await PerformOneTimePluginInitializationAsync(plugin, cancellationToken);
// We still make the GetOperationClaims call even if we have the operation claims cached. This is a way to self-update the cache.
var operationClaims = await _pluginOperationClaims.GetOrAdd(
requestKey,
key => new Lazy <Task <IReadOnlyList <OperationClaim> > >(() =>
GetPluginOperationClaimsAsync(
plugin,
packageSourceRepository,
serviceIndex,
cancellationToken))).Value;
if (!EqualityUtility.SequenceEqualWithNullCheck(operationClaims, cacheEntry.OperationClaims))
{
cacheEntry.OperationClaims = operationClaims;
await utilities.Value.DoOncePerPluginLifetimeAsync(
nameof(PluginCacheEntry),
() => ConcurrencyUtilities.ExecuteWithFileLockedAsync(
cacheEntry.CacheFileName,
action: async lockedToken =>
{
await cacheEntry.UpdateCacheFileAsync();
return(Task.FromResult <object>(null));
},
token: cancellationToken),
cancellationToken);
}
pluginCreationResult = new PluginCreationResult(
plugin,
utilities.Value,
operationClaims);
}
else
{
pluginCreationResult = new PluginCreationResult(result.Message);
}
}
catch (Exception e)
{
pluginCreationResult = new PluginCreationResult(
string.Format(CultureInfo.CurrentCulture,
Strings.Plugin_ProblemStartingPlugin,
result.PluginFile.Path,
e.Message),
e);
}
}
return(new Tuple <bool, PluginCreationResult>(pluginCreationResult != null, pluginCreationResult));
}
/// <summary>
/// Creates a plugin from the given pluginDiscoveryResult.
/// This plugin's operations will be source agnostic ones (Authentication)
/// </summary>
/// <param name="pluginDiscoveryResult">plugin discovery result</param>
/// <param name="requestedOperationClaim">The requested operation claim</param>
/// <param name="cancellationToken">cancellation token</param>
/// <returns>A plugin creation result, null if the requested plugin cannot handle the given operation claim</returns>
public Task <Tuple <bool, PluginCreationResult> > TryGetSourceAgnosticPluginAsync(PluginDiscoveryResult pluginDiscoveryResult, OperationClaim requestedOperationClaim, CancellationToken cancellationToken)
{
if (pluginDiscoveryResult == null)
{
throw new ArgumentNullException(nameof(pluginDiscoveryResult));
}
return(TryCreatePluginAsync(
pluginDiscoveryResult,
requestedOperationClaim,
new PluginRequestKey(pluginDiscoveryResult.PluginFile.Path, "Source-Agnostic"),
packageSourceRepository: null,
serviceIndex: null,
cancellationToken: cancellationToken));
}
/// <summary>
/// Asynchronously discovers plugins.
/// </summary>
/// <param name="cancellationToken">A cancellation token.</param>
/// <returns>A task that represents the asynchronous operation.
/// The task result (<see cref="Task{TResult}.Result" />) returns a
/// <see cref="IEnumerable{PluginDiscoveryResult}" /> from the target.</returns>
/// <exception cref="OperationCanceledException">Thrown if <paramref name="cancellationToken" />
/// is cancelled.</exception>
public async Task <IEnumerable <PluginDiscoveryResult> > DiscoverAsync(CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
if (_results != null)
{
return(_results);
}
await _semaphore.WaitAsync(cancellationToken);
try
{
if (_results != null)
{
return(_results);
}
_pluginFiles = GetPluginFiles(cancellationToken);
var results = new List <PluginDiscoveryResult>();
for (var i = 0; i < _pluginFiles.Count; ++i)
{
var pluginFile = _pluginFiles[i];
string message = null;
switch (pluginFile.State)
{
case PluginFileState.Valid:
break;
case PluginFileState.NotFound:
message = string.Format(
CultureInfo.CurrentCulture,
Strings.Plugin_FileNotFound,
pluginFile.Path);
break;
case PluginFileState.InvalidFilePath:
message = string.Format(
CultureInfo.CurrentCulture,
Strings.Plugin_InvalidPluginFilePath,
pluginFile.Path);
break;
case PluginFileState.InvalidEmbeddedSignature:
message = string.Format(
CultureInfo.CurrentCulture,
Strings.Plugin_InvalidEmbeddedSignature,
pluginFile.Path);
break;
default:
throw new NotImplementedException();
}
var result = new PluginDiscoveryResult(pluginFile, message);
results.Add(result);
}
_results = results;
}
finally
{
_semaphore.Release();
}
return(_results);
}
