Merge pull request #1178 from bergmeister/Performance_RunspacePool_AndSpeedupAvoidAlias

Speedup cold runs of PSSA by using a runspace pool and parallelizing the slowest rule (AvoidAlias)

Author: JamesWTruher

Engine/CommandInfoCache.cs

@@ -5,6 +5,7 @@
 using System.Collections.Concurrent;
 using System.Management.Automation;
 using System.Linq;
+using System.Management.Automation.Runspaces;
 
 namespace Microsoft.Windows.PowerShell.ScriptAnalyzer
 {
@@ -14,16 +15,17 @@ namespace Microsoft.Windows.PowerShell.ScriptAnalyzer
     internal class CommandInfoCache
     {
         private readonly ConcurrentDictionary<CommandLookupKey, Lazy<CommandInfo>> _commandInfoCache;
-
         private readonly Helper _helperInstance;
+        private readonly RunspacePool _runspacePool;
 
         /// <summary>
         /// Create a fresh command info cache instance.
         /// </summary>
-        public CommandInfoCache(Helper pssaHelperInstance)
+        public CommandInfoCache(Helper pssaHelperInstance, RunspacePool runspacePool)
         {
             _commandInfoCache = new ConcurrentDictionary<CommandLookupKey, Lazy<CommandInfo>>();
             _helperInstance = pssaHelperInstance;
+            _runspacePool = runspacePool;
         }
 
         /// <summary>
@@ -64,14 +66,16 @@ public CommandInfo GetCommandInfoLegacy(string commandOrAliasName, CommandTypes?
         /// Get a CommandInfo object of the given command name
         /// </summary>
         /// <returns>Returns null if command does not exists</returns>
-        private static CommandInfo GetCommandInfoInternal(string cmdName, CommandTypes? commandType)
+        private CommandInfo GetCommandInfoInternal(string cmdName, CommandTypes? commandType)
         {
             // 'Get-Command ?' would return % for example due to PowerShell interpreting is a single-character-wildcard search and not just the ? alias.
             // For more details see https://github.com/PowerShell/PowerShell/issues/9308
             cmdName = WildcardPattern.Escape(cmdName);
 
             using (var ps = System.Management.Automation.PowerShell.Create())
             {
+                ps.RunspacePool = _runspacePool;
+
                 ps.AddCommand("Get-Command")
                     .AddParameter("Name", cmdName)
                     .AddParameter("ErrorAction", "SilentlyContinue");

Engine/Helper.cs

@@ -11,6 +11,7 @@
 using System.Linq;
 using System.Management.Automation;
 using System.Management.Automation.Language;
+using System.Management.Automation.Runspaces;
 
 namespace Microsoft.Windows.PowerShell.ScriptAnalyzer
 {
@@ -29,6 +30,7 @@ public class Helper
         private PSVersionTable psVersionTable;
 
         private readonly Lazy<CommandInfoCache> _commandInfoCacheLazy;
+        private readonly RunspacePool _runSpacePool;
 
         #endregion
 
@@ -113,7 +115,11 @@ internal set
         /// </summary>
         private Helper()
         {
-            _commandInfoCacheLazy = new Lazy<CommandInfoCache>(() => new CommandInfoCache(pssaHelperInstance: this));
+            // There are 5 rules that use the CommandInfo cache but one rule (AvoidAlias) makes parallel queries.
+            // Therefore 10 runspaces was a heuristic measure where no more speed improvement was seen.
+            _runSpacePool = RunspaceFactory.CreateRunspacePool(1, 10);
+            _runSpacePool.Open();
+            _commandInfoCacheLazy = new Lazy<CommandInfoCache>(() => new CommandInfoCache(pssaHelperInstance: this, runspacePool: _runSpacePool));
         }
 
         /// <summary>
@@ -299,11 +305,12 @@ public PSModuleInfo GetModuleManifest(string filePath, out IEnumerable<ErrorReco
             Collection<PSObject> psObj = null;
             using (var ps = System.Management.Automation.PowerShell.Create())
             {
+                ps.RunspacePool = _runSpacePool;
+                ps.AddCommand("Test-ModuleManifest")
+                  .AddParameter("Path", filePath)
+                  .AddParameter("WarningAction", ActionPreference.SilentlyContinue);
                 try
                 {
-                    ps.AddCommand("Test-ModuleManifest");
-                    ps.AddParameter("Path", filePath);
-                    ps.AddParameter("WarningAction", ActionPreference.SilentlyContinue);
                     psObj = ps.Invoke();
                 }
                 catch (CmdletInvocationException e)