Remove OnPrepareDetectionAsync method from the DockerfileComponentDetector

src/Microsoft.ComponentDetection.Detectors/dockerfile/DockerfileComponentDetector.cs

@@ -4,7 +4,6 @@ namespace Microsoft.ComponentDetection.Detectors.Dockerfile;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Reactive.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.ComponentDetection.Common;
@@ -46,18 +45,18 @@ public DockerfileComponentDetector(
 
     protected override IList<string> SkippedFolders => ["node_modules"];
 
-    protected override Task<IObservable<ProcessRequest>> OnPrepareDetectionAsync(
-        IObservable<ProcessRequest> processRequests,
-        IDictionary<string, string> detectorArgs,
-        CancellationToken cancellationToken = default) =>
-        Task.FromResult(processRequests.Where(processRequest =>
-            !this.IsInSkippedFolder(processRequest.ComponentStream.Location)));
-
     protected override async Task OnFileFoundAsync(ProcessRequest processRequest, IDictionary<string, string> detectorArgs, CancellationToken cancellationToken = default)
     {
         var singleFileComponentRecorder = processRequest.SingleFileComponentRecorder;
         var file = processRequest.ComponentStream;
         var filePath = file.Location;
+        var skippedFolder = this.SkippedFolders.FirstOrDefault(folder => filePath.Contains(folder));
+        if (!string.IsNullOrEmpty(skippedFolder))
+        {
+            this.Logger.LogDebug("Ignoring Dockerfile at {DockerfileLocation}, as it is inside a {SkippedFolder} folder.", filePath, skippedFolder);
+            return;
+        }
+
         try
         {
             this.Logger.LogInformation("Discovered dockerfile: {Location}", file.Location);
@@ -73,20 +72,14 @@ protected override async Task OnFileFoundAsync(ProcessRequest processRequest, ID
         }
         catch (ParseException e)
         {
-            this.Logger.LogWarning(e, "Ignoring file that doesn't appear to be a Dockerfile: {Location}", filePath);
+            this.Logger.LogDebug(e, "Ignoring file that doesn't appear to be a Dockerfile: {Location}", filePath);
         }
         catch (Exception e)
         {
             this.Logger.LogError(e, "Failed to process Dockerfile: {Location}", filePath);
         }
     }
 
-    private bool IsInSkippedFolder(string filePath)
-    {
-        var pathSegments = filePath.Split(['/', '\\'], StringSplitOptions.RemoveEmptyEntries);
-        return this.SkippedFolders.Any(skippedFolder => pathSegments.Contains(skippedFolder, StringComparer.OrdinalIgnoreCase));
-    }
-
     private Task ParseDockerFileAsync(string fileContents, string fileLocation, ISingleFileComponentRecorder singleFileComponentRecorder, Dictionary<string, string> stageNameMap)
     {
         var dockerfileModel = Dockerfile.Parse(fileContents);

test/Microsoft.ComponentDetection.Detectors.Tests/DockerfileComponentDetectorTests.cs

@@ -229,12 +229,20 @@ public async Task TestDockerfile_ShikiLanguageDefinitionIsIgnoredAsync(string fi
         componentRecorder.GetDetectedComponents().Should().BeEmpty();
         loggerMock.Verify(
             logger => logger.Log(
-                LogLevel.Warning,
+                LogLevel.Debug,
                 It.IsAny<EventId>(),
                 It.IsAny<It.IsAnyType>(),
                 It.IsAny<Exception>(),
                 It.IsAny<Func<It.IsAnyType, Exception?, string>>()),
             Times.Once);
+        loggerMock.Verify(
+            logger => logger.Log(
+                LogLevel.Warning,
+                It.IsAny<EventId>(),
+                It.IsAny<It.IsAnyType>(),
+                It.IsAny<Exception>(),
+                It.IsAny<Func<It.IsAnyType, Exception?, string>>()),
+            Times.Never);
         loggerMock.Verify(
             logger => logger.Log(
                 LogLevel.Error,