cni: handle multi-path cni_path when fingerprinting plugins (#16163)

This PR fixes the CNI plugin fingerprinter to take into account the fact
that the cni_path config can be a multi-path (e.g. `/foo:/bar:/baz`).

Accumulate plugins from each of the possible path elements. If scanning
any of the named directory fails, the fingerprinter fails.

Fixes #16083

No CL/BP - has not shipped yet.

client/fingerprint/plugins_cni.go

@@ -40,24 +40,28 @@ func (f *PluginsCNIFingerprint) Fingerprint(req *FingerprintRequest, resp *Finge
 		return nil
 	}
 
-	// list the cni_path directory
-	entries, err := f.lister(cniPath)
-	switch {
-	case err != nil:
-		f.logger.Warn("failed to read CNI plugins directory", "cni_path", cniPath, "error", err)
-		resp.Detected = false
-		return nil
-	case len(entries) == 0:
-		f.logger.Debug("no CNI plugins found", "cni_path", cniPath)
-		resp.Detected = true
-		return nil
-	}
+	// cniPath could be a multi-path, e.g. /opt/cni/bin:/custom/cni/bin
+	cniPathList := filepath.SplitList(cniPath)
+	for _, cniPath = range cniPathList {
+		// list the cni_path directory
+		entries, err := f.lister(cniPath)
+		switch {
+		case err != nil:
+			f.logger.Warn("failed to read CNI plugins directory", "cni_path", cniPath, "error", err)
+			resp.Detected = false
+			return nil
+		case len(entries) == 0:
+			f.logger.Debug("no CNI plugins found", "cni_path", cniPath)
+			resp.Detected = true
+			return nil
+		}
 
-	// for each file in cni_path, detect executables and try to get their version
-	for _, entry := range entries {
-		v, ok := f.detectOne(cniPath, entry)
-		if ok {
-			resp.AddAttribute(f.attribute(entry.Name()), v)
+		// for each file in cni_path, detect executables and try to get their version
+		for _, entry := range entries {
+			v, ok := f.detectOnePlugin(cniPath, entry)
+			if ok {
+				resp.AddAttribute(f.attribute(entry.Name()), v)
+			}
 		}
 	}
 
@@ -70,7 +74,7 @@ func (f *PluginsCNIFingerprint) attribute(filename string) string {
 	return fmt.Sprintf("%s.%s", cniPluginAttribute, filename)
 }
 
-func (f *PluginsCNIFingerprint) detectOne(cniPath string, entry os.DirEntry) (string, bool) {
+func (f *PluginsCNIFingerprint) detectOnePlugin(pluginPath string, entry os.DirEntry) (string, bool) {
 	fi, err := entry.Info()
 	if err != nil {
 		f.logger.Debug("failed to read cni directory entry", "error", err)
@@ -82,7 +86,7 @@ func (f *PluginsCNIFingerprint) detectOne(cniPath string, entry os.DirEntry) (st
 		return "", false // not executable
 	}
 
-	exePath := filepath.Join(cniPath, fi.Name())
+	exePath := filepath.Join(pluginPath, fi.Name())
 	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
 	defer cancel()
 

client/fingerprint/plugins_cni_test.go

@@ -30,6 +30,28 @@ func TestPluginsCNIFingerprint_Fingerprint_present(t *testing.T) {
 	must.Eq(t, "v1.0.2", response.Attributes[attrBridge])
 }
 
+func TestPluginsCNIFingerprint_Fingerprint_multi(t *testing.T) {
+	ci.Parallel(t)
+
+	f := NewPluginsCNIFingerprint(testlog.HCLogger(t))
+	request := &FingerprintRequest{
+		Config: &config.Config{
+			CNIPath: "./test_fixtures/cni:./test_fixtures/cni2",
+		},
+	}
+	response := new(FingerprintResponse)
+
+	err := f.Fingerprint(request, response)
+	must.NoError(t, err)
+	must.True(t, response.Detected)
+	attrCustom := f.(*PluginsCNIFingerprint).attribute("custom")
+	attrBridge := f.(*PluginsCNIFingerprint).attribute("bridge")
+	attrCustom2 := f.(*PluginsCNIFingerprint).attribute("custom2")
+	must.Eq(t, "v1.2.3", response.Attributes[attrCustom])
+	must.Eq(t, "v1.0.2", response.Attributes[attrBridge])
+	must.Eq(t, "v9.9.9", response.Attributes[attrCustom2])
+}
+
 func TestPluginsCNIFingerprint_Fingerprint_absent(t *testing.T) {
 	ci.Parallel(t)
 

client/fingerprint/test_fixtures/cni2/custom2

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+echo "Custom v9.9.9 Plugin"