[release-4.7] Bug 2034506: Make config parsing more resilient for unknown fields

go-controller/pkg/config/config.go

@@ -1316,7 +1316,11 @@ func initConfigWithPath(ctx *cli.Context, exec kexec.Interface, saPath string, d
 
 		// Parse ovn-k8s config file.
 		if err = gcfg.ReadInto(&cfg, f); err != nil {
-			return "", fmt.Errorf("failed to parse config file %s: %v", f.Name(), err)
+			if gcfg.FatalOnly(err) != nil {
+				return "", fmt.Errorf("failed to parse config file %s: %v", f.Name(), err)
+			}
+			// error is only a warning -> log it but continue
+			klog.Warningf("Warning on parsing config file: %s", err)
 		}
 		klog.Infof("Parsed config file %s", f.Name())
 		klog.Infof("Parsed config: %+v", cfg)

go-controller/pkg/config/config_test.go

@@ -1107,6 +1107,59 @@ mode=shared
 		gomega.Expect(err).NotTo(gomega.HaveOccurred())
 	})
 
+	It("ignores unknown fields in config file and does not return an error", func() {
+		err := ioutil.WriteFile(cfgFile.Name(), []byte(`[default]
+key=value
+mtu=1234
+
+[foobar]
+foo=bar
+`), 0644)
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+
+		app.Action = func(ctx *cli.Context) error {
+			var cfgPath string
+			cfgPath, err = InitConfig(ctx, kexec.New(), nil)
+
+			// unknown section foobar and its keys & values should be ignored
+			// same for key=value in default section
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+
+			gomega.Expect(cfgPath).To(gomega.Equal(cfgFile.Name()))
+			gomega.Expect(Default.MTU).To(gomega.Equal(1234))
+			return nil
+		}
+		cliArgs := []string{
+			app.Name,
+			"-config-file=" + cfgFile.Name(),
+		}
+		err = app.Run(cliArgs)
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+	})
+
+	It("rejects a config with invalid syntax", func() {
+		err := ioutil.WriteFile(cfgFile.Name(), []byte(`[default]
+mtu=1234
+
+[foobar
+foo=bar
+`), 0644)
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+
+		app.Action = func(ctx *cli.Context) error {
+			_, err = InitConfig(ctx, kexec.New(), nil)
+			gomega.Expect(err).To(gomega.HaveOccurred())
+
+			return nil
+		}
+		cliArgs := []string{
+			app.Name,
+			"-config-file=" + cfgFile.Name(),
+		}
+		err = app.Run(cliArgs)
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+	})
+
 	Describe("OvnDBAuth operations", func() {
 		var certFile, keyFile, caFile string