Add validator for proxy log-level (#2256)

Add validator for proxy log-level

Follow-up to #2249

Signed-off-by: Alejandro Pedraza <alejandro@buoyant.io>

cli/cmd/install_test.go

@@ -174,20 +174,54 @@ func TestValidate(t *testing.T) {
 		}
 	})
 
-	t.Run("Rejects invalid log level", func(t *testing.T) {
+	t.Run("Rejects invalid controller log level", func(t *testing.T) {
 		options := newInstallOptions()
 		options.controllerLogLevel = "super"
 		expected := "--controller-log-level must be one of: panic, fatal, error, warn, info, debug"
 
 		err := options.validate()
 		if err == nil {
-			t.Fatalf("Expected error, got nothing")
+			t.Fatal("Expected error, got nothing")
 		}
 		if err.Error() != expected {
 			t.Fatalf("Expected error string\"%s\", got \"%s\"", expected, err)
 		}
 	})
 
+	t.Run("Properly validates proxy log level", func(t *testing.T) {
+		testCases := []struct {
+			input string
+			valid bool
+		}{
+			{"", false},
+			{"info", true},
+			{"somemodule", true},
+			{"bad%name", false},
+			{"linkerd2_proxy=debug", true},
+			{"linkerd2%proxy=debug", false},
+			{"linkerd2_proxy=foobar", false},
+			{"linker2d_proxy,std::option", true},
+			{"warn,linkerd2_proxy=info", true},
+			{"warn,linkerd2_proxy=foobar", false},
+		}
+
+		options := newInstallOptions()
+		for _, tc := range testCases {
+			options.proxyLogLevel = tc.input
+			err := options.validate()
+			if tc.valid && err != nil {
+				t.Fatalf("Error not expected: %s", err)
+			}
+			if !tc.valid && err == nil {
+				t.Fatalf("Expected error string \"%s is not a valid proxy log level\", got nothing", tc.input)
+			}
+			expectedErr := "\"%s\" is not a valid proxy log level - for allowed syntax check https://docs.rs/env_logger/0.6.0/env_logger/#enabling-logging"
+			if !tc.valid && err.Error() != fmt.Sprintf(expectedErr, tc.input) {
+				t.Fatalf("Expected error string \""+expectedErr+"\"", tc.input, err)
+			}
+		}
+	})
+
 	t.Run("Rejects single namespace install with auto inject", func(t *testing.T) {
 		options := newInstallOptions()
 		options.proxyAutoInject = true

cli/cmd/root.go

@@ -42,9 +42,21 @@ var (
 
 	// These regexs are not as strict as they could be, but are a quick and dirty
 	// sanity check against illegal characters.
-	alphaNumDash              = regexp.MustCompile("^[a-zA-Z0-9-]+$")
-	alphaNumDashDot           = regexp.MustCompile("^[\\.a-zA-Z0-9-]+$")
-	alphaNumDashDotSlashColon = regexp.MustCompile("^[\\./a-zA-Z0-9-:]+$")
+	alphaNumDash              = regexp.MustCompile(`^[a-zA-Z0-9-]+$`)
+	alphaNumDashDot           = regexp.MustCompile(`^[\.a-zA-Z0-9-]+$`)
+	alphaNumDashDotSlashColon = regexp.MustCompile(`^[\./a-zA-Z0-9-:]+$`)
+
+	// Full Rust log level syntax at
+	// https://docs.rs/env_logger/0.6.0/env_logger/#enabling-logging
+	r                  = strings.NewReplacer("\t", "", "\n", "")
+	validProxyLogLevel = regexp.MustCompile(r.Replace(`
+		^(
+			(
+				(trace|debug|warn|info|error)|
+				(\w|::)+|
+				((\w|::)+=(trace|debug|warn|info|error))
+			)(?:,|$)
+		)+$`))
 )
 
 // RootCmd represents the root Cobra command
@@ -315,6 +327,11 @@ func (options *proxyConfigOptions) validate() error {
 		return fmt.Errorf("--tls must be blank or set to \"%s\"", optionalTLS)
 	}
 
+	if !validProxyLogLevel.MatchString(options.proxyLogLevel) {
+		return fmt.Errorf("\"%s\" is not a valid proxy log level - for allowed syntax check https://docs.rs/env_logger/0.6.0/env_logger/#enabling-logging",
+			options.proxyLogLevel)
+	}
+
 	return nil
 }