FR: Add simple message types validators for the WRP messages

CHANGELOG.md

@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+- Add simple message types WRP validators [#85](https://github.com/xmidt-org/wrp-go/pull/85)
+- Add basic WRP spec validators [#84](https://github.com/xmidt-org/wrp-go/pull/84)
+- Introduce WRP Validation Framework [#80](https://github.com/xmidt-org/wrp-go/pull/80)
 
 ## [v3.1.3]
 - Fix `500 Invalid WRP content type` for invalid `Accept` headers [#74](https://github.com/xmidt-org/wrp-go/pull/74)

messages.go

@@ -17,12 +17,17 @@
 
 package wrp
 
-import "regexp"
+import (
+	"reflect"
+	"regexp"
+)
 
 //go:generate go install github.com/ugorji/go/codec/codecgen@latest
 //go:generate codecgen -st "json" -o messages_codec.go messages.go
 
 var (
+	// messageReflectType is the cached reflection lookup for Message
+	messageReflectType = reflect.TypeOf(Message{})
 	// eventPattern is the precompiled regex that selects the top level event
 	// classifier
 	eventPattern = regexp.MustCompile(`^event:(?P<event>[^/]+)`)

simpleMessageTypes_validator.go

@@ -0,0 +1,111 @@
+/**
+ *  Copyright (c) 2022  Comcast Cable Communications Management, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package wrp
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+
+	"go.uber.org/multierr"
+)
+
+var (
+	ErrorNotSimpleResponseRequestType = NewValidatorError(errors.New("not simple response request message type"), []string{"Type"}, "")
+	ErrorNotSimpleEventType           = NewValidatorError(errors.New("not simple event message type"), []string{"Type"}, "")
+	ErrorInvalidSpanLength            = NewValidatorError(errors.New("invalid span length"), []string{"Spans"}, "")
+	ErrorInvalidSpanFormat            = NewValidatorError(errors.New("invalid span format"), []string{"Spans"}, "")
+)
+
+// spanFormat is a simple map of allowed span format.
+var spanFormat = map[int]string{
+	// parent is the root parent for the spans below to link to
+	0: "parent",
+	// name is the name of the operation
+	1: "name",
+	// start time of the operation.
+	2: "start time",
+	// duration is how long the operation took.
+	3: "duration",
+	// status of the operation
+	4: "status",
+}
+
+// SimpleEventValidators ensures messages are valid based on
+// each validator in the list. SimpleEventValidators validates the following:
+// UTF8 (all string fields), MessageType is valid, Source, Destination, MessageType is of SimpleEventMessageType.
+func SimpleEventValidators() Validators {
+	return Validators{SpecValidators()}.AddFunc(SimpleEventTypeValidator)
+}
+
+// SimpleResponseRequestValidators ensures messages are valid based on
+// each validator in the list. SimpleResponseRequestValidators validates the following:
+// UTF8 (all string fields), MessageType is valid, Source, Destination, Spans, MessageType is of
+// SimpleRequestResponseMessageType.
+func SimpleResponseRequestValidators() Validators {
+	return Validators{SpecValidators()}.AddFunc(SimpleResponseRequestTypeValidator, SpansValidator)
+}
+
+// SimpleResponseRequestTypeValidator takes messages and validates their Type is of SimpleRequestResponseMessageType.
+func SimpleResponseRequestTypeValidator(m Message) error {
+	if m.Type != SimpleRequestResponseMessageType {
+		return ErrorNotSimpleResponseRequestType
+	}
+
+	return nil
+}
+
+// TODO Do we want to include SpanParentValidator? SpanParent currently doesn't exist in the Message Struct
+
+// SpansValidator takes messages and validates their Spans.
+func SpansValidator(m Message) error {
+	var err error
+	// Spans consist of individual Span(s), arrays of timing values.
+	for _, s := range m.Spans {
+		if len(s) != len(spanFormat) {
+			err = multierr.Append(err, ErrorInvalidSpanLength)
+			continue
+		}
+
+		for i, j := range spanFormat {
+			switch j {
+			// Any nonempty string is valid
+			case "parent", "name":
+				if len(s[i]) == 0 {
+					err = multierr.Append(err, fmt.Errorf("%w %v: invalid %v component '%v'", ErrorInvalidSpanFormat, s, j, s[i]))
+				}
+			// Must be an integer
+			case "start time", "duration", "status":
+				if _, atoiErr := strconv.Atoi(s[i]); atoiErr != nil {
+					err = multierr.Append(err, fmt.Errorf("%w %v: invalid %v component '%v': %v", ErrorInvalidSpanFormat, s, j, s[i], atoiErr))
+				}
+			}
+		}
+	}
+
+	return err
+}
+
+// SimpleEventTypeValidator takes messages and validates their Type is of SimpleEventMessageType.
+func SimpleEventTypeValidator(m Message) error {
+	if m.Type != SimpleEventMessageType {
+		return ErrorNotSimpleEventType
+	}
+
+	return nil
+}