Added errorLog feature and updated docs

Author: titans-of-code

.gitignore

@@ -66,4 +66,5 @@ out/
 # OS files #
 .DS_Store
 .svn
-._*
+._*
+/bin/

README.md

@@ -12,31 +12,44 @@ var previousError = getPreviousErrorMessage(error)
     This catches custom service unauthorized error from app and formats the response accordingly.
     */
     "APP:UNAUTHORIZED": {
-        "code":401,
-        "reason": "Unauthorized",
-        "message": error.description
+        code: 401,
+        reason: "Unauthorized",
+        message: error.description
     },
 
     /*
     APP 503 Service Unavailable
     This catches custom service unavailable error from app and formats the response accordingly.
     */
     "APP:SERVICE_UNAVAILABLE": {
-        "code":503,
-        "reason": "Service Unavailable",
-        "message": error.description
+        code: 503,
+        reason: "Service Unavailable",
+        message: error.description
     },
 
     /*
     HTTP 500 Pass Through
     This catches HTTP 500 errors and propagates the detailed reason for failure.
-    It uses the error.message field from the response of the HTTP call that failed, which conforms to the API Error Handler responses.
+    It uses the error.message field from the response of the HTTP call that failed for the message, which conforms to the API Error Handler responses.
     If not found, the error.description will be returned, which generally says an internal server error occurred.
     This useful for process or experience APIs to pass through system API errors.
     */
     "HTTP:INTERNAL_SERVER_ERROR": {
-        "code":500,
-        "reason": "Internal Server Error",
-        "message": if (!isEmpty(previousError)) previousError else error.description
+        code: 500,
+        reason: "Internal Server Error",
+        message: if (!isEmpty(previousError)) previousError else error.description
+    },
+    
+    /*
+    Unknown Errors
+    This catches unknown errors, which includes any non-standard HTTP error status code and propagates the detailed reason for failure.
+    It tries to use the called API's error response code and phrase if available in the error.  If not, it uses the default 500 response.
+    It uses the error.message field from the response of the HTTP call that failed for the message, which conforms to the API Error Handler responses.
+    If not found, the error.description will be returned, which generally says an internal server error occurred.
+    */
+    "MULE:UNKNOWN": {
+        code: error.exception.errorMessage.attributes.statusCode default 500,
+        reason: error.exception.errorMessage.attributes.reasonPhrase default "Internal Server Error",
+        message: if (!isEmpty(previousError)) previousError else error.description
     }
 }

examples/customErrors.dwl

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-	<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 	<modelVersion>4.0.0</modelVersion>
 
 	<groupId>ORG_ID_TOKEN</groupId>
@@ -16,7 +16,7 @@
 
 		<!-- XML SDK properties -->
 		<mule.version>4.3.0</mule.version>
-		<mule.extensions.maven.plugin.version>1.4.0</mule.extensions.maven.plugin.version>
+		<mule.extensions.maven.plugin.version>1.4.1</mule.extensions.maven.plugin.version>
 		<app.runtime>4.3.0</app.runtime>
 	</properties>
 
@@ -71,6 +71,12 @@
 			<url>https://repository.mulesoft.org/snapshots/</url>
 			<layout>default</layout>
 		</repository>
+		<repository>
+			<id>anypoint-exchange-v3</id>
+			<name>Anypoint Exchange V3</name>
+			<url>https://maven.anypoint.mulesoft.com/api/v3/maven</url>
+			<layout>default</layout>
+		</repository>
 	</repositories>
 
 	<pluginRepositories>

exchange-docs/home.md

@@ -146,10 +146,18 @@
 					<ee:set-attributes><![CDATA[%dw 2.0
 						import * from module_error_handler_plugin::common
 						output application/java
-						var code = getError(vars.errorType, vars.defaultErrors, vars.customErrors default {}).code default 500
+						var error = getError(vars.errorType, vars.defaultErrors, vars.customErrors default {})
+						var code = error.code default 500
+						var message = toString(error.message, "Internal Server Error")
+						var previousMessage = toString(vars.previousError)
+						var description = toString(vars.error.description)
+						
+						// Concatenate current error message, previous error message, and error description without duplicates or empties
+						var log = (([message, previousMessage, description] filter !isEmpty($)) distinctBy $) joinBy " | "				
 						---
 						{
-							httpStatus: code as Number
+							httpStatus: code as Number,
+							errorLog: log
 						}]]>
 					</ee:set-attributes>
 				</ee:message>

handlerFlow.png

@@ -5,23 +5,36 @@
     This file must be in the ./resources/<module name> folder in order to be exported in the META-INF/mule-artifact/mule-artifact.json file.  This allows the functions to be used in the module as they are executed in the app's context (without the mule message context).
  */
 
-import mergeWith from dw::core::Objects
-
 // Downstream error pulled off the Mule error object, which conforms to the API Error Handler responses.
 fun getPreviousErrorMessage(error) = error.exception.errorMessage.typedValue.error.message default ""
 
-// Get the error type string
+/*
+ *  Get the error type as a String
+ */
 fun getErrorTypeAsString(errorType) = 
     if (!isBlank(errorType.namespace))
         errorType.namespace ++ ":" ++ (errorType.identifier default "") 
     else
         "UNKNOWN"
 
-// Get the proper error from the merged default and custom error lists.  Provide a standard error if none found.
+/*
+ * Get the proper error from the merged default and custom error lists.  Provide a standard error if none found.
+ */
 fun getError(errorType, defaultErrors, customErrors = {}) = do {
-    var errorList = (defaultErrors mergeWith customErrors)
+	import mergeWith from dw::core::Objects
+    var errorList = (defaultErrors mergeWith (customErrors default {}))
     var foundError = errorList[errorType]
     var error = if ( !isEmpty(foundError) ) foundError else errorList["UNKNOWN"]
     ---
     error
 }
+
+/*
+ * Convert non-empty items to String.  If not a string, then writes in Java format.
+ * If empty, then returns the default value provided
+ */
+fun toString(obj, def="") = obj match {
+    case item if (item is String and !isEmpty(item)) -> item
+    case item if !isEmpty(item) -> write(item, "application/java")
+    else -> def
+}

pom.xml

@@ -3,6 +3,9 @@
   "properties": {
     "httpStatus": {
       "type": "string"
+    },
+    "errorLog": {
+      "type": "string"
     }
   },
   "additionalProperties": false