Added optional email cleanup on S3 at end of process

Author: nbcraft

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Change Log for aws-lambda-ses-forwarder
 
+## 4.3.0 [2017/3/10]
+
+- Added optional `cleanupS3Email` step at the end of process
+
 ## 4.2.0 [2017/6/20]
 
 - Removing `Message-ID` header from messages to fix `InvalidParameterValue:

README.md

@@ -88,7 +88,8 @@ the email forwarding mapping from original destinations to new destination.
           "Effect": "Allow",
           "Action": [
              "s3:GetObject",
-             "s3:PutObject"
+             "s3:PutObject",
+             "s3:DeleteObject"
           ],
           "Resource": "arn:aws:s3:::S3-BUCKET-NAME/*"
        }

example/index.js

@@ -16,7 +16,8 @@ exports.handler = function(event, context, callback) {
         "abuse@example.com": [
           "example.jim@example.com"
         ]
-      }
+      },
+      emailCleanupS3: false
     }
   };
   LambdaForwarder.handler(event, context, callback, overrides);

index.js

@@ -27,6 +27,8 @@ console.log("AWS Lambda SES Forwarder // @arithmetric // Version 4.2.0");
 //
 //   To match a mailbox name on all domains, use a key without the "at" symbol
 //   and domain part of an email address (i.e. `info`).
+//
+// - emailCleanupOnS3: true to delete email from S3 bucket
 var defaultConfig = {
   fromEmail: "noreply@example.com",
   subjectPrefix: "",
@@ -46,7 +48,8 @@ var defaultConfig = {
     "info": [
       "info@example.com"
     ]
-  }
+  },
+  emailCleanupOnS3: false
 };
 
 /**
@@ -280,6 +283,34 @@ exports.sendMessage = function(data) {
   });
 };
 
+/**
+ * Clean up (delete) the S3 email object
+ *
+ * @param {object} data - Data bundle with context, email, etc.
+ *
+ * @return {object} - Promise resolved with data.
+ */
+exports.emailCleanupOnS3 = function(data) {
+  data.log({level: "info", message: "Deleting email at s3://" +
+    data.config.emailBucket + '/' + data.config.emailKeyPrefix +
+    data.email.messageId});
+  return new Promise(function(resolve, reject) {
+    data.s3.deleteObject({
+      Bucket: data.config.emailBucket,
+      Key: data.config.emailKeyPrefix + data.email.messageId
+    }, function(err, result) {
+      if (err) {
+        data.log({level: "error", message: "deleteObject() returned error:",
+          error: err, stack: err.stack});
+        return reject(new Error('Error: Email cleanup on S3 failed.'));
+      }
+      data.log({level: "info", message: "emailCleanupOnS3() successful.",
+        result: result});
+      resolve(data);
+    });
+  });
+};
+
 /**
  * Handler function to be invoked by AWS Lambda with an inbound SES email as
  * the event.
@@ -291,14 +322,6 @@ exports.sendMessage = function(data) {
  * configuration, SES object, and S3 object.
  */
 exports.handler = function(event, context, callback, overrides) {
-  var steps = overrides && overrides.steps ? overrides.steps :
-  [
-    exports.parseEvent,
-    exports.transformRecipients,
-    exports.fetchMessage,
-    exports.processMessage,
-    exports.sendMessage
-  ];
   var data = {
     event: event,
     callback: callback,
@@ -309,6 +332,17 @@ exports.handler = function(event, context, callback, overrides) {
     s3: overrides && overrides.s3 ?
       overrides.s3 : new AWS.S3({signatureVersion: 'v4'})
   };
+  var steps = overrides && overrides.steps ? overrides.steps :
+  [
+    exports.parseEvent,
+    exports.transformRecipients,
+    exports.fetchMessage,
+    exports.processMessage,
+    exports.sendMessage
+  ];
+  if (data.config.emailCleanupOnS3) {
+    steps.push(exports.emailCleanupOnS3);
+  }
   Promise.series(steps, data)
     .then(function(data) {
       data.log({level: "info", message: "Process finished successfully."});

package.json

@@ -1,6 +1,6 @@
 {
   "name": "aws-lambda-ses-forwarder",
-  "version": "4.2.0",
+  "version": "4.3.0",
   "description": "Serverless email forwarding using AWS Lambda and SES",
   "main": "index.js",
   "scripts": {

test/emailCleanupOnS3.js

@@ -0,0 +1,62 @@
+
+/* global describe, it */
+
+var assert = require("assert");
+
+var index = require("../index");
+
+describe('index.js', function() {
+  describe('#emailCleanupOnS3()', function() {
+    it('should invoke the AWS S3 SDK to delete the email object',
+      function(done) {
+        var data = {
+          config: {
+            emailBucket: "bucket",
+            emailKeyPrefix: "prefix/",
+            emailCleanupOnS3: true
+          },
+          context: {},
+          email: {
+            messageId: "abc"
+          },
+          log: console.log,
+          s3: {
+            deleteObject: function(options, callback) {
+              callback(null);
+            }
+          }
+        };
+        index.emailCleanupOnS3(data)
+          .then(function() {
+            assert.ok(true, "emailCleanupOnS3 returned successfully");
+            done();
+          });
+      });
+
+    it('should result in failure if the AWS S3 SDK cannot delete the object',
+      function(done) {
+        var data = {
+          config: {
+            emailBucket: "bucket",
+            emailKeyPrefix: "prefix/",
+            emailCleanupOnS3: true
+          },
+          context: {},
+          email: {
+            messageId: "abc"
+          },
+          log: console.log,
+          s3: {
+            deleteObject: function(options, callback) {
+              callback(true);
+            }
+          }
+        };
+        index.emailCleanupOnS3(data)
+          .catch(function(err) {
+            assert.ok(err, "emailCleanupOnS3 aborted operation");
+            done();
+          });
+      });
+  });
+});

test/handler.js

@@ -21,6 +21,9 @@ describe('index.js', function() {
           },
           getObject: function(options, callback) {
             callback(null, {Body: "email data"});
+          },
+          deleteObject: function(options, callback) {
+            callback(null, {});
           }
         },
         ses: {
@@ -35,7 +38,8 @@ describe('index.js', function() {
             "info@example.com": [
               "jim@example.com"
             ]
-          }
+          },
+          emailCleanupOnS3: true
         }
       };
       index.handler(event, context, callback, overrides);