Merge pull request #5 from cmachler/dev

Using Lambda Environment Variable to Define Regions

Author: Chris Machler

README.md

@@ -57,9 +57,27 @@ Next create an IAM role also called "ebs-backup-worker" selete "AWS Lambda" as t
 }
 ```
 
-## Edit the scripts to add appropriate regions for your environment.
+## Add the regions you want run the scripts against as a Python Base64 encoded string Lambda environment variable "aws_regions".
 
-Edit the `regions` list.
+Since Lambda does not allow commas in the environment variable values, we cannot enter in a list for our regions we want to run the script against. To work around this we will Base64 encode the list/string, and then decode the string in our script and then "split" the string into a list again.
+
+Below is an example of using Python to Base64 encode our string:
+
+```
+~$ python
+Python 2.7.12 (default, Nov 19 2016, 06:48:10)
+[GCC 5.4.0 20160609] on linux2
+Type "help", "copyright", "credits" or "license" for more information.
+>>> import base64
+>>> encoded = base64.b64encode(b'us-west-2,us-east-2')
+>>> encoded
+'dXMtd2VzdC0yLHVzLWVhc3QtMg=='
+>>> data = base64.b64decode(encoded)
+>>> data
+'us-west-2,us-east-2'
+>>>
+```
+**We will copy the encoded value and add it as the Lambda environment variable "aws_regions". When copying the encoded value please omit the single quotes in the output (ie. dXMtd2VzdC0yLHVzLWVhc3QtMg==).**
 
 ## Create the Lambda Functions
 

lambda-ebs-backup-cleanup.py

@@ -1,8 +1,10 @@
 import boto3
 import re
 import datetime
+import base64
+import os
 
-regions = ['us-west-2','us-east-2']
+base64_region = os.environ['aws_regions']
 
 iam = boto3.client('iam')
 
@@ -13,6 +15,11 @@
 """
 
 def lambda_handler(event, context):
+    decoded_regions = base64.b64decode(base64_region)
+    regions = decoded_regions.split(',')
+
+    print "Cleaning up snapshots in regions: %s" % regions
+
     for region in regions:
         ec = boto3.client('ec2', region_name=region)
         account_ids = list()

lambda-ebs-backup.py

@@ -1,10 +1,17 @@
 import boto3
 import collections
 import datetime
+import base64
+import os
 
-regions = ['us-west-2','us-east-2']
+base64_region = os.environ['aws_regions']
 
 def lambda_handler(event, context):
+    decoded_regions = base64.b64decode(base64_region)
+    regions = decoded_regions.split(',')
+
+    print "Backing up instances in regions: %s" % regions
+
     for region in regions:
         ec = boto3.client('ec2', region_name=region)
         reservations = ec.describe_instances(