Added Lambda environment variable

Author: alfonsof

awslambdas3copy-rapi/README.md

@@ -19,15 +19,20 @@ It handles an AWS Lambda function that copies an object when it appears in a S3
 
 ## Using the code
 
-* You can select the destination bucket name changing the value of `DESTINATION_BUCKET` variable in the code.
+* You can select the destination bucket name using an AWS Lambda environment variable: `TARGET_BUCKET`
 
 * Access the AWS console.
 
 * Create a S3 bucket for the source and another S3 bucket for the target.
 
-* Create an IAM Policy: ex. `Policy-VM-buckets`
+* Create an IAM Policy: ex. `Policy-my-buckets`
 
- Content of the IAM policy:
+ Changing: 
+ 
+ * `sourcebucket` to the name of your source bucket.
+ * `targetbucket` to the name of your target bucket.
+
+ Content of the IAM policy:
 
  ```bash
  {
@@ -39,7 +44,7 @@ It handles an AWS Lambda function that copies an object when it appears in a S3
  "s3:GetObject"
  ],
  "Resource": [
- "arn:aws:s3:::sourcevm/*"
+ "arn:aws:s3:::sourcebucket/*"
  ]
  },
  {
@@ -48,11 +53,10 @@ It handles an AWS Lambda function that copies an object when it appears in a S3
  "s3:PutObject"
  ],
  "Resource": [
- "arn:aws:s3:::targetvm/*"
+ "arn:aws:s3:::targetbucket/*"
  ]
  },
  {
- "Sid": "Stmt1430872844000",
  "Effect": "Allow",
  "Action": [
  "cloudwatch:*"
@@ -62,7 +66,6 @@ It handles an AWS Lambda function that copies an object when it appears in a S3
  ]
  },
  {
- "Sid": "Stmt1430872852000",
  "Effect": "Allow",
  "Action": [
  "logs:*"
@@ -75,15 +78,15 @@ It handles an AWS Lambda function that copies an object when it appears in a S3
  }
  ```
 
-* Create a role: `Role-VM-buckets`.
+* Create a role: `Role-my-buckets`.
 
- This role uses the policy `Policy-VM-buckets`
+ This role uses the policy `Policy-my-buckets`
 
 * Create an AWS lambda function.
  * Name: `<LAMBDA_NAME>`
- * Runtime: `Python 3.6`
+ * Runtime: `Python 3.8`
  * Handler: `lambda_function.lambda_handler`
- * Role: `Role-VM-buckets`
+ * Role: `Role-my-buckets`
  * The triggers:
  * `S3`
  * Bucket: `<BUCKET_NAME>`
@@ -93,14 +96,15 @@ It handles an AWS Lambda function that copies an object when it appears in a S3
  * `Amazon CloudWatch`
  * `Amazon CloudWatch Logs`
  * `Amazon S3`
- * Lambda obtained information from the policy statements: `Managed policy Policy-VM-buckets`:
- * `s3:GetObject` --> `Allow: arn:aws:s3:::sourcevm/*`
- * `s3:DeleteObject` --> `Allow: arn:aws:s3:::sourcevm/*`
- * `s3:PutObject` --> `Allow: arn:aws:s3:::targetvm/*`
+ * Lambda obtained information from the policy statements: `Managed policy Policy-my-buckets`:
+ * `s3:GetObject` --> `Allow: arn:aws:s3:::sourcebucket/*`
+ * `s3:PutObject` --> `Allow: arn:aws:s3:::targetbucket/*`
  * Basic Settings for the lambda function:
  * Memory (MB): `1024`
  * Timeout: `10 sec`
 
+* Create the AWS Lambda environment variable `TARGET_BUCKET` and set its value to the name of your target bucket.
+
 * Write the code.
 
  The content of `lambda_function.py` file.
@@ -114,3 +118,14 @@ It handles an AWS Lambda function that copies an object when it appears in a S3
  Copy a file in the source S3 bucket.
 
  The object from the source S3 bucket should be copied to the target S3 bucket.
+
+ You should see the next messages in the log:
+
+ ```bash
+ "From - bucket:: <SOURCE_BUCKET_NAME>"
+ "From - object: <SOURCE_FILE_NAME>"
+ "To - bucket: <TARGET_BUCKET_NAME>"
+ "To - object: <TARGET_FILE_NAME>"
+ "Copying object ..."
+ "Copied"
+ ```

awslambdas3copy-rapi/lambda_function.py

@@ -3,18 +3,22 @@
 # in a S3 bucket to another S3 bucket.
 # It uses Resource API (high-level) of Boto3.
 
+import os
 import boto3
 import botocore
 
 # Instantiate the service resource object
 s3_resource = boto3.resource('s3')
 
 def lambda_handler(event, context):
- DESTINATION_BUCKET = 'targetvm' # Destination bucket name
-
  source_bucket_name = event['Records'][0]['s3']['bucket']['name']
  source_key = event['Records'][0]['s3']['object']['key']
- destination_bucket_name = DESTINATION_BUCKET
+ # Retrieve environment variable TARGET_BUCKET
+ destination_bucket_name = os.environ.get('TARGET_BUCKET', None)
+ if destination_bucket_name is None:
+ # Environment variable TARGET_BUCKET does not exist
+ print('Error: TARGET_BUCKET Lambda environment variable does not exist!!')
+ return
  destination_key = source_key
  print('From - bucket: ' + source_bucket_name)
  print('From - object: ' + source_key)