Step 2.1: Create the deployment package

Currently the example code for the Lambda function is only supplied in Python.

Python

The following example Python code reads and writes an item to your #ELC; cluster. Copy the code and save it into a file called app.py.


from __future__ import print_function
import time
import uuid
import sys
import socket
import elasticache_auto_discovery
from pymemcache.client.hash import HashClient

# ElastiCache settings
elasticache_config_endpoint = "your-elasticache-cluster-endpoint:port"
nodes = elasticache_auto_discovery.discover(elasticache_config_endpoint)
nodes = map(lambda x: (x[1], int(x[2])), nodes)
memcache_client = HashClient(nodes)

######
# This function puts into memcache and get from it.
# Memcached is hosted using elasticache
######
def handler(event, context):

    # Create a random UUID... this will be the sample element we add to the cache.
    uuid_in = uuid.uuid4().hex
    
    # Put the UUID to the cache.
    memcache_client.set('uuid', uuid_in)
    
    # Get the item (UUID) from the cache.
    uuid_out = memcache_client.get('uuid')
    
    # Print the results
    if uuid_out == uuid_in:
        # this print should see the CloudWatch Logs and Lambda console.
        print "Success: Inserted: %s. Fetched %s from memcache." %(uuid_in, uuid_out)
    else:
        raise Exception("Bad value retrieved :(. Expected %s got %s." %(uuid_in, uuid_out)) 

    return "Fetched value from Memcached"

The preceeding code depends upon the pymemcache and elasticache-auto-discovery libraries. Install these libraries using pip.

pymemcache—The Lambda function code uses this library (see pymemcache) to create a HashClient object which sets and gets items from Memcached.
elasticache-auto-discovery—The Lambda function uses this library (see elasticache-auto-discovery) to get the nodes in your Amazon ElastiCache cluster.

Save the preceding Python code in a file named app.py. Then zip all of these files into a file named app.zip to create your deployment package. For step-by-step instructions, see Creating a Deployment Package (Python).

Next Step

Step 2.2: Create the IAM role (execution role)

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Step 2: Create a Lambda function

Step 2.2: Create the IAM role (execution role)