Can bash script be written inside a AWS Lambda function

Question

Can I write a bash script inside a Lambda function? I read in the aws docs that it can execute code written in Python, NodeJS and Java 8.

It is mentioned in some doc

Answer 1

AWS supports custom runtimes now based on this announcement here. I already tested bash script and it worked. All you need is to create a new lambda and choose runtime of type Custom it will create the following file structure:

mylambda_func
 |- bootstrap 
 |- function.sh 

Example Bootstrap:

#!/bin/sh

set -euo pipefail

# Handler format: .
# The script file .sh  must be located in
# the same directory as the bootstrap executable.
source $(dirname "$0")/"$(echo $_HANDLER | cut -d. -f1).sh"

while true
do
    # Request the next event from the Lambda Runtime
    HEADERS="$(mktemp)"
    EVENT_DATA=$(curl  -v -sS  -LD "$HEADERS"  -X GET  "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/next")
    INVOCATION_ID=$(grep -Fi Lambda-Runtime-Aws-Request-Id "$HEADERS" | tr -d '[:space:]' | cut -d: -f2)

    # Execute the handler function from the script
    RESPONSE=$($(echo "$_HANDLER" | cut -d. -f2) "$EVENT_DATA")

    # Send the response to Lambda Runtime
    curl  -v  -sS  -X POST  "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/$INVOCATION_ID/response"  -d "$RESPONSE"
done

Example handler.sh:

function handler () {
    EVENT_DATA=$1

    RESPONSE="{\"statusCode\": 200, \"body\": \"Hello from Lambda!\"}"
    echo $RESPONSE
}

P.S. However in some cases you can't achieve what's needed because of the environment restrictions, such cases need AWS Systems Manager to Run command, OpsWork (Chef/Puppet) based on what you're more familiar with or periodically using ScheduledTasks in ECS cluster.

More Information about bash and how to zip and publish it, please check the following links:

• https://docs.aws.amazon.com/en_us/lambda/latest/dg/runtimes-walkthrough.html
• https://docs.aws.amazon.com/lambda/latest/dg/runtimes-custom.html