Manage AWS Lambda Environment Variables with CLI Shell Script

In this blog post, I introduce a script that allows you to efficiently manage the environment variables of an AWS Lambda function.

This script provides the capability to:

1. Register a new variable: Add a new environment variable to the Lambda function.
2. Update an existing variable: Modify the value of an existing environment variable.
3. Delete a variable: Remove an environment variable from the Lambda function.

Important Note on Updating Environment Variables

When using the aws lambda update-function-configuration command to update the existing environment variables, it is crucial to pass both the environment variable you want to add or update and all existing environment variables. Failing to do so will result in the deletion of the existing environment variables. The script provided in this blog post takes this into consideration and ensures the proper handling of environment variables during the update process.

Parameters

function_name: The name of the Lambda function.

region: The AWS region where the Lambda function is deployed.

env_vars_upsert: Key-value pairs of environment variables to be upserted (updated or inserted).

• During the upsert process, the environment variable will be updated if it exists; otherwise, a new one will be registered.

• You can include any number of key-value pairs.
  

env_vars_upsert=(
  "MY_ENV1" "value1"
  "MY_ENV2" "value2"
)

env_vars_remove: Keys of environment variables to be removed.

• If the specified key does not exist, nothing will happen.

env_vars_remove=("MY_ENV3" "MY_ENV4")

	#!/bin/bash
	# This script updates AWS Lambda environment variables using the AWS CLI.
	# It can add or update environment variables, and remove specified variables.
	#
	# Parameters:
	# function_name: The name of the Lambda function you want to update
	# region: The AWS region where your Lambda function is located
	# env_vars_key_value_upsert: An array containing key-value pairs of environment variables to add or update
	# env_vars_key_remove: An array containing keys of environment variables to remove
	# Set the region variable
	region="ap-northeast-1"
	# Set your function name directly in the script
	function_name="your_lambda_function_name"
	# Define your environment variables as key-value pairs to add or update
	env_vars_key_value_upsert=(
	"MY_ENV1" "value1"
	"MY_ENV2" "value2"
	)
	# Specify environment variables to remove
	env_vars_key_remove=("MY_ENV3" "MY_ENV4")
	# Retrieve the existing environment variables
	existing_env_vars=$(aws lambda get-function-configuration \
	--function-name "$function_name" \
	--region "$region" \
	--query 'Environment.Variables' \
	--output json)
	# Update or insert new environment variables
	updated_env_vars="$existing_env_vars"
	for ((i = 0; i < ${#env_vars_key_value_upsert[@]}; i+=2)); do
	updated_env_vars=$(echo "$updated_env_vars" \
	| jq --arg key "${env_vars_key_value_upsert[$i]}" --arg value "${env_vars_key_value_upsert[$i + 1]}" \
	'.[$key] = $value')
	done
	# Remove specified environment variables
	for key in "${env_vars_key_remove[@]}"; do
	updated_env_vars=$(echo "$updated_env_vars" \
	| jq --arg key "$key" \
	'del(.[$key])')
	done
	# Update the Lambda function configuration with the new environment variables
	aws lambda update-function-configuration \
	--function-name "$function_name" \
	--environment "{\"Variables\": $updated_env_vars}" \
	--region "$region"

view raw change_lambda_env_variables.sh hosted with ❤ by GitHub

Output

The script will response in JSON format. The "Environment" section will display the updated state of the environment variables.

{
    "FunctionName": "xxxx",
    ...

    "Environment": {
        "Variables": {
            "MY_ENV2": "value2",
            "MY_ENV1": "value1"
        }
    },
    ...
}

Summary

I introduced a shell script for managing AWS Lambda environmental variables, enabling users to register, update, and delete variables with ease. This script also takes into consideration the prevention of accidental deletions, ensuring safe and efficient management of your Lambda function's environmental variables.

Caution

Before using this script in a production environment, please create a test Lambda function and test it thoroughly to ensure it works as expected.