AWS Lambda Deploy Script - Auto-Find CDK Function Names

Problem

CDK appends a hash to Lambda function names (MyFunction-a1b2c3d4). You have to check the console every time to find the exact name before deploying.

Solution

#!/bin/bash
set -euo pipefail

FUNCTION_NAME="${1:?Usage: deploy.sh <function-name>}"
REGION="ap-northeast-2"

ACTUAL_FN=$(aws lambda list-functions \
  --region "$REGION" \
  --query "Functions[?starts_with(FunctionName, '${FUNCTION_NAME}')].FunctionName" \
  --output text)

if [ -z "$ACTUAL_FN" ]; then
  echo "Error: No Lambda function found with prefix '$FUNCTION_NAME'"
  exit 1
fi

echo "Found: $ACTUAL_FN"

npm run build
cd dist && zip -r ../deploy.zip . && cd ..

aws lambda update-function-code \
  --function-name "$ACTUAL_FN" \
  --zip-file "fileb://deploy.zip" \
  --region "$REGION"

echo "Deployed to $ACTUAL_FN"
rm deploy.zip

Key Points

• JMESPath starts_with() in --query finds functions by prefix. No need to know the CDK-appended hash.
• set -euo pipefail stops execution on any error. Prevents deploying after a failed build.
• fileb:// is the AWS CLI protocol for binary files. Different from file:// — zip files must use fileb://.