Deploy Lambda Functions from CLI with Layers

Intermediate15 min

Package and deploy AWS Lambda functions using the CLI, including dependency management through Lambda layers for smaller deployment bundles.

Prerequisites

-AWS CLI v2 installed and configured
-IAM role with Lambda execution permissions
-Node.js or Python runtime available locally

Steps

Package the function code

Create a ZIP archive containing your Lambda function handler and any application-specific modules.

$ zip -r function.zip index.mjs lib/ -x '*.test.*' -x 'node_modules/*'

Exclude test files and node_modules from the function ZIP. Dependencies should go in a layer instead.

Create or update the Lambda function

Deploy the function code ZIP to Lambda. Use create-function for the first deploy, or update-function-code for subsequent deploys.

$ aws lambda update-function-code --function-name my-api-handler --zip-file fileb://function.zip

The fileb:// prefix is required for binary file uploads. Using file:// will corrupt the ZIP.

Package the layer dependencies

Create a layer ZIP with the correct directory structure for your runtime. Node.js expects a nodejs/node_modules path.

$ mkdir -p layer/nodejs && cp package.json layer/nodejs/ && cd layer/nodejs && npm install --omit=dev && cd ../.. && zip -r layer.zip layer/

Lambda layers must follow a specific directory structure: nodejs/node_modules/ for Node.js, python/ for Python.

Publish the Lambda layer

Upload the dependency layer to Lambda. Each publish creates a new immutable version that can be referenced by functions.

$ aws lambda publish-layer-version --layer-name my-api-deps --zip-file fileb://layer.zip --compatible-runtimes nodejs20.x nodejs22.x

Attach the layer to the function

Update the function configuration to reference the new layer version, making the packaged dependencies available at runtime.

$ aws lambda update-function-configuration --function-name my-api-handler --layers arn:aws:lambda:us-east-1:111111111111:layer:my-api-deps:3

You can attach up to 5 layers to a single function. The total unzipped size of function code plus all layers must be under 250 MB.

Test the deployed function

Invoke the Lambda function with a test payload and view the response to confirm the deployment works correctly.

$ aws lambda invoke --function-name my-api-handler --payload '{"path": "/health", "httpMethod": "GET"}' --cli-binary-format raw-in-base64-out response.json && cat response.json

Use --cli-binary-format raw-in-base64-out when passing JSON payloads directly, otherwise the CLI will base64-encode your payload.

Full Script

full-script.sh

#!/bin/bash
# Lambda Deployment with Layers
# Usage: ./deploy-lambda.sh <function-name> <layer-name> <runtime>

set -euo pipefail

FUNCTION_NAME="${1:?Usage: $0 <function-name> <layer-name> <runtime>}"
LAYER_NAME="${2:?Provide your layer name}"
RUNTIME="${3:-nodejs20.x}"

echo "=== Packaging function code ==="
zip -r function.zip index.mjs lib/ -x '*.test.*' -x 'node_modules/*'

echo "=== Deploying function code ==="
aws lambda update-function-code \
  --function-name "$FUNCTION_NAME" \
  --zip-file fileb://function.zip

echo "=== Packaging layer dependencies ==="
rm -rf layer
mkdir -p layer/nodejs
cp package.json layer/nodejs/
cd layer/nodejs && npm install --omit=dev && cd ../..
zip -r layer.zip layer/

echo "=== Publishing layer ==="
LAYER_VERSION=$(aws lambda publish-layer-version \
  --layer-name "$LAYER_NAME" \
  --zip-file fileb://layer.zip \
  --compatible-runtimes "$RUNTIME" \
  --output json | jq -r '.LayerVersionArn')

echo "Published layer: $LAYER_VERSION"

echo "=== Attaching layer to function ==="
aws lambda update-function-configuration \
  --function-name "$FUNCTION_NAME" \
  --layers "$LAYER_VERSION"

echo "=== Waiting for function update ==="
aws lambda wait function-updated --function-name "$FUNCTION_NAME"

echo "=== Testing function ==="
aws lambda invoke \
  --function-name "$FUNCTION_NAME" \
  --payload '{"path": "/health", "httpMethod": "GET"}' \
  --cli-binary-format raw-in-base64-out \
  response.json

echo "Response:"
cat response.json
echo ""

# Cleanup
rm -f function.zip layer.zip response.json
rm -rf layer

echo "Deployment complete."

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#!/bin/bash # Lambda Deployment with Layers # Usage: ./deploy-lambda.sh <function-name> <layer-name> <runtime> set -euo pipefail FUNCTION_NAME="${1:?Usage: $0 <function-name> <layer-name> <runtime>}" LAYER_NAME="${2:?Provide your layer name}" RUNTIME="${3:-nodejs20.x}" echo "=== Packaging function code ===" zip -r function.zip index.mjs lib/ -x '*.test.*' -x 'node_modules/*' echo "=== Deploying function code ===" aws lambda update-function-code \ --function-name "$FUNCTION_NAME" \ --zip-file fileb://function.zip echo "=== Packaging layer dependencies ===" rm -rf layer mkdir -p layer/nodejs cp package.json layer/nodejs/ cd layer/nodejs && npm install --omit=dev && cd ../.. zip -r layer.zip layer/ echo "=== Publishing layer ===" LAYER_VERSION=$(aws lambda publish-layer-version \ --layer-name "$LAYER_NAME" \ --zip-file fileb://layer.zip \ --compatible-runtimes "$RUNTIME" \ --output json | jq -r '.LayerVersionArn') echo "Published layer: $LAYER_VERSION" echo "=== Attaching layer to function ===" aws lambda update-function-configuration \ --function-name "$FUNCTION_NAME" \ --layers "$LAYER_VERSION" echo "=== Waiting for function update ===" aws lambda wait function-updated --function-name "$FUNCTION_NAME" echo "=== Testing function ===" aws lambda invoke \ --function-name "$FUNCTION_NAME" \ --payload '{"path": "/health", "httpMethod": "GET"}' \ --cli-binary-format raw-in-base64-out \ response.json echo "Response:" cat response.json echo "" # Cleanup rm -f function.zip layer.zip response.json rm -rf layer echo "Deployment complete."