How to Install AWS SAM CLI on Windows

Developing serverless applications with Amazon Web Services (AWS) has become extremely popular due to benefits like infinite scalability and zero server management. The AWS Serverless Application Model (SAM) makes building, testing and deploying serverless apps simpler and faster.

In this comprehensive 2600+ word guide, you’ll learn everything you need to get the AWS SAM Command Line Interface (SAM CLI) set up on your Windows machine.

Overview of AWS SAM CLI

The SAM CLI is a command line tool that provides an interface for local development and testing of serverless apps defined as AWS SAM templates.

Key capabilities include:

• Scaffolding a starter SAM project
• Validating SAM template configurations
• Simulating Lambda functions and API endpoints locally
• Building serverless apps using Docker
• Automated deployment to AWS services

Compared to the default AWS CLI which focuses more on management of existing resources, SAM CLI is specifically optimized for CI/CD workflows around serverless application development.

Having the SAM CLI installed enables you to build and test your serverless apps locally before needing to manually deploy them to the AWS cloud repeatedly. This saves immense time and effort compared to traditional deploy-test-debug cycles.

According to AWS, teams using SAM CLI report up to 10x faster development cycles over going straight to the cloud. The increased velocity helps you iterate faster to meet changing requirements.

Key Benefits of Using SAM CLI

Here are some of the most valuable advantages the SAM CLI unlocks for serverless developers on Windows:

1. Local Simulation of Lambda and APIs

The sam local command starts Docker containers to mimic your Lambda functions and API Gateway endpoints on your local machine. This means you can debug and validate your serverless apps without needing to deploy to AWS first.

2. Rapid SAM App Initialization

Use sam init to quickly scaffold a project template with the necessary folder structure, build scripts and SAM configuration to get up and running fast.

3) Repeatable Local Testing

Define automated test events to simulate Lambda function triggers and feed test payload data to catch issues early. No more manual testing effort required!

4) Reliable and Consistent Deployments

SAM CLI manages the complexity of transforming and deploying SAM templates. Deploy serverless stacks to the AWS Cloud in a few CLI commands.

Now that you see the immense value SAM CLI brings to the table, let’s get it installed and set up properly on your Windows machine.

Installation Prerequisites

Before proceeding with the SAM CLI installation, verify that you have the following already configured:

• Windows 10 or higher
• Latest version of Python 3.7+ installed
• Docker Desktop up and running for containerization
• AWS CLI fully set up with credentials

If you need help getting any of those set up, refer to my handy guides for installing Python on Windows and configuring the AWS CLI.

You‘ll also want to have an AWS account ready so you can deploy applications later.

Installing SAM CLI on Windows

Now we‘re ready to install the AWS SAM CLI itself.

There are a couple different installation options available but I recommend using the MSI installer which provides the most seamless experience.

Let‘s go through that process step-by-step:

Download the MSI Installer

1. Go to the SAM CLI download page and click the link for the 64-bit MSI installer under the Windows tab:

2. The installer binary is around 65 MB – download time depends on your internet speed but shouldn‘t take too long.

3. Double click on the downloaded .msi file to launch the installer wizard.

Run the Installer Wizard

The SAM CLI installer wizard will guide you through the setup process:

1. Click through the initial welcome screens

2. Accept the terms in the license agreement

3. Select the destination folder location, default is fine

4. On the settings screen, check the box to Add to PATH environment variable

5. The required components like AWS Toolkit will also be installed automatically.

6. Finally click the Install button to proceed.

The entire installation shouldn‘t take more than a couple of minutes if you accepted the defaults.

Verify the Installation

Once the installer wizard completes, open Command Prompt and run:

sam --version

You should see output with the current SAM CLI version installed:

If you get an error instead, try closing and reopening the Command Prompt window.

You may also need to manually add the SAM CLI installation path e.g. C:\Program Files\Amazon\AWSSAMCLI folder to your system PATH.

And that‘s it for installation! The main SAM CLI executable is now ready to use.

One optional extra step is to upgrade pip and install the aws-sam-cli Python package which enables tab auto-completion.

Run the following pip command for that:

pip install --upgrade aws-sam-cli

Alternative Install Methods

While the MSI installer is the easiest approach, technically you can also install SAM CLI in a couple of other ways:

Install via pip

For Python purists, you can use pip instead to install SAM CLI:

pip install aws-sam-cli

However, this can have downsides like missing dependencies or PATH issues.

Use a Package Manager

On Linux/macOS it‘s common to use native package managers for installing developer tools.

For Windows, Chocolatey or Scoop can be used to install the SAM CLI.

But again, they may have quirks vs the official MSI.

Run the AWS SAM Docker Image

You can actually avoid installing SAM CLI locally by running it as a Docker container instead:

docker run -v "$(pwd):/app" --rm -it public.ecr.aws/sam/build-python3.9:latest

However this only really makes sense in automated pipelines vs developer workstations.

Overall for most Windows users, the .msi installer provides the smoothest experience which is why I recommend sticking with it.

Troubleshooting SAM CLI Installation Issues

In most cases SAM CLI will install without any major hiccups.

But occasionally you may run into an odd error or unexpected behavior like:

• CLI commands not recognized

• Docker failing to run SAM properly

• Permissions issues with CloudFormation

Here are some common troubleshooting fixes:

Restart Your Terminal

If running sam --version returns a command not found error, first restart your Command Prompt/PowerShell completely and try again. This picks up newly updated PATH directories.

Check Path Environment Variables

Double check that your Windows PATH has the correct SAM CLI folder such as C:\Program Files\Amazon\AWSSAMCLI added. If not, manually append it.

Install AWS CLI First

Sometimes SAM CLI has issues recognizing credentials or permissions properly. Explicitly installing the latest AWS CLI before SAM CLI can resolve it.

Upgrade Docker Desktop

Old Docker versions may be incompatible with SAM. Upgrade Docker if container builds or simulations fail unexpectedly.

Reinstall Python Packages

When in doubt, running pip install --upgrade aws-sam-cli awscli boto3 will refresh all the underlying Python packages.

Uninstall Completely First

If other fixes don‘t help, fully uninstall then reinstall the SAM CLI cleanly from scratch.

And as always – Google is your friend! The AWS forums are also great troubleshooting resources.

Using the AWS SAM CLI

I‘ll briefly cover some SAM CLI basics now so you can validate it‘s working properly.

Full details are in my Complete Guide to AWS SAM CLI – but here‘s a quick demo to initialize a serverless app:

First cd into a working directory then run:

sam init

This scaffolds a Hello World app as a starting point:

Look in that directory and you‘ll see boilerplate SAM configuration generated along with code for a basic Lambda function triggered by API Gateway.

To run the API locally, execute:

sam local start-api  

This spins up Docker containers emulating API Gateway which you can hit from your browser on port 3000.

Modify the function code and templates then restart to validate changes. Once working smoothly locally, you can use sam deploy to ship to AWS.

This is just the tip of the iceberg in terms of SAM CLI functionality – but verifies your installation is ready for serverless development!

You may also want to page through the SAM CLI Cheatsheet I put together for all the common commands.

Additional SAM CLI Resources

To learn more about getting the most from SAM CLI, here some extra references:

• Official SAM CLI Documentation – Amazon‘s guides go deep into syntax etc
• Serverless Stack Blog – Fantastic frameworks, patterns and examples using SAM
• Learn AWS SAM Course – Classes focused specifically on SAM CLI Mastery
• SAM CLI Example Repos – AWS code samples for SAM CLI integrations

This guide should have you set up with a solid SAM CLI foundation. Where you go from here depends on your serverless architecture aspirations!

I‘m always happy to answer any AWS SAM questions in the comments below.