> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/continuous-delivery/3.0/use-deployments/overview-5/sam-build.md).

# SAM Build

Reference for the AWS SAM Build step — builds an AWS SAM application inside a Lambda-compatible container using sam build.

### What you will learn <a href="#what-you-will-learn" id="what-you-will-learn"></a>

* What fields are available on the SAM Build step, which are required, and which are optional overrides.
* How to configure the `--use-container` flag and Docker registry credentials for container-based builds.

***

The SAM Build step runs `sam build` against the downloaded SAM directory manifest. When `--use-container` is set in the command options, the build runs inside a Lambda-compatible Docker container provided by the DinD background step. The step outputs the packaged application to `.aws-sam/build/` for the SAM Deploy step to use.

***

### Settings <a href="#settings" id="settings"></a>

The following fields are available in the SAM Build step.

| Field                        | Required | Description                                                                                                                                    |
| ---------------------------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------- |
| **Template File Path**       | Optional | Path to the SAM template file relative to the SAM directory root, for example `template.yaml`. Defaults to `template.yaml`.                    |
| **Command Options**          | Optional | Flags passed to `sam build`. Include `--use-container` to build Lambda packages inside a Lambda-compatible container.                          |
| **Pre-Execute Command**      | Optional | Shell command to run before `sam build`, for example `npm install`. Useful for installing dependencies the build requires.                     |
| **Working Directory**        | Optional | Working directory for the build. Derived from the service configuration.                                                                       |
| **AWS Connector**            | Yes      | A Harness AWS connector with CloudFormation and S3 permissions. Derived from the infrastructure definition.                                    |
| **Region**                   | Yes      | The AWS region for the build, for example `us-east-1`. Derived from the infrastructure definition.                                             |
| **Docker Retry Count**       | Optional | Number of times Harness polls for a running Docker daemon before starting. Default: `3`. Requires the DinD background step.                    |
| **Docker Registry URL**      | Optional | URL of the registry for the Lambda runtime build container, for example `https://index.docker.io/v2/`. Required when `--use-container` is set. |
| **Docker Registry Username** | Optional | Username for the container registry.                                                                                                           |
| **Docker Registry Password** | Optional | Secret reference for the container registry password.                                                                                          |
| **Command Timeout**          | Optional | Maximum time the step can run before Harness marks it failed, for example `10m`.                                                               |
| **Log Level**                | Optional | Logging verbosity for the step. Default: `info`.                                                                                               |
| **Container Registry**       | Optional | Harness connector for the registry that hosts the SAM plugin container image. Leave empty to use the default image from Docker Hub.            |
| **Image**                    | Optional | Container image for the SAM Build step. Defaults to `harnessdev/aws-sam-dev:0.0.12`.                                                           |

{% hint style="info" %}
**`--USE-CONTAINER` REQUIREMENT**

Include `--use-container` in **SAM Build Command Options** to build Lambda packages inside a container that matches the Lambda execution environment. Without this flag, SAM builds on the host directly and may produce packages incompatible with the Lambda runtime.
{% endhint %}

***

### Step YAML <a href="#step-yaml" id="step-yaml"></a>

```yaml
- name: AWS SAM Build
  id: awsSamBuildStep
  template:
    uses: awsSamBuildStep
    with:
      connector: <aws-connector>
      region: <aws-region>
      stack: <cloudformation-stack-name>
      cmd_opts: --use-container
      docker_retry_count: '3'
      registry_url: https://index.docker.io/v2/
      registry_username: <registry-username>
      registry_pwd: <registry-password-secret>
```

***

### Next steps <a href="#next-steps" id="next-steps"></a>

* Go to [SAM Deploy](/continuous-delivery/3.0/use-deployments/overview-5/sam-deploy.md) for the deploy step reference.
* Go to [AWS SAM overview](/continuous-delivery/3.0/use-deployments/overview-5.md) for the full stage setup and runtime configuration.
* Go to [SAM services](/continuous-delivery/3.0/use-deployments/overview-5/sam-services.md) for manifest and values.yaml configuration.

{% @harness-feedback/feedback %}