sam build Fails in `examples/fastapi` Due to Missing Image Digest – Manual Docker Pull Required

[DhanukaSheyamPerera]

Description

Running sam build in the examples/fastapi directory results in the following error:

(.venv) dhanuka@Dhanukas-MacBook-Pro metana-platform-file-handling-sam-app % sam build
Building codeuri: /Users/dhanuka/Development/github_repositories/metana-platform-file-handling-sam-app runtime: None architecture: x86_64 functions: FastAPIFunction                                                                                                                                                          
Building image for FastAPIFunction function                                                                                                                                                                                                                                                                                   
Setting DockerBuildArgs for FastAPIFunction function                                                                                                                                                                                                                                                                          
Failed building function FastAPIFunction                                                                                                                                                                                                                                                                                      
Step 1/8 : FROM public.ecr.aws/docker/library/python:3.12-slim
3.12-slim: Pulling from docker/library/python 
f5cc5422ebcb: Pull complete 
e3586b415667: Pull complete 
59e22667830b: Pull complete 
4c665aba06d1: Pull complete 
Status: Downloaded newer image for public.ecr.aws/docker/library/python:3.12-slim ---> 9c1d9ed7593f
Step 2/8 : COPY --from=public.ecr.aws/awsguru/aws-lambda-adapter:0.9.1 /lambda-adapter /opt/extensions/lambda-adapter
0.9.1: Pulling from awsguru/aws-lambda-adapter 
134595beb8b0: Pull complete 
Status: Downloaded newer image for public.ecr.aws/awsguru/aws-lambda-adapter:0.9.1failed to export image: NotFound: content digest sha256:1efc3eb71726bfb67ec3c8e7359e30b6fbf840611bf078fa44050b613b40b820: not found

Build Failed
Error: failed to export image: NotFound: content digest sha256:1efc3eb71726bfb67ec3c8e7359e30b6fbf840611bf078fa44050b613b40b820: not found

This occurs during the Docker build step when executing:

COPY --from=public.ecr.aws/awsguru/aws-lambda-adapter:0.9.1 /lambda-adapter /opt/extensions/lambda-adapter

Temporary Solution

Manually pulling both required Docker images resolves the issue:

docker pull public.ecr.aws/docker/library/python:3.12-slim
docker pull public.ecr.aws/awsguru/aws-lambda-adapter:0.9.1

After doing this, sam build completes successfully.

[bnusunny]

Thanks for reporting this issue. I will take a look today.

[zhanghongshen-amazon]

same issue as mentioned before. The temporary solution works.

[bnusunny]

@DhanukaSheyamPerera Can you share the model of your Macbook and SAM CLI version? The example is for x86_64 architecture. If your Macbook has Apple Chip, which is ARM64 architecture, there might be a platform mismatch that SAM CLI couldn't handle.

[DhanukaSheyamPerera]

Hey @bnusunny,

• MacBook version: - MacBook Pro M3 Pro (macOS Sequoia 15.5)
• SAM CLI version: - 1.142.1

SAM CLI was installed through Homebrew.