Is it possible/recommended to use `sam build` in AWS CodeBuild? - amazon-web-services

Question

This question spun out of this one. Now that I have a better understanding of what was going wrong there, and a workable, if imperfect, solution, I'm submitting a more focused follow-up (I'm still something of a novice at StackOverflow - please let me know if this contravenes etiquette, and I should follow-up on the original).
This page suggests that "You use AWS CodeBuild to build, locally test, and package your serverless application". However, when I include a sam build command in my buildspec.yml, I get the following log output, suggesting that sam is not installed on CodeBuild images:
[Container] 2018/12/31 11:41:49 Running command sam build --use-container
sh: 1: sam: not found
[Container] 2018/12/31 11:41:49 Command did not exit successfully sam build --use-container exit status 127
[Container] 2018/12/31 11:41:49 Phase complete: BUILD Success: false
[Container] 2018/12/31 11:41:49 Phase context status code: COMMAND_EXECUTION_ERROR Message: Error while executing command: sam build --use-container. Reason: exit status 127
Furthermore, if I install SAM with pip install aws-sam-cli, running sam build --use-container in CodeBuild gives an error. sam build itself succeeds, but since it doesn't install test dependencies, I'd still need to use pip install -r tests/requirements-test.txt -t . to be able to run tests in CodeBuild. Moreover, this suggests that --use-container is required for "packages that have natively compiled programs").
This makes me wonder whether I'm trying to do something wrong. What's the recommended way of building SAM services in a CI/CD workflow on AWS?

Answer 1

2019_10_18 - Update (confirming #Spiff answer above):
Apparently Codebuild now work seamlessly with SAM, that's all I needed in buildspec.yml for a lambda using pandas and psycopg2-binary:
version: 0.2
phases:
install:
runtime-versions:
python: 3.7
pre_build:
commands:
- python -m unittest discover tests
build:
commands:
- sam build
post_build:
commands:
- sam package --output-template-file packaged.yaml --s3-bucket my-code-pipeline-bucketz
artifacts:
type: zip
files:
- packaged.yaml
Cheers

Answer 2

Please see below for buildspec.yaml that works for me when using AWS SAM with AWS CodeBuild, with cloudformation.yml
phases:
build:
commands:
- pip install --user aws-sam-cli
- USER_BASE_PATH=$(python -m site --user-base)
- export PATH=$PATH:$USER_BASE_PATH/bin
- sam build -t cloudformation.yml
- aws cloudformation package --template-file .aws-sam/build/template.yaml --s3-bucket <TARGET_S3_BUCKET> --output-template-file cloudformation-packaged.yaml
- aws s3 cp ./cloudformation-packaged.yaml <TARGET_S3_BUCKET>/cloudformation-packaged.yaml
In the result I get a deployment package and packaged cloudformation template in the TARGET_S3_BUCKET.
For each function in the ./src folder, I have a requirements.txt file that includes all the dependencies, but I dont run pip install -r requirements.txt manually.

Answer 3

If you want to run sam build command in CodeBuild, you must install aws-sam-cli first (probably in the install phase of buildspec.yml file) i.e. by running pip install aws-sam-cli command or alike.
--use-container option in the sam build command will cause the command to pull in the Docker image resembling the AWS Lambda execution environment, then run the container from this Docker image to pip install (if your lambda is written in Python) your function dependencies for creating your lambda deployment package. This will ensure that the lambda function will use native compiled libraries that are compatible with the actual runtime environment of AWS Lambda.
Therefore, if you specify --use-container option for sam build command running in CodeBuild, you also need to make sure that a Docker image used by your CodeBuild build project must support Docker runtime.
The most easiest way is to use CodeBuild build environment named aws/codebuild/standard:2.0 Docker image. Enabling Docker runtime in runtime-versions property in the install phases of your buildspec.yml. Also you might need to enable PrevilegedMode of your CodeBuild project in order to connect with Docker daemon from your build environment.

Answer 4

As of October 2019 I had no issues whatsoever deploying a serverless application with codebuild using sam build,
First of all --user is not needed for pip install aws-sam-cli. In fact including --user appears to be the only reason that sam is not in the path.
In addition the --use-container is not needed either as long as no native libraries are built, like psycopg