AWS CodeBuild not pausing on breakpoint - amazon-web-services

Question

Using steps provided here, I kicked off a CodeBuild with the following advanced options checked:
Enable session connection
Allow AWS CodeBuild to modify this service role so it can be used with this build project
The buildspec included a codebuild-breakpoint:
version: 0.2
phases:
pre_build:
commands:
- ls -al
- codebuild-breakpoint
- cd "${SERVICE_NAME}"
- ls -al
- $(aws ecr get-login)
- TAG="$SERVICE_NAME"
build:
commands:
- docker build --tag "${REPOSITORY_URI}:${TAG}" .
post_build:
commands:
- docker push "${REPOSITORY_URI}:${TAG}"
- printf '{"tag":"%s"}' $TAG > ../build.json
artifacts:
files: build.json
The build started and produced the following logs without pausing:
[Container] 2022/02/28 13:49:03 Entering phase PRE_BUILD
[Container] 2022/02/28 13:49:03 Running command ls -al
total 148
drwxr-xr-x 2 root root 4096 Feb 28 13:49 .
drwxr-xr-x 3 root root 4096 Feb 28 13:49 ..
-rw-rw-rw- 1 root root 1818 Feb 28 10:54 user-manager\Dockerfile
-rw-rw-rw- 1 root root 140 Feb 28 10:34 user-manager\body.json
-rw-rw-rw- 1 root root 0 Feb 28 10:54 user-manager\shared-modules\
-rw-rw-rw- 1 root root 4822 Feb 21 14:52 user-manager\shared-modules\config-helper\config.js
-rw-rw-rw- 1 root root 2125 Feb 21 14:52 user-manager\shared-modules\config-helper\config\default.json
-rw-rw-rw- 1 root root 366 Feb 21 14:52 user-manager\shared-modules\config-helper\package.json
-rw-rw-rw- 1 root root 9713 Feb 21 14:52 user-manager\shared-modules\dynamodb-helper\dynamodb-helper.js
-rw-rw-rw- 1 root root 399 Feb 21 14:52 user-manager\shared-modules\dynamodb-helper\package.json
-rw-rw-rw- 1 root root 451 Feb 21 14:52 user-manager\shared-modules\token-manager\package.json
-rw-rw-rw- 1 root root 13885 Feb 21 14:52 user-manager\shared-modules\token-manager\token-manager.js
-rw-rw-rw- 1 root root 44372 Feb 28 10:34 user-manager\src\cognito-user.js
-rw-rw-rw- 1 root root 706 Feb 28 10:34 user-manager\src\package.json
-rw-rw-rw- 1 root root 32734 Feb 28 10:34 user-manager\src\server.js
[Container] 2022/02/28 13:49:03 Running command codebuild-breakpoint
2022/02/28 13:49:03 Build is paused temporarily and you can use codebuild-resume command in the session to resume this build
[Container] 2022/02/28 13:49:03 Running command cd "${SERVICE_NAME}"
/codebuild/output/tmp/script.sh: 4: cd: can't cd to user-manager
My primary question is: Why didn't the build pause and session manager link become available?
Side-quest: The reason I'm trying to debug the session is to try to determine why the process can't CD to the user-manager folder (which clearly exists). Any ideas why?

Answer 1

TLDR: The image on the build machine was too old.
Main quest
The template specified aws/codebuild/ubuntu-base:14.04 as the CodeBuild image. Presumably that image pre-dated the Session Manager functionality (which requires a specific version of the SSM agent to be installed).
I update the agent to aws/codebuild/standard:5.0 and was able to successfully pause on the breakpoint and connect to the session.
Side quest
Once I connected I was able to investigate the cause of the inability to CD to the folder. I can confirm that Tim's shot in the dark was correct! All the entries were in fact files - no folders.
This QuickStart is the gift that keeps on giving! When/if I get all the issues resolved I'll submit a PR to update the project. Those interested in the cause of the file/folder issue can follow up there.
Side quest update
The strange flattening behaviour was due to creating the zip file on a Windows machine and unzipping it on a unix machine (the build agent uses an Ubuntu image). Just zipped it using 7-Zip and that did the job.