Variable mysteriously disappears? AWS CodeBuild - bash

Question

What follows is my buildspec.yml
build:
commands:
- 'IMAGE_TAG=$(cat package.json | grep version | head -1 | awk -F: ''{ print $2 }'' | sed ''s/[",]//g'')'
- echo $IMAGE_TAG
- docker build -t $IMAGE_REPO_NAME:$IMAGE_TAG .
- docker tag $IMAGE_REPO_NAME:$IMAGE_TAG $AWS_ACCOUNT_ID.dkr.ecr.$AWS_DEFAULT_REGION.amazonaws.com/$IMAGE_REPO_NAME:$IMAGE_TAG
Here's the output from the relevant build:
[Container] 2018/12/12 22:06:42 Running command IMAGE_TAG=$(cat package.json | grep version | head -1 | awk -F: '{ print $2 }' | sed 's/[",]//g')
[Container] 2018/12/12 22:06:42 Running command echo $IMAGE_TAG <<< GOOD
1.0.0 <<<< PERFECT
[Container] 2018/12/12 22:06:42 Running command docker build -t $IMAGE_REPO_NAME:$IMAGE_TAG .
invalid argument "gotbot-air:" for t: invalid reference format
See 'docker build --help'. <<<<<< OH NO
[Container] 2018/12/12 22:06:42 Command did not exit successfully docker build -t $IMAGE_REPO_NAME:$IMAGE_TAG . exit status 125
As you can clearly see on the marked lines, somehow the variable $IMAGE_TAG is set correctly to 1.0.0 when echo'd, yet on the very next line of execution in my build script, it seems to have disappeared.
Please note I am using version 0.2 of the specification.
EDIT: It may be important that my other environment variables are either declared at the top in env or native code build variables, it might be that im getting some different execution environment when running the docker command?

Answer 1

Check the version of your BuildSpec file. Change it to version: 0.2.
In version 0.1, AWS CodeBuild runs each build command in a separate instance of the default shell in the build environment. In version 0.2, AWS CodeBuild runs all build commands in the same instance of the default shell in the build environment.