Example script to generate CI variables for a build process

set_ci_variables.sh

#!/bin/sh
set -Eeou pipefail

# args
MAIN_BRANCH=${MAIN_BRANCH:-main}
BUILD_NUMBER=${BUILD_NUMBER:-0}

docker_tag_parse_string() {
  KEY=$(echo $1 | awk '{print tolower($0)}')
  re='(.*)[^a-z0-9.-]+(.*)'
  while [[ $KEY =~ $re ]]; do
    KEY=${BASH_REMATCH[1]}-${BASH_REMATCH[2]}
  done
  echo $KEY
}

# set variables
BRANCH=$(git branch | sed -n -e 's/^\* \(.*\)/\1/p')
COMMIT_HASH=$(git rev-parse HEAD)
GENERATED_AT="`date -u +%Y-%m-%dT%H:%M:%SZ`";

if [ "$BRANCH" = "$MAIN_BRANCH" ]; then
  VERSION="`date -u +%Y%m%d`-$BUILD_NUMBER";
else
  VERSION=$(docker_tag_parse_string $BRANCH)
fi

# writing to file so Bamboo can read it
echo "VERSION=$VERSION
BRANCH=$BRANCH
BUILD_NUMBER=$BUILD_NUMBER
GENERATED_AT=$GENERATED_AT
COMMIT_HASH=$COMMIT_HASH"