#!/bin/bash
#
# Pre build hook for Docker Automated Build.
#
# This hooks modifies the Dockerfile by inserting the image version in the
# related label.
#

set -e # Exit immediately if a command exits with a non-zero status.
set -u # Treat unset variables as an error.

# Make sure the DOCKER_TAG has a supported format like:
#     v1.0.0
#     v0.1.0-beta1
#     v2.0.0-rc2
if [[ ! "$DOCKER_TAG" =~ ^v[0-9\.]+(-(alpha|beta|rc)[0-9]+)?$ ]]; then
  echo "Unsupported DOCKER_TAG: $DOCKER_TAG"
  exit 1
fi

# The version to use is the same has the DOCKER_TAG, minus the initial 'v'.
IMAGE_VERSION="${DOCKER_TAG:1}"

# Export our custom variables.
echo "IMAGE_VERSION=\"$IMAGE_VERSION\"" >> custom_hook_env

echo "Environment variables:
    IMAGE_NAME=$IMAGE_NAME
    DOCKER_REPO=$DOCKER_REPO
    DOCKER_TAG=$DOCKER_TAG
    SOURCE_BRANCH=$SOURCE_BRANCH
    IMAGE_VERSION=$IMAGE_VERSION
"

echo "Inserting image version in Dockerfile..."
sed -i "s/org.label-schema.version=\"unknown\"/org.label-schema.version=\"$IMAGE_VERSION\"/" Dockerfile

echo "pre_build hook terminated successfully."