Initial code drop.

hooks/pre_build

@@ -0,0 +1,38 @@
+#!/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."