feat: generate habitat artifact version from git tag

Author: themightychris

habitat/plan.sh

@@ -1,6 +1,5 @@
 pkg_origin="codeforphilly"
 pkg_name="chime"
-pkg_version="0.1.0"
 pkg_maintainer="Code for Philly <[email protected]>"
 pkg_license=('MIT')
 pkg_deps=(
@@ -17,6 +16,39 @@ pkg_bin_dirs=(
 )
 pkg_svc_user="root"
 
+pkg_version() {
+  if [ -n "${pkg_last_tag}" ]; then
+    if [ ${pkg_last_tag_distance} -eq 0 ]; then
+      echo "${pkg_last_version}"
+    else
+      echo "${pkg_last_version}-git+${pkg_last_tag_distance}.${pkg_commit}"
+    fi
+  else
+    echo "${pkg_last_version}-git.${pkg_commit}"
+  fi
+}
+
+do_before() {
+  do_default_before
+
+  # configure git repository
+  export GIT_DIR="${PLAN_CONTEXT}/../.git"
+
+  # load version information from git
+  pkg_commit="$(git rev-parse --short HEAD)"
+  pkg_last_tag="$(git describe --tags --abbrev=0 ${pkg_commit} || true 2>/dev/null)"
+
+  if [ -n "${pkg_last_tag}" ]; then
+    pkg_last_version=${pkg_last_tag#v}
+    pkg_last_tag_distance="$(git rev-list ${pkg_last_tag}..${pkg_commit} --count)"
+  else
+    pkg_last_version="0.0.0"
+  fi
+
+  # initialize pkg_version
+  update_pkg_version
+}
+
 do_prepare() {
   python -m venv "${pkg_prefix}"
   source "${pkg_prefix}/bin/activate"