Add release notes script

Appends release notes to an existing Github draft release. Release notes are generated from the merge commits since the last tag.

Author: Karl Ranna

assets/script/release-notes.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+set -e
+# avoid issues with relative paths
+cd "$(dirname "$0")"
+
+if [ -z "$(eval "echo \$GH_TOKEN")" ]; then
+  echo "Missing environment variable GH_TOKEN."
+  exit 1
+fi
+
+GITHUB_API_ENDPOINT="https://api.github.com/repos/lightninglabs/lightning-app/releases"
+CURRENT_TAG=v$(sed -n 's/.*"version": "\(.*\)".*/\1/p' ../../package.json)
+PREVIOUS_TAG=$(git describe --tags --abbrev=0 "$(git rev-list --tags --skip=1 --max-count=1)")
+RELEASE_NOTES="\\n# Release Notes\\n$(git log "${PREVIOUS_TAG}"..HEAD \
+  --merges --pretty='* %b [%h](http://github.com/lightninglabs/lightning-app/commit/%H)\n')"
+
+# get existing release from Github
+RELEASE=$(echo \
+  '{"releases": '"$(curl -H "Content-Type: application/json" \
+  -H "Authorization: token $GH_TOKEN" \
+  $GITHUB_API_ENDPOINT)"'}' \
+  | jq '.releases[] | select(.tag_name == "'"$CURRENT_TAG"'") | {id, name, tag_name, target_commitish, body, draft}')
+
+if [ -z "$RELEASE" ]; then
+  echo "Release not found for tag $CURRENT_TAG."
+  exit 1
+fi
+
+# append release notes to the existing release
+UPDATED_RELEASE_NOTES="$(echo "$RELEASE" | jq -r .body)"$RELEASE_NOTES
+UPDATED_RELEASE=$(echo "$RELEASE" | jq ".body |= \"$UPDATED_RELEASE_NOTES\"")
+UPDATE_API_ENDPOINT=$GITHUB_API_ENDPOINT/$(echo "$RELEASE" | jq -r .id)
+curl \
+  -H "Content-Type: application/json" \
+  -H "Authorization: token $GH_TOKEN" \
+  -X PATCH \
+  -d "$UPDATED_RELEASE" \
+  "$UPDATE_API_ENDPOINT";