chore: add script to generate release notes

Signed-off-by: Josh <josh.t.richards@gmail.com>

.github/scripts/generate-release-draft.sh

@@ -0,0 +1,208 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+: "${GH_TOKEN:?GH_TOKEN is required}"
+: "${REPO:?REPO is required}"
+
+official_repo="docker-library/official-images"
+tmp_notes="${RUNNER_TEMP}/release-notes.md"
+
+export SKIP_RELEASE=false
+export SKIP_REASON=""
+export OFFICIAL_IMAGES_PR=""
+export OFFICIAL_IMAGES_PR_URL=""
+export PREVIOUS_TAG=""
+export RELEASE_TAG=""
+export TARGET_SHA=""
+
+if [[ -n "${INPUT_OFFICIAL_IMAGES_PR:-}" ]]; then
+  OFFICIAL_IMAGES_PR="${INPUT_OFFICIAL_IMAGES_PR}"
+else
+  OFFICIAL_IMAGES_PR="$(
+    gh pr list \
+      --repo "$official_repo" \
+      --search 'is:merged label:"library/nextcloud"' \
+      --state merged \
+      --limit 20 \
+      --json number,mergedAt \
+      --jq 'sort_by(.mergedAt) | reverse | .[0].number'
+  )"
+fi
+
+if [[ -z "$OFFICIAL_IMAGES_PR" || "$OFFICIAL_IMAGES_PR" == "null" ]]; then
+  SKIP_RELEASE=true
+  SKIP_REASON="No merged docker-library/official-images pull request with label library/nextcloud was found."
+  {
+    echo "SKIP_RELEASE=true"
+    echo "SKIP_REASON=$SKIP_REASON"
+  } >> "$GITHUB_ENV"
+  exit 0
+fi
+
+official_pr_json="$(
+  gh pr view "$OFFICIAL_IMAGES_PR" \
+    --repo "$official_repo" \
+    --json number,title,mergedAt,url,labels,author
+)"
+
+OFFICIAL_IMAGES_PR_URL="$(jq -r '.url' <<<"$official_pr_json")"
+official_pr_merged_at="$(jq -r '.mergedAt' <<<"$official_pr_json")"
+
+existing_tags="$(
+  gh release list \
+    --repo "$REPO" \
+    --limit 100 \
+    --json tagName \
+    --jq '.[].tagName'
+)"
+
+if [[ -n "$existing_tags" ]]; then
+  while read -r tag; do
+    [[ -z "$tag" ]] && continue
+    description="$(
+      gh release view "$tag" \
+        --repo "$REPO" \
+        --json description \
+        --jq '.description // ""'
+    )"
+    if grep -q "docker-library/official-images/pull/${OFFICIAL_IMAGES_PR}" <<<"$description"; then
+      SKIP_RELEASE=true
+      SKIP_REASON="A release already references docker-library/official-images PR #${OFFICIAL_IMAGES_PR}."
+      {
+        echo "SKIP_RELEASE=true"
+        echo "SKIP_REASON=$SKIP_REASON"
+      } >> "$GITHUB_ENV"
+      exit 0
+    fi
+  done <<< "$existing_tags"
+fi
+
+PREVIOUS_TAG="$(
+  gh release list \
+    --repo "$REPO" \
+    --exclude-drafts \
+    --limit 20 \
+    --json tagName,publishedAt \
+    --jq 'sort_by(.publishedAt) | reverse | .[0].tagName'
+)"
+
+if [[ -z "$PREVIOUS_TAG" || "$PREVIOUS_TAG" == "null" ]]; then
+  echo "Could not determine the previous published release tag." >&2
+  exit 1
+fi
+
+previous_release_json="$(
+  gh release view "$PREVIOUS_TAG" \
+    --repo "$REPO" \
+    --json tagName,publishedAt,targetCommitish
+)"
+
+previous_published_at="$(jq -r '.publishedAt' <<<"$previous_release_json")"
+
+if [[ -n "${INPUT_RELEASE_TAG:-}" ]]; then
+  RELEASE_TAG="${INPUT_RELEASE_TAG}"
+else
+  year_month="$(date -u +v%Y.%m)"
+  existing_month_tags="$(
+    gh release list \
+      --repo "$REPO" \
+      --limit 100 \
+      --json tagName \
+      --jq '.[].tagName' \
+      | grep "^${year_month}\." || true
+  )"
+
+  next_n=1
+  if [[ -n "$existing_month_tags" ]]; then
+    max_n="$(
+      sed -n "s/^${year_month}\.\([0-9][0-9]*\)$/\1/p" <<<"$existing_month_tags" \
+      | sort -n \
+      | tail -1
+    )"
+    if [[ -n "$max_n" ]]; then
+      next_n=$((max_n + 1))
+    fi
+  fi
+
+  RELEASE_TAG="${year_month}.${next_n}"
+fi
+
+TARGET_SHA="$(git rev-parse origin/master)"
+
+repo_prs_json="$(
+  gh pr list \
+    --repo "$REPO" \
+    --search "is:merged merged:>${previous_published_at}" \
+    --state merged \
+    --limit 100 \
+    --json number,title,url,author,mergedAt
+)"
+
+change_count="$(jq 'length' <<<"$repo_prs_json")"
+
+{
+  echo "## What's Changed"
+  echo
+
+  if [[ "$change_count" -eq 0 ]]; then
+    echo "* No merged pull requests were found since ${PREVIOUS_TAG}"
+  else
+    jq -r '.[] | "* \(.title) by @\(.author.login) in \(.url)"' <<<"$repo_prs_json"
+  fi
+
+  echo
+  echo "## New Contributors"
+  echo
+
+  first_time_contributors="$(
+    jq -r '.[].author.login' <<<"$repo_prs_json" | sort -u | while read -r login; do
+      [[ -z "$login" ]] && continue
+      count="$(
+        gh pr list \
+          --repo "$REPO" \
+          --search "is:merged author:${login}" \
+          --state merged \
+          --limit 100 \
+          --json number \
+          --jq 'length'
+      )"
+      if [[ "$count" -eq 1 ]]; then
+        echo "$login"
+      fi
+    done
+  )"
+
+  if [[ -z "$first_time_contributors" ]]; then
+    echo "* No new contributors in this release"
+  else
+    while read -r login; do
+      [[ -z "$login" ]] && continue
+      echo "* @${login} made their first contribution"
+    done <<<"$first_time_contributors"
+  fi
+
+  echo
+  echo "**Full Changelog**:"
+  echo "* Image: https://github.com/${REPO}/compare/${PREVIOUS_TAG}...master"
+  echo "* Nextcloud Server: https://nextcloud.com/changelog/"
+  echo "* Docker Official Image: ${OFFICIAL_IMAGES_PR_URL}"
+  echo
+  echo "<!-- release-meta:"
+  echo "official_images_pr=${OFFICIAL_IMAGES_PR}"
+  echo "official_images_merged_at=${official_pr_merged_at}"
+  echo "previous_tag=${PREVIOUS_TAG}"
+  echo "target_sha=${TARGET_SHA}"
+  echo "generated_at=$(date -u +%FT%TZ)"
+  echo "-->"
+} > "$tmp_notes"
+
+{
+  echo "SKIP_RELEASE=false"
+  echo "OFFICIAL_IMAGES_PR=$OFFICIAL_IMAGES_PR"
+  echo "OFFICIAL_IMAGES_PR_URL=$OFFICIAL_IMAGES_PR_URL"
+  echo "PREVIOUS_TAG=$PREVIOUS_TAG"
+  echo "RELEASE_TAG=$RELEASE_TAG"
+  echo "TARGET_SHA=$TARGET_SHA"
+} >> "$GITHUB_ENV"
+
+echo "Prepared release draft notes at $tmp_notes"