add renovate config to repos

add-renovate.sh

#!/usr/bin/env bash
set -euo pipefail

if [[ $# -lt 1 ]]; then
    echo "Usage: $0 <owner/repo> [owner/repo ...]"
    exit 1
fi

RENOVATE_CONTENT='{
  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
  "extends": [
    "github>grafana/grafana-renovate-config//presets/k6/k6-engine-base.json"
  ]
}
'

BRANCH_NAME="add-renovate-config"
COMMIT_MESSAGE="chore: add renovate config"
PR_TITLE="chore: add renovate config"
PR_BODY="Adds \`renovate.json\` extending the [k6-engine-base preset](https://github.com/grafana/grafana-renovate-config/blob/main/presets/k6/k6-engine-base.json)."

for REPO in "$@"; do
    echo "==> Processing $REPO"

    # Get default branch
    DEFAULT_BRANCH=$(gh api "repos/$REPO" --jq '.default_branch')
    echo "    Default branch: $DEFAULT_BRANCH"

    # Check if renovate.json already exists on default branch
    if gh api "repos/$REPO/contents/renovate.json" --silent 2>/dev/null; then
        echo "    renovate.json already exists, skipping."
        continue
    fi

    echo "    renovate.json not found, creating branch '$BRANCH_NAME'..."

    # Bail out if the branch already exists rather than touching it
    if gh api "repos/$REPO/git/ref/heads/$BRANCH_NAME" --silent 2>/dev/null; then
        echo "    Branch '$BRANCH_NAME' already exists — skipping to avoid overwriting existing work."
        continue
    fi

    # Get SHA of default branch tip
    BASE_SHA=$(gh api "repos/$REPO/git/ref/heads/$DEFAULT_BRANCH" --jq '.object.sha')

    # Create branch
    gh api --method POST "repos/$REPO/git/refs" \
        --field "ref=refs/heads/$BRANCH_NAME" \
        --field "sha=$BASE_SHA" \
        --silent

    # Encode content as base64
    ENCODED=$(printf '%s' "$RENOVATE_CONTENT" | base64 -w 0)

    # Create the file on the new branch
    gh api --method PUT "repos/$REPO/contents/renovate.json" \
        --field "message=$COMMIT_MESSAGE" \
        --field "content=$ENCODED" \
        --field "branch=$BRANCH_NAME" \
        --silent

    echo "    File committed. Opening PR..."

    PR_URL=$(gh pr create \
        --repo "$REPO" \
        --base "$DEFAULT_BRANCH" \
        --head "$BRANCH_NAME" \
        --title "$PR_TITLE" \
        --body "$PR_BODY")

    echo "    PR created: $PR_URL"
done