chore: Add basic script to upgrade most helm-charts

.github/ISSUE_TEMPLATE/pre-release-chart-updates.md

@@ -15,6 +15,11 @@ Most of the charts are located in the `stacks/_templated` folder. Additional fol
 `stacks/observability` and `stacks/signal-processing`. It is recommended to search for `releaseName`
 to find all referenced charts.
 
+### Best-effort helper script
+
+There is a best-effort helper script which might help you: `.scripts/update_helm_charts.py`.
+Please read the warnings it prints on startup and keep them in mind.
+
 ### Update Instructions
 
 These instructions help to update the charts:

.scripts/update_helm_charts.py

@@ -0,0 +1,107 @@
+#!/usr/bin/env python
+
+import os
+import subprocess
+import yaml
+from typing import Tuple, Set
+
+def run_helm_repo_add(repo_name: str, repo_url: str) -> None:
+    try:
+        subprocess.run(["helm", "repo", "add", repo_name, repo_url], check=True)
+    except subprocess.CalledProcessError as e:
+        if "already exists" in e.stderr.decode() if e.stderr else str(e):
+            pass  # Ignore "already exists" error
+        else:
+            raise
+
+
+def run_helm_repo_update(repo_name: str) -> None:
+    subprocess.run(["helm", "repo", "update", repo_name], check=True)
+
+
+def get_chart_and_app_version(repo_name: str, chart_name: str) -> Tuple[str, str]:
+    full_chart = f"{repo_name}/{chart_name}"
+    result = subprocess.run(
+        ["helm", "show", "chart", full_chart],
+        capture_output=True,
+        text=True,
+        check=True
+    )
+    chart_yaml = yaml.safe_load(result.stdout)
+    return chart_yaml["version"], chart_yaml["appVersion"]
+
+
+def process_yaml_files(top_dir: str) -> None:
+    seen_repos: Set[str] = set()
+
+    for root, _, files in os.walk(top_dir):
+        for file in files:
+            if not file.endswith(".yaml"):
+                continue
+
+            filepath = os.path.join(root, file)
+
+            try:
+                with open(filepath, "r") as f:
+                    raw_lines = f.readlines()
+
+                try:
+                    first_doc = yaml.safe_load("".join(raw_lines))
+                except yaml.YAMLError as e:
+                    if "expected a single document" in str(e):
+                        continue  # silently skip multi-doc YAMLs
+                    print(f"⚠️ Skipping invalid YAML: {filepath}")
+                    continue
+
+                if not isinstance(first_doc, dict):
+                    continue
+
+                if not (
+                    "releaseName" in first_doc
+                    and "version" in first_doc
+                    and "repo" in first_doc
+                    and "name" in first_doc
+                ):
+                    continue
+
+                repo_info = first_doc["repo"]
+                chart_name = first_doc["name"]
+                repo_name = repo_info.get("name")
+                repo_url = repo_info.get("url")
+
+                if not repo_name or not repo_url:
+                    continue
+
+                if repo_name not in seen_repos:
+                    run_helm_repo_add(repo_name, repo_url)
+                    seen_repos.add(repo_name)
+
+                run_helm_repo_update(repo_name)
+
+                # print(f"📦 Updating {filepath} -> {repo_name}/{chart_name}")
+                new_chart_version, new_app_version = get_chart_and_app_version(repo_name, chart_name)
+
+                updated_lines = []
+                for line in raw_lines:
+                    if line.strip().startswith("version:"):
+                        new_line = f'version: {new_chart_version} # {new_app_version}\n'
+                        updated_lines.append(new_line)
+                    else:
+                        updated_lines.append(line)
+
+                with open(filepath, "w") as f:
+                    f.writelines(updated_lines)
+
+                print(f"✅ Updated {filepath}")
+
+            except Exception as e:
+                print(f"⚠️ Error processing {filepath}: {e}")
+
+if __name__ == "__main__":
+    print('⚠️⚠️⚠️ This script is best-effort! Always check the result using "git diff"! ⚠️⚠️⚠️')
+    print('Notably, it skips invalid YAMLs, which can be the case because we sometimes use templating syntax, even for helm-chart definitions')
+    print('Please judge on the skipped files if they contain a helm-chart and should be manually bumped')
+    print('The script can be improved to handle such files in the future')
+    print()
+
+    process_yaml_files(".")

shell.nix

@@ -2,5 +2,9 @@
 pkgs.mkShell {
   packages = with pkgs; [
     gettext # envsubst
+
+    # Needed by .scripts/update_helm_charts.py
+    python311Packages.pyyaml
+    kubernetes-helm
   ];
 }