Charm application

.github/workflows/deploy.yaml

@@ -0,0 +1,63 @@
+# Packs the rock and the charm
+#
+# Only the packing jobs are included for now. The deploy jobs (publish the rock
+# to a registry and `juju deploy`/`refresh` the charm) will be added in a
+# follow-up PR once PS7 resources are provisioned by IS.
+#
+# NOTE: when deploy jobs are added here, gate them to the default branch
+# (e.g. `if: github.ref == 'refs/heads/main'`) so they never run from forks/PRs.
+
+name: Pack
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  pack-rock:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up LXD
+        uses: canonical/setup-lxd@main
+
+      - name: Set up Rockcraft
+        run: sudo snap install rockcraft --classic --channel=latest/stable
+
+      - name: Pack rock
+        run: rockcraft pack -v
+
+      - name: Upload rock artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: products-api-rock
+          path: "*.rock"
+          if-no-files-found: error
+
+  pack-charm:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up LXD
+        uses: canonical/setup-lxd@main
+
+      - name: Set up Charmcraft
+        run: sudo snap install charmcraft --classic --channel=latest/stable
+
+      - name: Pack charm
+        working-directory: charm
+        run: charmcraft pack -v
+
+      - name: Upload charm artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: products-api-charm
+          path: "charm/*.charm"
+          if-no-files-found: error

charm/.gitignore

@@ -0,0 +1,12 @@
+venv/
+build/
+*.charm
+.tox/
+.coverage
+__pycache__/
+*.py[cod]
+.idea
+.vscode/
+
+# Charm libraries are fetched by `charmcraft pack` (flask-framework extension)
+lib/

charm/charmcraft.yaml

@@ -0,0 +1,26 @@
+name: products-api
+
+type: charm
+
+base: ubuntu@24.04
+
+platforms:
+  amd64:
+
+# (Required)
+summary: REST API for Canonical product, deployment and version metadata
+
+# (Required)
+description: |
+  products-api is a Flask REST API that stores and serves Canonical product,
+  deployment, and version metadata, backed by PostgreSQL.
+
+extensions:
+  - flask-framework
+
+# products-api requires a PostgreSQL database; block until it is integrated.
+requires:
+  postgresql:
+    interface: postgresql_client
+    optional: false
+    limit: 1

charm/pyproject.toml

@@ -0,0 +1,41 @@
+# Testing tools configuration
+[tool.coverage.run]
+branch = true
+
+[tool.coverage.report]
+show_missing = true
+
+[tool.pytest.ini_options]
+minversion = "6.0"
+log_cli_level = "INFO"
+
+# Linting tools configuration
+[tool.ruff]
+line-length = 99
+lint.select = ["E", "W", "F", "C", "N", "D", "I001"]
+lint.ignore = [
+    "D105",
+    "D107",
+    "D203",
+    "D204",
+    "D213",
+    "D215",
+    "D400",
+    "D404",
+    "D406",
+    "D407",
+    "D408",
+    "D409",
+    "D413",
+]
+extend-exclude = ["__pycache__", "*.egg_info"]
+lint.per-file-ignores = {"tests/*" = ["D100","D101","D102","D103","D104"]}
+
+[tool.ruff.lint.mccabe]
+max-complexity = 10
+
+[tool.codespell]
+skip = "build,lib,venv,icon.svg,.tox,.git,.mypy_cache,.ruff_cache,.coverage"
+
+[tool.pyright]
+include = ["src/**.py"]

charm/requirements.txt

@@ -0,0 +1,2 @@
+ops ~= 2.17
+paas-charm>=1.0,<2

charm/src/charm.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+# Copyright 2026 atakan.saglam@canonical.com
+# See LICENSE file for licensing details.
+
+"""Flask Charm entrypoint."""
+
+import logging
+import typing
+
+import ops
+
+import paas_charm.flask
+
+logger = logging.getLogger(__name__)
+
+
+class ProductsApiCharm(paas_charm.flask.Charm):
+    """Flask Charm service."""
+
+    def __init__(self, *args: typing.Any) -> None:
+        """Initialize the instance.
+
+        Args:
+            args: passthrough to CharmBase.
+        """
+        super().__init__(*args)
+
+
+if __name__ == "__main__":
+    ops.main(ProductsApiCharm)

charm/tox.ini

@@ -0,0 +1,80 @@
+# Copyright 2026 atakan.saglam@canonical.com
+# See LICENSE file for licensing details.
+
+[tox]
+no_package = True
+skip_missing_interpreters = True
+env_list = format, lint, static
+min_version = 4.0.0
+
+[vars]
+src_path = {tox_root}/src
+;tests_path = {tox_root}/tests
+all_path = {[vars]src_path}
+
+[testenv]
+set_env =
+    PYTHONPATH = {tox_root}/lib:{[vars]src_path}
+    PYTHONBREAKPOINT=pdb.set_trace
+    PY_COLORS=1
+pass_env =
+    PYTHONPATH
+    CHARM_BUILD_DIR
+    MODEL_SETTINGS
+
+[testenv:format]
+description = Apply coding style standards to code
+deps =
+    ruff
+commands =
+    ruff format {[vars]all_path}
+    ruff check --fix {[vars]all_path}
+
+[testenv:lint]
+description = Check code against coding style standards
+deps =
+    ruff
+    codespell
+commands =
+    codespell {tox_root}
+    ruff check {[vars]all_path}
+    ruff format --check --diff {[vars]all_path}
+
+[testenv:unit]
+description = Run unit tests
+deps =
+    pytest
+    coverage[toml]
+    -r {tox_root}/requirements.txt
+commands =
+    coverage run --source={[vars]src_path} \
+                 -m pytest \
+                 --tb native \
+                 -v \
+                 -s \
+                 {posargs} \
+                 {[vars]tests_path}/unit
+    coverage report
+
+[testenv:static]
+description = Run static type checks
+deps =
+    pyright
+    -r {tox_root}/requirements.txt
+commands =
+    pyright {posargs}
+
+[testenv:integration]
+description = Run integration tests
+deps =
+    pytest
+    juju
+    pytest-operator
+    -r {tox_root}/requirements.txt
+commands =
+    pytest -v \
+           -s \
+           --tb native \
+           --log-cli-level=INFO \
+           {posargs} \
+           {[vars]tests_path}/integration

migrate.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+
+set -e
+
+# Database migration hook for the charm (paas-charm) deployment.
+#
+# Under the charm, ./entrypoint is not used: paas-charm launches gunicorn
+# directly and runs this script once, on a single unit, before the web service
+# starts. It is the only place schema migrations happen in that deployment.
+#
+# `flask db upgrade` is idempotent, so it is safe across restarts and multiple
+# units. The DB URL is resolved by webapp.app (DATABASE_URL or the charm's
+# POSTGRESQL_DB_CONNECT_STRING).
+python3 -m flask --app webapp.app db upgrade

migrations/env.py

@@ -1,5 +1,4 @@
 from logging.config import fileConfig
-import os
 import sys
 from sqlalchemy import engine_from_config
 from sqlalchemy import pool
@@ -23,10 +22,13 @@
         # Logging setup is non-critical so we skip it rather than block migrations.
         pass
 
-# Set SQLAlchemy URL from Flask config or environment
-db_url = os.environ.get("DATABASE_URL", app.config.get("SQLALCHEMY_DATABASE_URI"))
+# Resolve the database URL from the Flask app config. webapp/app.py already
+# bridges DATABASE_URL (local/dotrun) and the charm-injected
+# POSTGRESQL_DB_CONNECT_STRING, so we reuse that single source here instead of
+# reading os.environ directly.
+db_url = app.config.get("SQLALCHEMY_DATABASE_URI")
 if not db_url:
-    raise RuntimeError("DATABASE_URL must be set for migrations.")
+    raise RuntimeError("No database URL configured for migrations.")
 config.set_main_option("sqlalchemy.url", db_url)
 
 # add your model's MetaData object here

requirements.txt

@@ -11,5 +11,5 @@ psycopg2-binary>=2.9.9
 SQLAlchemy==2.0.23
 SQLAlchemy-Utils>=0.41.2
 Talisker>=0.16.0
-gunicorn>=20.0.4
+gunicorn[gevent]>=20.0.4
 setuptools

rockcraft.yaml

@@ -0,0 +1,25 @@
+name: products-api
+base: bare
+build-base: ubuntu@24.04
+version: "0.1" # just for humans. Semantic versioning is recommended
+summary: REST API for Canonical product, deployment and version metadata
+description: |
+  products-api is a Flask REST API that stores and serves Canonical product,
+  deployment, and version metadata, backed by PostgreSQL.
+platforms:
+  amd64:
+
+extensions:
+  - flask-framework
+
+parts:
+  flask-framework/install-app:
+    prime:
+      # A Flask prime override fully replaces the default file list. Application
+      # code is under webapp/ (not app/), so it must be listed explicitly, along
+      # with the migration entrypoint and Alembic assets.
+      - flask/app/app.py
+      - flask/app/webapp
+      - flask/app/migrations
+      - flask/app/migrate.sh
+      - flask/app/alembic.ini

webapp/app.py

@@ -9,7 +9,12 @@
 app.json.sort_keys = False
 
 # Database Configuration
-app.config["SQLALCHEMY_DATABASE_URI"] = get_flask_env("DATABASE_URL")
+# When deployed via the 12-factor charm, paas-charm's PostgreSQL integration
+# injects POSTGRESQL_DB_CONNECT_STRING. Fall back to it so the same code runs
+# unchanged under local/dotrun (DATABASE_URL) and the charm runtime.
+app.config["SQLALCHEMY_DATABASE_URI"] = get_flask_env(
+    "DATABASE_URL"
+) or get_flask_env("POSTGRESQL_DB_CONNECT_STRING")
 app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
 
 # API Documentation