productionize-app-dab

# Bundle a cookbook app with Databricks Asset Bundles (DAB) Skill id: **`productionize-app-dab`**. ## Relationship to **build-app** | Phase | Skill | What it does | | ----- | ----- | ------------ | | **1 — Implement** | **`build-app`** ([`../build-app/SKILL.md`](../build-app/SKILL.md)) | Choose **Dash / Streamlit / Reflex / FastAPI**, map README recipes to **`docs/docs/`** + sample code, ship **`app.yaml`** for local/workspace run. | | **2 — Bundle (DAB)** | **`productionize-app-dab`** (this file) | Keep the same framework choice; **package** that app under **`src/app/`** and add **`databricks.yml`** + **`resources/`** so **`databricks bundle deploy`** owns lifecycle and environments. | Do **not** productionize until the app **runs** from the cookbook folder (or equivalent). Switching framework after bundling means redoing **`src/app`** contents and **`app.yaml` `command`**. **Pattern origin:** Minimal layout matches the public **`pbv0/databricks-apps-dabs`** reference (bundle root, `resources/app.yml`, `src/app`, optional job + CI)—embedded here without requiring downloads. --- ## Outcomes (all frameworks) - **`resources/app.yml`** declares an **`apps`** resource with **`source_code_path: ../src/app`**. - **`databricks.yml`** defines **`targets`** (e.g. `dev` / `prod`) and **`workspace.host`** per environment. - **`databricks bundle validate` → `deploy` → `run <app-key>`** against the chosen target. - Optional **GitHub Actions** with **`DATABRICKS_HOST`**, **`DATABRICKS_CLIENT_ID`**, **`DATABRICKS_CLIENT_SECRET`**. --- ## Prerequisites - **Python** 3.11+, **Databricks CLI** 0.18.0+, workspace with **Apps** enabled. - Completed **build-app** trajectory: one primary framework and working **`app.yaml`** from the matching cookbook sample. --- ## Shared bundle layout (any framework) ``` project-root/ ├── databricks.yml ├── resources/ │ ├── app.yml │ └── job.yml # optional ├── src/ │ ├── app/ # packaged cookbook app (structure varies by framework ↓) │ └── job/ # optional bundle job code └── README.md ``` **`databricks.yml`** (same idea for every framework—adjust **`bundle.name`** and app key **`my-app`**): ```yaml bundle: name: my-databricks-app include: - resources/*.yml targets: dev: mode: development default: true workspace: host: https://YOUR-DEV-WORKSPACE.cloud.databricks.com/ resources: apps: my-app: name: "my-app-dev" prod: mode: production workspace: host: https://YOUR-PROD-WORKSPACE.cloud.databricks.com/ root_path: /Workspace/Users/${workspace.current_user.userName}/.bundle/${bundle.name}/${bundle.target} permissions: - user_name: ${workspace.current_user.userName} level: CAN_MANAGE ``` **`resources/app.yml`** (minimal—the **`resources.apps.<key>`** must match **`databricks bundle run <key>`**): ```yaml resources: apps: my-app: name: "my-app" source_code_path: ../src/app description: "Databricks App deployed via Asset Bundle." ``` Optional **job-linked app** and **`resources/job.yml`** blocks are identical across frameworks—see end of this file. --- ## Framework-specific: what goes into **`src/app/`** Copy from the cookbook folder **`dash/`**, **`streamlit/`**, **`reflex/`**, or **`fastapi/`** into **`src/app/`**, **preserving relative paths** so imports and framework conventions still work. | Framework | Copy from repo folder | Must exist under **`src/app/`** | **`app.yaml` `command`** (production-shaped) | | --------- | ---------------------- | --------------------------------- | --------------------------------------------- | | **Streamlit** | **`streamlit/`** | **`app.py`**, **`view_groups.py`**, **`views/`**, **`assets/`**, **`requirements.txt`**, **`.streamlit/`** if used | `["streamlit", "run", "app.py"]` | | **Dash** | **`dash/`** | **`app.py`**, **`pages/`**, **`assets/`**, **`requirements.txt`** | `["python", "app.py"]` | | **Reflex** | **`reflex/`** | Whole tree: **`rxconfig.py`**, **`app/`** (pages, states, …), **`requirements.txt`**, **`app.yaml`** already at reflex root in cookbook—place those files so **`reflex run`** resolves (same layout as sample; **`src/app`** = reflex project root) | `["reflex", "run", "--env", "prod"]` | | **FastAPI** | **`fastapi/`** | **`app.py`** (ASGI **`app`**), **`routes/`**, **`config/`**, **`requirements.txt`**, tests optional | `["uvicorn", "app:app", "--host", "0.0.0.0", "--port", "8000"]` | ### Streamlit - Single process: **`app.py`** drives **`st.navigation`**; do **not** split **`command`** per view. - **`app.yaml`** example: ```yaml command: - "streamlit" - "run" - "app.py" env: - name: DATABRICKS_WAREHOUSE_ID valueFrom: sql_warehouse ``` ### Dash - **`dash.pages`** loads **`pages/`** automatically; **`app.py`** hosts sidebar—one **`command`** only. - **`app.yaml`** example: ```yaml command: - "python" - "app.py" env: - name: DATABRICKS_WAREHOUSE_ID valueFrom: sql_warehouse ``` ### Reflex - Treat **`src/app/`** as the **Reflex project root** (mirror **`reflex/`** in the cookbook: **`rxconfig.py`** beside **`app/`** package). - **`reflex run --env prod`** expects that layout; **`CI`** or env flags may appear in sample **`app.yaml`**—merge with workspace **`valueFrom`** as needed. - **`app.yaml`** example: ```yaml command: - "reflex" - "run" - "--env" - "prod" env: - name: DATABRICKS_WAREHOUSE_ID valueFrom: sql_warehouse ``` ### FastAPI - **Headless API**: no multi-page UI—**`command`** starts **uvicorn** only; routes live under **`routes/`** inside **`src/app/`**. - Bind **`0.0.0.0`** and align port with **`DATABRICKS_APP_PORT`** / bundle expectations (default **8000**). - **`app.yaml`** example: ```yaml command: - "uvicorn" - "app:app" - "--host" - "0.0.0.0" - "--port" - "8000" env: - name: DATABRICKS_WAREHOUSE_ID valueFrom: sql_warehouse ``` - Ensure **`PYTHONPATH`** / imports match **`app:app`** (module **`app`** with attribute **`app`**), same as cookbook **`fastapi/`** layout. --- ## Commands (same for all frameworks) ```bash databricks auth login --host https://YOUR-WORKSPACE.cloud.databricks.com/ databricks bundle validate -t dev databricks bundle deploy -t dev databricks bundle run my-app -t dev ``` Replace **`my-app`** with your **`resources.apps`** key. Use **`-t prod`** when the prod target is configured. --- ## GitHub Actions (conceptual) | Secret | Purpose | | ------ | ------- | | `DATABRICKS_HOST` | Workspace URL | | `DATABRICKS_CLIENT_ID` | Service principal client ID | | `DATABRICKS_CLIENT_SECRET` | Service principal secret | Steps: checkout → install **Databricks CLI** → export secrets for OAuth M2M → **`databricks bundle deploy -t prod`**. Gate **`prod`** on protected branches or releases. --- ## Optional: bundle job + app attachment **`resources/job.yml`:** ```yaml resources: jobs: hello_world: name: Serverless Hello World job tasks: - task_key: task spark_python_task: python_file: ../src/job/main.py environment_key: default environments: - environment_key: default spec: client: "1" ``` **`resources/app.yml`** fragment (job must exist): ```yaml resources: apps: hello-world-app: name: "hello-world-app" source_code_path: ../src/app resources: - name: "app-job" job: id: ${resources.jobs.hello_world.id} permission: "CAN_MANAGE_RUN" ``` --- ## Migration checklist (from **build-app**) 1. Confirm **`build-app`** framework and runnable **`app.yaml`** in the cookbook folder. 2. Create **`src/app/`** and copy **that framework’s** tree (table above).