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streamlit-postgres-app/README.md

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+# Streamlit + Lakebase Postgres App
+
+A simple todo list template that demonstrates how to build a Streamlit application backed by an autoscaling Postgres database (Lakebase) hosted on Databricks Apps. Tasks are stored, listed, toggled complete, and deleted — all persisted in Postgres.
+
+## Architecture
+
+```
+Streamlit Frontend (Python)
+    ↓ psycopg connection pool
+Lakebase Postgres (Databricks)
+    ↑ OAuth credentials auto-refreshed via Databricks SDK
+Databricks Apps
+```
+
+The app authenticates to Postgres using short-lived OAuth tokens generated by the Databricks SDK. A custom `psycopg.Connection` subclass (`OAuthConnection`) refreshes the credential on every new connection, and a `ConnectionPool` (min 2, max 10) manages connections. Each user gets their own schema, named `{PGAPPNAME}_schema_{PGUSER}`, containing a `todos` table.
+
+## Setup
+
+Create and activate a virtual environment:
+```bash
+python -m venv .venv
+source .venv/bin/activate
+```
+
+Install Python dependencies:
+```bash
+pip install -r requirements.txt
+```
+
+## Configuration
+
+The app reads its database connection settings from environment variables:
+
+- `PGENDPOINT` - Lakebase Postgres endpoint (injected via the `postgres` app resource)
+- `PGDATABASE` - Database name
+- `PGUSER`     - Database user (also used to namespace the per-user schema)
+- `PGHOST`     - Database host
+- `PGPORT`     - Database port
+- `PGSSLMODE`  - SSL mode (defaults to `require`)
+- `PGAPPNAME`  - Application name (defaults to `my_app`, used to namespace the schema)
+
+When deployed on Databricks Apps, these are populated automatically from the bound Postgres resource. The password is not set directly — it is generated as an OAuth token at connection time.
+
+## Development
+
+Run the Streamlit app locally:
+```bash
+streamlit run app.py
+```
+
+This starts the app at http://localhost:8501. You will need the `PG*` environment variables above pointing at a reachable Lakebase Postgres instance and valid Databricks authentication configured for the SDK.
+
+## Databricks Apps Deployment
+
+Configured for Databricks Apps via `app.yaml`, which runs `streamlit run app.py` and binds the `postgres` resource to the `PGENDPOINT` environment variable.
+
+The `manifest.yaml` declares a Postgres resource spec with `CAN_CONNECT_AND_CREATE` permission so the app can create its own schema and table on first run.
+
+## Features
+
+- Add new todos
+- View todos (most recent first)
+- Toggle todos complete/incomplete (completed tasks are struck through)
+- Delete todos
+- Per-user schema isolation
+- Automatic schema and table initialization on startup