# Host appointment booking with Flask: file attachments

Deploy a appointment booking built with Flask on Ample using the browser file uploads pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on Flask: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Not separately tested: your upload UI, allowed types, size limits and virus scanning; treat the appointment booking-specific behavior as your application code.

## Representative Queries
- Host appointment booking with Flask: file attachments
- Where can I host Appointment booking built with Flask?
- I need a restricted upload flow, file validation and record-to-object linkage.

## Resource Requirements
- Compute
- Postgres
- S3-compatible object storage

## Infrastructure Requirements
### Compute
- Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
### Postgres
- Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
### S3-compatible object storage
- Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

## Framework
Flask

## Workload
Appointment booking

## Release Status
Published

## Execution Status
Ready

## Prerequisites
- A Flask project that builds and starts with the documented commands (pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template)
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
- A bucket from `ample bucket create` with its credentials passed as encrypted S3_* environment variables
- An Ample account token with servers:write, databases:read, buckets:read

## Tested Configuration
- Template: python-3.12
- Runtime: python
- Size: s-1vcpu-1gb
- Install: python3 -m pip install --target .ample/python -r requirements.txt
- Start: PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 app.py

## Input Schema
- **Properties**:
  - **env**: Encrypted environment variables (bucket credentials, secrets)
  - **name**: App name
  - **path**: Project directory or ample.toml service
  - **release_command**: Migration command run before activation
  - **start**: Start command (Python apps pass one explicitly)
- **Required**: env, name, path, start

## Workflow Steps
1. **Build and start**: pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template. The server must bind 0.0.0.0 on PORT.
2. **Implement the pattern on PostgreSQL**: The fixture's module implements browser file uploads: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Wire object storage**: Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
4. **Deploy**: Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.
5. **Verify**: Fetch the live URL and the pattern self-test route(s) (/p/browser-file-uploads) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.

## Examples
- **Title**: Flask pattern fixture
- **Description**: Multi-pattern Flask app whose browser file uploads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
- **Source Ref**: tests/deploy-canaries/flask-patterns

## Success Checks
- **App responds on its public URL**: Expect "ample canary flask patterns"
- **Browser file uploads self-test**: Expect "reject=ok upload=ok linked=ok"

## Limitations
- Verified on the python-3.12 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Flask major versions are not verified.
- The appointment booking itself (your upload UI, allowed types, size limits and virus scanning) is application code and was not separately tested; the pattern checks are what was verified.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: Size prices from pricing.toml at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty.
- **Components**:
  - App server: s-1vcpu-1gb
  - Managed PostgreSQL database: s-1vcpu-1gb
- **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

## Evidence Summary
- **Kind**: canary_run
  **Summary**: Flask pattern fixture deployed on Ample; checks passed for browser-file-uploads and configuration-secrets.

## Last Verified At
2026-09-21T01:14:18Z

## Formats
- [HTML Format](/content/recipes/appointment-booking/flask/attachments/index.html)
- [Markdown Format](/content/recipes/appointment-booking/flask/attachments.md)
- [JSON Format](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Aappointment-booking%3Aflask%3Aattachments)