### Host csv import tool with Flask: relational workflow state

Deploy a csv import tool built with Flask on Ample using the transactional workflows 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. Verified on Flask: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Not separately tested: your domain records, validation rules and concurrency policy; treat the csv import tool-specific behavior as your application code.

#### Representative Queries
- Host csv import tool with Flask: relational workflow state
- Where can I host CSV import tool built with Flask?
- I need a domain record schema, validation rules and concurrency behavior.

#### Resource Requirements
- Compute
- PostgreSQL

#### 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.

#### Framework
Flask

#### Workload
CSV import tool

#### Release Status
Published

#### Support Status
Verified

#### 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)
- An Ample account token with servers:write, databases: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`

#### 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 transactional workflows: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **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. `ample deploy . --name  --public --start "python3 app.py"`
4. **Verify**: Fetch the live URL and the pattern self-test route(s) (/p/transactional-workflows) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`. `ample logs  --kind build`

#### 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 csv import tool itself (your domain records, validation rules and concurrency policy) is application code and was not separately tested; the pattern checks are what was verified.

#### Cost Estimate
- **Currency**: USD  
- **Monthly Amount**: 10.0  
- **Components**:  
  - **app server**:  size s-1vcpu-1gb, quantity 1.0, monthlyAmount 5.0  
  - **managed PostgreSQL database**: size s-1vcpu-1gb, quantity 1.0, monthlyAmount 5.0  
  - **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
- The Flask pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then waitress from app.py reading PORT on the python-3.12 template); checks passed for transactional-workflows and configuration-secrets. Pattern proof: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected).

#### Next Actions
- Browse the catalog index
- Search published recipes by intent, stack and constraints
- Prepare a side-effect-free deployment plan for an authorized project
- Read the existing agent authentication setup
- Browse CSV import tool
- Browse Flask
- Browse Transactional workflows
- Browse Deploy web app