Host CSV Import Tool with FastAPI: Relational Workflow State

Summary

Deploy a CSV import tool built with FastAPI 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 FastAPI: 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 FastAPI: relational workflow state
• Where can I host CSV import tool built with FastAPI?
• I need a domain record schema, validation rules, and concurrency behavior.

Resource Requirements

• primitive: compute
• primitive: postgres

Infrastructure Requirements

1. Compute

   • Status: Verified
   • Summary: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.

2. Postgres

   • Status: Verified
   • Summary: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

Prerequisites

• A FastAPI project that builds and starts with the documented commands (pip install into .ample/python from requirements.txt, then uvicorn from run.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 run.py

Workflow Steps

1. Build and Start

   • pip install into .ample/python from requirements.txt, then uvicorn from run.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.
   • Command: ample deploy . --name --public --start "python3 run.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.
   • Command: ample logs --kind build

Examples

• FastAPI Pattern Fixture
  Multi-pattern FastAPI app whose transactional workflows module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
  • Source Ref: tests/deploy-canaries/fastapi-patterns

Success Checks

1. The app responds on its public URL.

   • Kind: http_get
   • Path: /
   • Expect: ample canary fastapi patterns

2. Transactional-workflows self-test.

   • Kind: http_get
   • Path: /p/transactional-workflows
   • Expect: tx=ok history=2 conflict=rejected

Limitations

• Verified on the python-3.12 template at s-1vcpu-1gb with the example fixture; other sizes, templates, and FastAPI 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.
• Region, compliance attestations, and request-duration limits are unknown and not claimed.
• Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
• Managed PostgreSQL 16 only; extensions, connection limits, and backup or restore procedures are not verified; apps and their databases are placed together.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.0
• Components:
  • App server: s-1vcpu-1gb, quantity: 1.0, monthlyAmount: 5.0
  • Managed PostgreSQL database: 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.

Evidence Summary

1. Canary Run
   Summary: FastAPI pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template); checks passed for transactional-workflows and configuration-secrets.

   • Observed At: 2026-09-21T01:14:18Z
   • Scope:
     • Checks: [/p/transactional-workflows]
     • Pattern: pattern:transactional-workflows
     • Template: python-3.12

2. Canary Run
   Summary: The same FastAPI app deployed with a --release-command migration; the marker it created was readable after activation.

   • Observed At: 2026-09-20T01:54:51Z
   • Scope:
     • Pattern: pattern:transactional-workflows

Last Verified At

• Date: 2026-09-21T01:14:18Z

Unknowns

• Region availability is unknown until a verified region fact is recorded.
• Compliance attestations are unknown; none are claimed.

Formats

• HTML
• Markdown
• JSON

Next Actions

1. Browse the Catalog Index

   • Operation: GET /v1/catalog

2. Search Published Recipes by Intent, Stack, and Constraints

   • Operation: POST /v1/catalog/search
   • Parameters: { "limit": 5, "query": "Host csv import tool with FastAPI: relational workflow state" }

3. Prepare a Side-Effect-Free Deployment Plan for an Authorized Project

   • Operation: POST /v1/catalog/plan
   • Parameters: { "inputs": {}, "projectId": "", "recipeId": "page:recipes:csv-import-tool:fastapi:relational-workflow", "recipeRevision": "r1" }

4. Read the Existing Agent Authentication Setup

   • Operation: GET /mcp/setup

5. Browse CSV Import Tool

   • Operation: GET /v1/catalog/nodes/workload%3Acsv-import-tool

6. Browse FastAPI

   • Operation: GET /v1/catalog/nodes/stack%3Aframework-fastapi

7. Browse Transactional Workflows

   • Operation: GET /v1/catalog/nodes/pattern%3Atransactional-workflows

8. Browse Deploy Web App

   • Operation: GET /v1/catalog/nodes/intent%3Adeploy-web-app