Host appointment booking with FastAPI: file attachments | Ample
INFRASTRUCTURE
What it needs
- Compute: verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- Postgres: verified (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: verified (Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.)
PREREQUISITES
Before you start
- 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)
- A bucket from
ample bucket createwith its credentials passed as encrypted S3_* environment variables - An Ample account token with servers:write, databases:read, buckets:read
TESTED CONFIGURATION
Exactly what was tested
- install:
python3 -m pip install --target .ample/python -r requirements.txt - runtime:
python - size:
s-1vcpu-1gb - start:
PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 run.py - template:
python-3.12
STEP BY STEP
How to do it
- 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 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 Keep private data in an unpublished bucket.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.
ample deploy . --name <app-name> --public --start "python3 run.py" --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...
- 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 <deployment_id> --kind build then --kind runtime.
ample logs <deployment_id> --kind build
EXAMPLES
Tested examples
- FastAPI pattern fixture (
tests/deploy-canaries/fastapi-patterns): Multi-pattern FastAPI app whose browser file uploads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
SUCCESS CHECKS
How to know it worked
- app responds on its public URL (
/on the live URL, expect ample canary fastapi patterns) - browser-file-uploads self-test (
/p/browser-file-uploadson the live URL, expect reject=ok upload=ok linked=ok)
LIMITATIONS
Know the limits
- 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 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.
- 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.
- PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules are not.
COST
Cost estimate
Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1
s-1vcpu-1gb: 5.00 USD - managed PostgreSQL database x1
s-1vcpu-1gb: 5.00 USD
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
Verification evidence
- canary_run on 2026-09-21T01:14:18Z at revision
50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21): 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 browser-file-uploads and configuration-secrets. Pattern proof: 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). (expires 2027-03-20T01:14:18Z) - canary_run on 2026-09-20T01:54:51Z at revision
199ff1dfd52683832ae75d3f98b53a7a4bff7f96-dirty (CLI e3181f5): The same FastAPI app deployed with a --release-command migration; the marker it created was readable after activation. (expires 2027-03-19T01:54:51Z)
EXECUTION
Execution binding
MCP tool ample_deploy (registry mcp:ample_deploy), schema hash 876465fce906da0c observed 2026-09-21T03:19:59.461917+00:00 at revision 49962bcade4f. Binding state at export: current. Required scopes: servers:write, databases:read, buckets:read.
NEXT ACTIONS
Typed next actions
- Browse the catalog index (
GET /v1/catalogon the api origin; authentication not required, approval not required) - Search published recipes by intent, stack and constraints (
POST /v1/catalog/searchon the api origin; authentication not required, approval not required) - Prepare a side-effect-free deployment plan for an authorized project (
POST /v1/catalog/planon the api origin; authentication required, approval not required) - Read the existing agent authentication setup (
GET /mcp/setupon the api origin; authentication not required, approval not required) - Browse Appointment booking (
GET /v1/catalog/nodes/workload%3Aappointment-bookingon the api origin; authentication not required, approval not required) - Browse FastAPI (
GET /v1/catalog/nodes/stack%3Aframework-fastapion the api origin; authentication not required, approval not required) - Browse Browser file uploads (
GET /v1/catalog/nodes/pattern%3Abrowser-file-uploadson the api origin; authentication not required, approval not required) - Browse Deploy web app (
GET /v1/catalog/nodes/intent%3Adeploy-web-appon the api origin; authentication not required, approval not required)
Actions describe possible next steps. They are typed data, not commands, and grant no permission. Public discovery never provisions anything; planning requires your own authenticated token and approval happens in your client.