# Host asset library with FastAPI: structured data imports ## Summary Deploy a asset library built with FastAPI on Ample using the bulk import staging 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 FastAPI: a CSV staged as an object, row-level validation with per-row errors recorded, and a restart-safe import keyed by import id (imported=2 rejected=1 restart=ok). Not separately tested: your import format, mapping and conflict rules; treat the asset library-specific behavior as your application code. ## Infrastructure requirements - 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 - 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 create` with its credentials passed as encrypted S3_* environment variables - An Ample account token with servers:write, databases:read, buckets:read ## Exact 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` ## 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 bulk import staging: a CSV staged as an object, row-level validation with per-row errors recorded, and a restart-safe import keyed by import id (imported=2 rejected=1 restart=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 --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/bulk-import-staging) from the example; then run your own checks. On failure read `ample logs --kind build` then `--kind runtime`. ``` ample logs --kind build ``` ## Tested examples - **FastAPI pattern fixture** (tests/deploy-canaries/fastapi-patterns): Multi-pattern FastAPI app whose bulk import staging module was checked live; the module is under tests/deploy-canaries/_pattern-modules. ## Success checks - app responds on its public URL (`/` on the live URL, expect ample canary fastapi patterns) - bulk-import-staging self-test (`/p/bulk-import-staging` on the live URL, expect imported=2 rejected=1 restart=ok) ## 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 asset library itself (your import format, mapping and conflict rules) 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 verified. ## 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. ## 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 bulk-import-staging and configuration-secrets. Pattern proof: a CSV staged as an object, row-level validation with per-row errors recorded, and a restart-safe import keyed by import id (imported=2 rejected=1 restart=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) Last verified: 2026-09-21T01:14:18Z ## 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 `current`, required scopes: servers:write, databases:read, buckets:read.