page:recipes:project tracker:flask:csv imports
Host project tracker with Flask: CSV imports
Deploy a project tracker built with Flask 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 Flask: 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 project tracker-specific behavior as your application code.
Representative Queries
- Host project tracker with Flask: CSV imports
- Where can I host Project tracker built with Flask?
- I need a domain CSV format, row validation, deduplication and an import recovery path.
Resource Requirements
- primitive:compute
- primitive:postgres
- primitive: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.
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 createwith its credentials passed as encrypted S3_* environment variables - An Ample account token with servers:write, databases:read, buckets:read
Workflow Steps
- 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.
- 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.
- 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.
- 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" --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=... - 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 buildthen--kind runtime.ample logs --kind build
Examples
- Flask pattern fixture: Multi-pattern Flask 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.
- Kind:
http_get - Path:
/ - Expect:
ample canary flask patterns
- Kind:
- Bulk-import-staging self-test.
- Kind:
http_get - Path:
/p/bulk-import-staging - Expect:
imported=2 rejected=1 restart=ok
- Kind:
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 project tracker 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.
Cost Estimate
- Currency: USD
- Monthly Amount: 10.0
- Authoritative: true
- Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
- Components:
- App server: s-1vcpu-1gb - $5.00
- Managed PostgreSQL database: s-1vcpu-1gb - $5.00
- 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
- Canary run: Flask pattern fixture deployed on Ample; checks passed for bulk-import-staging and configuration-secrets.
- Canary run: The same Flask app deployed with a --release-command migration; the marker it created was readable after activation.