django.md
Home services: inventory manager using Django
Summary
A inventory manager blueprint for home services built with Django on Ample. Domain schema: services (sku, name, category, price_from, duration_estimate): service catalog as SKUs; parts_stock (sku, delta, reason, moved_at): parts and consumables movements; jobs (job_no, service_area, status, scheduled_for): jobs as orders with status transitions; job_lines (job_no, sku, qty): services and parts on a job; events (seq, record_type, record_id, kind, at): application-owned history written in the same transaction. Public information: service catalog and pricing from, service areas and hours, licensing and insurance summary. Kept out of scope until handling is reviewed: customer addresses and access notes, payment details. Customer addresses and access instructions are personal data; keep them out until handling is reviewed. Technical basis verified on Django: 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).
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 Django project (pip install into .ample/python from requirements.txt, then waitress serving project.wsgi from run.py reading PORT on the python-3.12 template)
- A PostgreSQL driver reading DATABASE_URL (auto-provisioned when omitted)
- Bucket credentials from
ample bucket createpassed as encrypted S3_* environment variables - A review of which home services data classes may be handled at all; this blueprint models public information only
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
Model the home services domain. Create the tables services, parts_stock, jobs, job_lines, events. Service catalog as skus lives in services; keep the sensitive classes (customer addresses and access notes, payment details) out of this schema.
Workflow step 1. Model SKUs and stock movements; derive stock from movements
Workflow step 2. Apply movements transactionally with an optimistic version check on the SKU
Workflow step 3. Record an event per movement for history
Workflow step 4. Deploy and verify history and rejected stale updates
Deploy. Run the synchronous deploy once and read the result. 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=...Verify. Run the pattern self-test(s) from the example (/p/transactional-workflows) and your own acceptance checks for the home services workflow.
ample logs <deployment_id> --kind build
Tested examples
- Django pattern fixture (tests/deploy-canaries/django-patterns): Verified transactional workflows basis for this blueprint.
Success checks
- App responds on its public URL (
/on the live URL, expect ample canary django patterns) - Transactional-workflows self-test from the example (
/p/transactional-workflowson the live URL, expect see the pattern fixture checks)
Limitations
- The technical basis (transactional workflows on Django) was verified with the pattern fixture; the home services schema and workflow are an original design for this blueprint and were not executed as a separate application.
- No health, financial, privacy or other compliance claim is made. Customer addresses and access instructions are personal data; keep them out until handling is reviewed.
- Public content and synthetic examples only until actual data-handling requirements have been reviewed.
- Verified on the python-3.12 template at s-1vcpu-1gb; region, request-duration limits and other sizes are unknown or unverified.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified.
- PutObject and GetObject with path-style addressing are verified; other S3 operations and CDN cache rules are not.
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 2026-09-20T03:31:44Z at revision
03b6402b1b3e19178985f08ea4033804521d85d4-dirty (CLI b75e104): Django pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then waitress serving project.wsgi from run.py reading PORT on the python-3.12 template); the transactional workflows checks passed: 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). The blueprint's Home services schema and workflow below build on that verified basis and were not separately executed. (expires 2027-03-19T03:31:44Z)
Last verified: 2026-09-20T03:31:44Z
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.