# Host blog with Flask: object-stored public media

## Summary
Deploy a blog built with Flask on Ample using the public media library 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, and a published bucket serves public assets from the CDN host. Verified on Flask: an object written to a published bucket with an immutable Cache-Control header, a mapping row, and the CDN URL serving it publicly. Not separately tested: your media processing, object layout and cache policy; treat the blog-specific behavior as your application code.

## Representative Queries
- Host blog with Flask: object-stored public media
- Where can I host Blog built with Flask?
- I need an object layout, public asset URL policy and CDN delivery configuration.

## Resource Requirements
- primitive:compute
- primitive:postgres
- primitive:s3-compatible-object-storage
- primitive:cdn

## 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 create` with its credentials passed as encrypted S3_* environment variables and a second, published bucket for public assets (CDN_*)
- An Ample account token with servers:write, databases:read, buckets: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 app.py

## Workflow Steps
1. **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.
2. **Implement the pattern on PostgreSQL**  
The fixture's module implements public media library: an object written to a published bucket with an immutable Cache-Control header, a mapping row, and the CDN URL serving it publicly. 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. Publish only the bucket that serves public assets and reference its CDN URL.
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 app.py" --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=... --env CDN_PUBLIC_URL=...`
5. **Verify**  
Fetch the live URL and the pattern self-test route(s) (/p/public-media-library) from the example; then run your own checks. On failure read `ample logs --kind build` then `--kind runtime`.  
`ample logs --kind build`

## Success Checks
- **App responds on its public URL**  
  - **Kind:** http_get  
  - **Path:** /  
  - **Expect:** ample canary flask patterns
- **Public-media-library self-test**  
  - **Kind:** http_get  
  - **Path:** /p/public-media-library  
  - **Expect:** a CDN URL whose content is served publicly

## 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 blog itself (your media processing, object layout and cache 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.
- PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules are not.
- The CDN serves published-bucket objects only; cache rules, purge and TTL control are not verified (the fixture sets Cache-Control on upload and versions keys).

## Cost Estimate
- **Currency:** USD  
- **Monthly Amount:** 10.0  
- **Components:**  
  - **App server:** s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0  
  - **Managed PostgreSQL database:** s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0  
- **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 public-media-library and configuration-secrets. Pattern proof: an object written to a published bucket with an immutable Cache-Control header, a mapping row, and the CDN URL serving it publicly.  
- **Canary run:** The same Flask app deployed with a --release-command migration; the marker it created was readable after activation.

## Next Actions
- **Browse the catalog index**  
  - **Method:** GET  
  - **Relative Path:** /v1/catalog  
- **Search published recipes by intent, stack and constraints**  
  - **Method:** POST  
  - **Relative Path:** /v1/catalog/search  
  - **Parameters:** {"body":{"limit":5,"query":"Host blog with Flask: object-stored public media"}}  
- **Prepare a side-effect-free deployment plan for an authorized project**  
  - **Method:** POST  
  - **Relative Path:** /v1/catalog/plan  
  - **Parameters:** {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:blog:flask:public-media","recipeRevision":"r1"}}  
- **Read the existing agent authentication setup**  
  - **Method:** GET  
  - **Relative Path:** /mcp/setup  
- **Browse Blog**  
  - **Method:** GET  
  - **Relative Path:** /v1/catalog/nodes/workload%3Ablog  
- **Browse Flask**  
  - **Method:** GET  
  - **Relative Path:** /v1/catalog/nodes/stack%3Aframework-flask  
- **Browse Public media library**  
  - **Method:** GET  
  - **Relative Path:** /v1/catalog/nodes/pattern%3Apublic-media-library  
- **Browse Deploy web app**  
  - **Method:** GET  
  - **Relative Path:** /v1/catalog/nodes/intent%3Adeploy-web-app