# Host AI Workflow Runner with Express: Stored Input and Output Artifacts

Deploy an AI workflow runner built with Express on Ample using the generated downloads 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 Express: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Not separately tested: your export formats, retention policy and entitlement model; treat the AI workflow runner-specific behavior as your application code.

## Representative Queries
- Host AI workflow runner with Express: stored input and output artifacts
- Where can I host AI workflow runner built with Express?
- I need an input/output artifact contract, object metadata and access boundaries.

## Resource Requirements
- Compute
- PostgreSQL
- S3-compatible object storage

## Infrastructure Requirements
1. **Compute**  
   Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.  
   **Status:** Verified  
   **Canonical Path:** /discover/primitive/compute

2. **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.  
   **Status:** Verified  
   **Canonical Path:** /discover/primitive/postgres

3. **S3-compatible object storage**  
   Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.  
   **Status:** Verified  
   **Canonical Path:** /discover/primitive/s3-compatible-object-storage

## Prerequisites
- A Express project that builds and starts with the documented commands (npm install, npm run build --if-present, npm run start on the node-22 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

## Workflow Steps
1. **Build and Start**  
   npm install, npm run build --if-present, npm run start on the node-22 template. The server must bind 0.0.0.0 on PORT.

2. **Implement the Pattern on PostgreSQL**  
   The fixture's module implements generated downloads: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). 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.  
   Command: `ample deploy . --name --public --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/generated-downloads) from the example; then run your own checks. On failure, read `ample logs --kind build` then `--kind runtime`.  
   Command: `ample logs --kind build`

## Limitations
- Verified on the node-22 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Express major versions are not verified.
- The AI workflow runner itself (your export formats, retention policy and entitlement model) 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 Estimate
- **Currency:** USD  
- **Monthly Amount:** $10.00  
- **Basis:** Size prices from pricing.toml (loaded by the API) at build revision.
  - 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
- Express pattern fixture deployed on Ample (npm install, npm run build --if-present, npm run start on the node-22 template); checks passed for generated-downloads and configuration-secrets. Pattern proof: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3).

## Formats
- [HTML](/content/recipes/ai-workflow-runner/express/artifact-storage/index.html)  
- [Markdown](/content/recipes/ai-workflow-runner/express/artifact-storage.md)  
- [JSON](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Aai-workflow-runner%3Aexpress%3Aartifact-storage)

## Next Actions
- **Browse the catalog index**  
   GET /v1/catalog
- **Search published recipes by intent, stack and constraints**  
   POST /v1/catalog/search  
   Body: {"limit":5,"query":"Host ai workflow runner with Express: stored input and output artifacts"}
- **Prepare a side-effect-free deployment plan for an authorized project**  
   POST /v1/catalog/plan  
   Body: {"inputs":{},"projectId":"","recipeId":"page:recipes:ai-workflow-runner:express:artifact-storage","recipeRevision":"r1"}
- **Read the existing agent authentication setup**  
   GET /mcp/setup  
- **Browse AI workflow runner**  
   GET /v1/catalog/nodes/workload%3Aai-workflow-runner  
- **Browse Express**  
   GET /v1/catalog/nodes/stack%3Aframework-express  
- **Browse Generated downloads**  
   GET /v1/catalog/nodes/pattern%3Agenerated-downloads  
- **Browse Deploy AI app**  
   GET /v1/catalog/nodes/intent%3Adeploy-ai-app