Host asset library with ASP.NET Core: file attachments

Overview

Deploy an asset library built with ASP.NET Core on Ample using the browser file uploads 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 ASP.NET Core: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Not separately tested: your upload UI, allowed types, size limits and virus scanning; treat the asset library-specific behavior as your application code.

Representative Queries

• Host asset library with ASP.NET Core: file attachments
• Where can I host Asset library built with ASP.NET Core?
• I need a restricted upload flow, file validation and record-to-object linkage.

Resource Requirements

• primitive:compute
• primitive:postgres
• primitive: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.
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.
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.

Execution Status

• Framework: ASP.NET Core
• Workload: Asset library
• Support Status: verified
• Release Status: published
• Execution Status: ready

Prerequisites

• A ASP.NET Core project that builds and starts with the documented commands (dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT)
• 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

Step 1: Build and Start

• Command: dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT. The server must bind 0.0.0.0 on PORT.

Step 2: Implement the Pattern on PostgreSQL

• The fixture's module implements browser file uploads: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

Step 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.

Step 4: Deploy

• Run command: ample deploy . --name --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...
• Execute synchronously and read the result.

Step 5: Verify

• Fetch the live URL and the pattern self-test route(s) (/p/browser-file-uploads) 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 dotnet-10 template at s-1vcpu-1gb with the example fixture; other sizes, templates and ASP.NET Core major versions are not verified.
• The asset library itself (your upload UI, allowed types, size limits and virus scanning) 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: 10.0
• Components:
  1. App server: s-1vcpu-1gb, Quantity: 1.0, Monthly Amount: 5.0
  2. 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

1. ASP.NET Core pattern fixture deployed on Ample (dotnet publish -c Release -o out in the builder, then dotnet .dll on the dotnet-10 template with ASPNETCORE_URLS bound to PORT); checks passed for browser-file-uploads and configuration-secrets.
2. The same ASP.NET Core app deployed with a --release-command migration; the marker it created was readable after activation.

Next Actions

• Browse the catalog index.
• Search published recipes by intent, stack and constraints.
• Prepare a side-effect-free deployment plan for an authorized project.
• Read the existing agent authentication setup.
• Browse Asset library.
• Browse ASP.NET Core.
• Browse Browser file uploads.
• Browse Deploy web app.