page:recipes:ai chat application:axum:artifact storage

Host ai chat application with Axum: stored input and output artifacts

Summary

Deploy a AI chat application built with Axum 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 Axum: 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 chat application-specific behavior as your application code.

Representative Queries

• Host AI chat application with Axum: stored input and output artifacts
• Where can I host AI chat application built with Axum?
• I need an input/output artifact contract, object metadata and access boundaries.

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

• An Axum project that builds and starts with the documented commands (cargo build --release in the rust builder image (stable toolchain, Cargo.lock committed, pure-Rust dependencies), then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL).
• 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
   cargo build --release in the rust builder image, then the release binary on the ubuntu-24.04 template reading PORT and DATABASE_URL. 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.
   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); then run your own checks. On failure read ample logs --kind build then --kind runtime.
   ample logs --kind build

Examples

• Axum pattern fixture
  Multi-pattern Axum app whose generated downloads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

Success Checks

• app responds on its public URL: HTTP Get to / expecting ample canary axum patterns
• generated-downloads self-test: HTTP Get to /p/generated-downloads expecting export=ok rows=3 (with ?token=...; 401 without)

Limitations

• Verified on the ubuntu-24.04 template at s-1vcpu-2gb with the example fixture; other sizes, templates and Axum major versions are not verified.
• The AI chat application 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 verified.

Cost Estimate

• Monthly Cost: $10.00 USD
  Components:
  • App server: size s-1vcpu-1gb, quantity: 1.0, monthly amount: $5.00
  • Managed PostgreSQL database: size s-1vcpu-1gb, quantity: 1.0, monthly amount: $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: Axum pattern fixture deployed on Ample; checks passed for generated-downloads and configuration-secrets.
  • Observed At: 2026-09-21T02:46:37Z
  • Expires At: 2027-03-20T02:46:37Z
  • Implementation Revision: 1d28ae0-dirty (CLI 0.1.21)

Formats

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