page:recipes:ai chat application:echo:persistent state

Host AI Chat Application with Echo: Postgres-backed State

Summary
Deploy an AI chat application built with Echo on Ample using the durable job state 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. Verified on Echo: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Not separately tested: your job types, payload schema and retry policy; treat the AI chat application-specific behavior as your application code.

Representative Queries

• Host AI chat application with Echo: Postgres-backed state
• Where can I host an AI chat application built with Echo?
• I need a durable state schema and retry/recovery semantics implemented by application code.

Workflow Steps

1. Build and start
   CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build). The server must bind 0.0.0.0 on PORT.
2. Implement the pattern on PostgreSQL
   The fixture's module implements durable job state: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. 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
   

4. Verify
   Fetch the live URL and the pattern self-test route(s) (/p/durable-job-state) from the example; then run your own checks. On failure read ample logs --kind build then --kind runtime.

   ample logs  --kind build
   

Prerequisites

• A Echo project that builds and starts with the documented commands (CGO_ENABLED=0 go build -o app ./... then ./app on the ubuntu-24.04 template (go.sum committed for a reproducible build))
• A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
• An Ample account token with servers:write, databases:read

Success Checks

• App responds on its public URL
  • Kind: http_get
  • Path: /
  • Expect: ample canary echo patterns
• Durable-job-state self-test
  • Kind: http_get
  • Path: /p/durable-job-state
  • Expect: job=done attempts=1 idempotent=true

Limitations

• Verified on the ubuntu-24.04 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Echo major versions are not verified.
• The AI chat application itself (your job types, payload schema and retry 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.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.0
• Note: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.

Evidence Summary

• Kind: canary_run
  • Summary: Echo pattern fixture deployed on Ample; checks passed for durable-job-state and configuration-secrets.
  • Observed At: 2026-09-21T02:34:39Z
  • Scope: checks=[/p/durable-job-state]

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