Apply Database Schema Changes for Express

Summary

Apply database schema changes for an Express app on Ample with a release command. The command runs against the injected DATABASE_URL before the new release goes live, and the release fails instead of activating if the migration fails.

Representative Queries

• Apply database schema changes for Express
• Where can I host Apply database schema changes built with Express?
• I need a framework-specific schema migration and rollback procedure; no managed migration service is assumed.

Resource Requirements

• Compute
• Postgres

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.

Framework

Express

Workload

Apply database schema changes

Release Status

Published

Support Status

Verified

Execution Status

Ready

Prerequisites

• A migration script that reads process.env.DATABASE_URL and exits non-zero on failure
• A PostgreSQL database (supplied or managed)
• An Ample account token with servers:write and databases:read

Tested Configuration

• Template: node-22
• Runtime: node
• Size: s-1vcpu-1gb
• Install: npm install
• Build: npm run build --if-present
• Start: npm run start

Input Schema

{
  "additionalProperties": false,
  "properties": {
    "env": {
      "description": "Encrypted environment variables as KEY=value; secret values are never stored in ample.toml",
      "items": {"pattern": "^[A-Z][A-Z0-9_]*=.*$", "type": "string"},
      "maxItems": 50,
      "type": "array"
    },
    "name": {
      "description": "App name (lowercase, digits and dashes)",
      "maxLength": 63,
      "minLength": 1,
      "pattern": "^[a-z0-9-]+$",
      "type": "string"
    },
    "path": {
      "description": "Project directory to deploy, or one service name from ample.toml",
      "maxLength": 512,
      "minLength": 1,
      "type": "string"
    },
    "release_command": {
      "description": "One-off command run before the release goes live, for example a migration",
      "maxLength": 512,
      "minLength": 1,
      "type": "string"
    },
    "size": {
      "description": "VM size; omit to let Ample pick a runtime-safe size",
      "enum": ["s-1vcpu-256mb", "s-1vcpu-1gb", "s-1vcpu-2gb", "s-2vcpu-2gb", "s-2vcpu-4gb"],
      "type": "string"
    }
  },
  "required": ["name", "path", "release_command"],
  "type": "object"
}

Workflow Steps

1. Write an Idempotent Migration: Create tables and markers with IF NOT EXISTS or a migration tool so a re-run is safe.
2. Deploy with the Release Command: Ample runs the command before activation; a non-zero exit fails the release.

   ample deploy . --name  --public --release-command "node migrate.js"
   

3. Verify the Marker through the App: Serve a route that reads something only the migration creates.
4. Verify: Fetch the live URL and run the success checks below. On failure read the build log, then the runtime log, fix the cause and deploy again; do not blind-retry.

   ample logs  --kind build
   

Examples

• Release-command Migration Canary: node migrate.js creates a marker table before activation; /migrated reads it.

Success Checks

• Migration marker is readable
  • Type: HTTP GET
  • Path: /migrated
  • Expect: migrated=release-ok

Limitations

• Verified on the node-22 template at s-1vcpu-1gb; other templates and sizes are not verified by this recipe.
• 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 managed databases are placed together; cross-node shared databases are unsupported.
• The release command runs once per release on the app VM; there is no separate migration runner or rollback of a partially applied migration.

Cost Estimate

• Currency: USD
• Monthly Amount: 10.0
• Authoritative: true
• Basis: Size prices from pricing.toml (loaded by the API) at build revision.
• Components:
  • App Server: size: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0
  • Managed PostgreSQL Database: size: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0
• Note: Apps and managed databases auto-pause when idle; the estimate is the always-on monthly price of the tested sizes. Plan quotas and budgets apply.

Evidence Summary

• Kind: Canary Run
  • Summary: A --release-command migration ran before the release went live; /migrated reported the marker the migration created.
  • Observed At: 2026-09-19T23:55:33Z
  • Implementation Revision: 1764076-tls-account-903d345
  • Expires At: 2027-03-18T23:55:33Z
  • Scope: {"cliVersion":"0.1.20", "platform":"hosted-beta", "template":"node-22"}

Last Verified At

2026-09-19T23:55:33Z

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