Host form collection with Spring Boot: relational workflow state

Summary

Deploy a form collection built with Spring Boot on Ample using the transactional workflows 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 Spring Boot: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Not separately tested: your domain records, validation rules and concurrency policy; treat the form collection-specific behavior as your application code.

Infrastructure requirements

• Compute: verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
• Postgres: verified (Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.)

Prerequisites

• A Spring Boot project that builds and starts with the documented commands (./mvnw -q -DskipTests package (or the Gradle wrapper) producing one application jar, then java -jar on the jvm-21 template (Temurin JDK 21) with server.port read from PORT)
• 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

Exact tested configuration

• template: jvm-21
• runtime: java
• size: s-1vcpu-2gb
• build: ./mvnw -q -DskipTests package
• start: java -jar $(ls target/*.jar | grep -v -- '-plain' | head -n 1)

Steps

1. Build and start. ./mvnw -q -DskipTests package (or the Gradle wrapper) producing one application jar, then java -jar on the jvm-21 template (Temurin JDK 21) with server.port read from PORT. The server must bind 0.0.0.0 on PORT.
2. Implement the pattern on PostgreSQL. The fixture's module implements transactional workflows: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). 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).

   ample deploy . --name <app-name> --public
   

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

   ample logs <deployment_id> --kind build
   

Tested examples

• Spring Boot pattern fixture: Multi-pattern Spring Boot app whose transactional workflows module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

Success checks

• app responds on its public URL (/ on the live URL, expect ample canary spring boot patterns)
• transactional-workflows self-test (/p/transactional-workflows on the live URL, expect tx=ok history=2 conflict=rejected)

Limitations

• Verified on the jvm-21 template at s-1vcpu-2gb with the example fixture; other sizes, templates and Spring Boot major versions are not verified.
• The form collection itself (your domain records, validation rules and concurrency 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

Estimated 10.00 USD per month.

• app server x1 s-1vcpu-1gb: 5.00 USD
• managed PostgreSQL database x1 s-1vcpu-1gb: 5.00 USD

Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

Verification evidence

• canary_run on 2026-09-21T02:34:39Z: Spring Boot pattern fixture deployed on Ample; checks passed for transactional-workflows and configuration-secrets.

Execution binding

MCP tool ample_deploy, schema hash 876465fce906da0c observed 2026-09-21T03:19:59 at revision 49962bcade4f, binding state current, required scopes: servers:write, databases:read.