## 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.

### Representative Queries
- Host form collection with Spring Boot: relational workflow state
- Where can I host Form collection built with Spring Boot?
- I need a domain record schema, validation rules and concurrency behavior.

### Resource Requirements
- **primitive:compute**
- **primitive: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.

### Prerequisites
1. 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.
2. A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env).
3. An Ample account token with servers:write, databases:read.

### 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)

### Workflow 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). Re-running with no change is a no-op. Command: ample deploy . --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  --kind build` then `--kind runtime`. Command: ample logs  --kind build.

### Success Checks
- App responds on its public URL
- Transactional-workflows self-test

### Limitations
1. 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.
2. 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.

### Example
- **Title**: Spring Boot pattern fixture
  - **Description**: Multi-pattern Spring Boot app whose transactional workflows module was checked live; the module is under tests/deploy-canaries/_pattern-modules.
  - **Source Reference**: tests/deploy-canaries/spring-boot-patterns.

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: size prices from pricing.toml (loaded by the API)
- **Components**:
  - App server: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0
  - Managed PostgreSQL database: s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0

### 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 Form collection
- Browse Spring Boot
- Browse Transactional workflows
- Browse Deploy web app