## Host appointment booking with Spring Boot: relational workflow state

### Summary
Deploy an appointment booking 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 appointment booking-specific behavior as your application code.

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

### Resource Requirements
- Compute
- PostgreSQL

### Infrastructure Requirements
1. **Compute**  
   Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
2. **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
Spring Boot

### Workload
Appointment booking

### Release Status
Published

### Support Status
Verified

### Execution Status
Ready

### 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

### 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`

### 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)`

### 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 appointment booking 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
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Basis**: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty

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

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