## Host community forum with Spring Boot: application activity history

### Summary  
Deploy a community forum 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 community forum-specific behavior as your application code.

### Representative Queries  
- Host community forum with Spring Boot: application activity history  
- Where can I host Community forum built with Spring Boot?  
- I need an application-owned event schema and tested history queries; not native platform audit logs.

### Resource Requirements  
- **Compute**  
- **Postgres**

### Infrastructure Requirements  
- **Compute**  
  - Status: verified  
  - Summary: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.  
- **Postgres**  
  - Status: verified  
  - Summary: 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

### 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`

### Examples  
- **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

### Success Checks  
- App responds on its public URL.  
  - Kind: http_get  
  - Path: /  
  - Expect: ample canary spring boot patterns
- Transactional-workflows self-test.  
  - Kind: http_get  
  - Path: /p/transactional-workflows  
  - 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 community forum 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  
- Authoritative: true  
- Basis: size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty  
- Components:  
  - App server: 1x s-1vcpu-1gb at $5.0  
  - Managed PostgreSQL database: 1x s-1vcpu-1gb at $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.

### Evidence Summary  
- **Canary Run**  
  - Summary: Spring Boot pattern fixture deployed on Ample (./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); checks passed for transactional-workflows and configuration-secrets. Pattern proof: 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).
  - Observed At: 2026-09-21T02:34:39Z  
  - Implementation Revision: 1d28ae0-dirty (CLI 0.1.21)  
  - Expires At: 2027-03-20T02:34:39Z
- **Canary Run**  
  - Summary: The same Spring Boot app deployed with a --release-command migration; the marker it created was readable after activation.
  - Observed At: 2026-09-20T22:49:19Z  
  - Implementation Revision: af6f45adea26-dirty (CLI af6f45a)  
  - Expires At: 2027-03-19T22:49:19Z

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