### Host appointment booking with Spring Boot: file attachments

Deploy a appointment booking built with Spring Boot on Ample using the browser file uploads 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, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on Spring Boot: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Not separately tested: your upload UI, allowed types, size limits and virus scanning; treat the appointment booking-specific behavior as your application code.

#### Representative Queries
- Host appointment booking with Spring Boot: file attachments
- Where can I host Appointment booking built with Spring Boot?
- I need a restricted upload flow, file validation and record-to-object linkage.

#### Resource Requirements
- **primitive:compute**
- **primitive:postgres**
- **primitive:s3-compatible-object-storage**

#### 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.
- **S3-compatible object storage**: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

#### Prerequisites
- A Spring Boot project that builds and starts with the documented commands (`./mvnw -q -DskipTests package`) 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).
- A bucket from `ample bucket create` with its credentials passed as encrypted S3_* environment variables.
- An Ample account token with servers:write, databases:read, buckets: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 browser file uploads: content-type and size validation that rejects disallowed files, an object written to a private bucket and a row linking the record to the object key (reject=ok upload=ok linked=ok). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Wire object storage**: Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
4. **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 --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...`
5. **Verify**: Fetch the live URL and the pattern self-test route(s) (`/p/browser-file-uploads`) 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 (`/`)
- browser-file-uploads self-test (`/p/browser-file-uploads`)

#### 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 upload UI, allowed types, size limits and virus scanning) is application code and was not separately tested; the pattern checks are what was verified.