## Host Approval Workflow with Spring Boot: Downloadable Reports

Deploy an approval workflow built with Spring Boot on Ample using the generated downloads 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: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Not separately tested: your export formats, retention policy and entitlement model; treat the approval workflow-specific behavior as your application code.

### Representative Queries
- Host approval workflow with Spring Boot: downloadable reports
- Where can I host Approval workflow built with Spring Boot?
- I need an export query, generated artifact retention and authorized download flow.

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

### Infrastructure Requirements
1. **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.

2. **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.

3. **S3-compatible Object Storage**  
   - **Status:** verified  
   - **Summary:** 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` 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`)
- 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 generated downloads: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). 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/generated-downloads`) 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.
- Generated-downloads self-test.

### 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 approval workflow itself (your export formats, retention policy and entitlement model) is application code and was not separately tested; the pattern checks are what was verified.

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

### Examples
- **Spring Boot Pattern Fixture**  
   Multi-pattern Spring Boot app whose generated downloads module was checked live; the module is under `tests/deploy-canaries/_pattern-modules.`