# Host asset library with Spring Boot: file attachments

Deploy an asset library 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 asset library-specific behavior as your application code.

## Representative Queries
- Host asset library with Spring Boot: file attachments
- Where can I host Asset library 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
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.
3. **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 (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 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

## 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 asset library 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.
- 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.
- PutObject and GetObject with path-style addressing are verified; multipart upload, listing, presigned URLs and lifecycle rules are not verified.

## Cost Estimate
- **Monthly Amount:** 10.0 USD  
   - Components  
       - App server (s-1vcpu-1gb): $5.00
       - Managed PostgreSQL database (s-1vcpu-1gb): $5.00
   - 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.

## Example
### Spring Boot pattern fixture  
Multi-pattern Spring Boot app whose browser file uploads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

## Next Actions
- **Browse the catalog index**  
  Method: GET  
  Relative Path: /v1/catalog
- **Search published recipes by intent, stack and constraints**  
  Method: POST  
  Relative Path: /v1/catalog/search  
  Body: {"limit":5,"query":"Host asset library with Spring Boot: file attachments"}

- **Prepare a side-effect-free deployment plan for an authorized project**  
  Method: POST  
  Relative Path: /v1/catalog/plan  
  Body: {"inputs":{},"projectId":"","recipeId":"page:recipes:asset-library:spring-boot:attachments","recipeRevision":"r1"}
- **Read the existing agent authentication setup**  
  Method: GET  
  Relative Path: /mcp/setup
- **Browse Asset library**  
  Method: GET  
  Relative Path: /v1/catalog/nodes/workload%3Aasset-library  
  NodeId: workload:asset-library
- **Browse Spring Boot**  
  Method: GET  
  Relative Path: /v1/catalog/nodes/stack%3Aframework-spring-boot  
  NodeId: stack:framework-spring-boot
- **Browse Browser file uploads**  
  Method: GET  
  Relative Path: /v1/catalog/nodes/pattern%3Abrowser-file-uploads  
  NodeId: pattern:browser-file-uploads
- **Browse Deploy web app**  
  Method: GET  
  Relative Path: /v1/catalog/nodes/intent%3Adeploy-web-app  
  NodeId: intent:deploy-web-app