# Deliver public assets through CDN for Spring Boot

## Summary

Cdn assets for a Spring Boot app on Ample. Verified on Spring Boot: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. 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.

## Infrastructure requirements

- Compute: verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- CDN: verified (The CDN host serves objects from published buckets. It does not front app compute and is not a cache or key-value store.)

## Prerequisites

- A Spring Boot project (./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 bucket from `ample bucket create` with credentials passed as encrypted S3_* environment variables
- An Ample account token with servers:write, buckets:read

## Exact 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)`

## 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. **Publish a bucket for public assets.** Publish only the asset bucket; upload versioned keys with an immutable Cache-Control header and build URLs from its public URL.

```
   ample bucket publish <bucket-name>
   ```
3. **Verify.** Fetch the live URL and /p/versioned-static-assets on the example; on failure read the build and runtime logs.

```
   ample logs <deployment_id> --kind build
   ```

## Tested examples

- **Spring Boot pattern fixture** (tests/deploy-canaries/spring-boot-patterns): Verified CDN assets on Spring Boot.

## Success checks

- app responds on its public URL (`/` on the live URL, expect ample canary spring boot patterns)
- versioned-static-assets check from the example (`/p/versioned-static-assets` on the live URL, expect see the pattern fixture checks)

## Limitations

- Verified on the jvm-21 template at s-1vcpu-2gb; other sizes and Spring Boot major versions are not verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- The CDN serves published-bucket objects only; cache rules, purge and TTL control are not verified.

## Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1 `s-1vcpu-1gb`: 5.00 USD

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

## Verification evidence

- canary_run on 2026-09-21T02:34:39Z at revision `1d28ae0-dirty (CLI 0.1.21)`: 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); for this guide: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. (expires 2027-03-20T02:34:39Z)

Last verified: 2026-09-21T02:34:39Z

## Execution binding

MCP tool `ample_deploy` (registry `mcp:ample_deploy`), schema hash `876465fce906da0c` observed 2026-09-21T03:19:59.461917+00:00 at revision `49962bcade4f`, binding state `current`, required scopes: servers:write, buckets:read.