## The short version

Deploy an event registration 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.

## WHAT WAS VERIFIED

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).

## INFRASTRUCTURE

### What it needs

- [Compute](/content/discover/primitive/compute/index.html): verified (Apps run in isolated x86_64 Firecracker microVMs; sizes are the priced VM sizes.)
- [Postgres](/content/discover/primitive/postgres/index.html): verified (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](/content/discover/primitive/s3-compatible-object-storage/index.html): verified (Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.)

## PREREQUISITES

### Before you start

- 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

## STEP BY STEP

### How to do it

1. 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. 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. 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. 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.

```
ample deploy . --name <app-name> --public --env S3_ENDPOINT=... --env S3_REGION=... --env S3_BUCKET=... --env S3_ACCESS_KEY_ID=... --env S3_SECRET_ACCESS_KEY=...
```

5. 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 <deployment_id> --kind build` then `--kind runtime`.

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

## EXAMPLES

### Tested examples

- **Spring Boot pattern fixture** (`tests/deploy-canaries/spring-boot-patterns`): Multi-pattern Spring Boot app whose browser file uploads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

## SUCCESS CHECKS

### How to know it worked

- app responds on its public URL (`/` on the live URL, expect ample canary spring boot patterns)
- browser-file-uploads self-test (`/p/browser-file-uploads` on the live URL, expect reject=ok upload=ok linked=ok)

## COST

### Cost estimate

Estimated 10.00 USD per month (size prices from pricing.toml at build revision ca0b484a7a9957c573a88d3a32dc603c3c10135a).

- app server x1 `s-1vcpu-1gb`: 5.00 USD
- managed PostgreSQL database x1 `s-1vcpu-1gb`: 5.00 USD

Upper-bound monthly price of the tested sizes. Buckets are allocation-priced per quota and not included.

## EVIDENCE

### Verification evidence

- canary_run on 2026-09-21T02:34:39Z at revision `1d28ae0 (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); checks passed for browser-file-uploads and configuration-secrets. Pattern proof: 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). (expires 2027-03-20T02:34:39Z)
- canary_run on 2026-09-20T22:49:19Z at revision `af6f45adea26 (CLI af6f45a)`: The same Spring Boot app deployed with a --release-command migration; the marker it created was readable after activation. (expires 2027-03-19T22:49:19Z)

## EXECUTION

### Execution binding

MCP tool `ample_deploy` (registry `mcp:ample_deploy`), schema hash `876465fce906da0c` observed 2026-09-22T00:31:22.774679+00:00 at revision `e6446ceea69b`. Binding state at export: schema_changed. Required scopes: servers:write, databases:read, buckets:read.

## NEXT ACTIONS

### Typed next actions

- Browse the catalog index (`GET /v1/catalog` on the api origin; authentication not required, approval not required)
- Search published recipes by intent, stack and constraints (`POST /v1/catalog/search` on the api origin; authentication not required, approval not required)
- Prepare a side-effect-free deployment plan for an authorized project (`POST /v1/catalog/plan` on the api origin; authentication required, approval not required)
- Read the existing agent authentication setup (`GET /mcp/setup` on the api origin; authentication not required, approval not required)
- Browse Event registration (`GET /v1/catalog/nodes/workload%3Aevent-registration` on the api origin; authentication not required, approval not required)
- Browse Spring Boot (`GET /v1/catalog/nodes/stack%3Aframework-spring-boot` on the api origin; authentication not required, approval not required)
- Browse Browser file uploads (`GET /v1/catalog/nodes/pattern%3Abrowser-file-uploads` on the api origin; authentication not required, approval not required)
- Browse Deploy web app (`GET /v1/catalog/nodes/intent%3Adeploy-web-app` on the api origin; authentication not required, approval not required)

Actions describe possible next steps. They are typed data, not commands, and grant no permission. Public discovery never provisions anything; planning requires your own authenticated token and approval happens in your client.

## ABOUT THIS RECIPE

### Identifiers and status

Recipe `page:recipes:event-registration:spring-boot:attachments`. Revision r1.

release **published**support **verified**execution **blocked (schema_changed: live tool schema differs from the recorded binding)**

Formats: [HTML](/content/recipes/event-registration/spring-boot/attachments/index.html) | [Markdown](/content/recipes/event-registration/spring-boot/attachments.md) | [JSON contract](https://api.ample.computer/v1/catalog/recipes/page%3Arecipes%3Aevent-registration%3Aspring-boot%3Aattachments)