Host form collection with Spring Boot: file attachments

Deploy a form collection 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 form collection-specific behavior as your application code.

Representative Queries

• Host form collection with Spring Boot: file attachments
• Where can I host Form collection 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
   Verified: 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
   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.
3. S3-compatible object storage
   Verified: 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.
• 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 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). 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

Examples

1. 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.

Success Checks

1. App responds on its public URL

   • Kind: http_get
   • Path: /
   • Expect: ample canary spring boot patterns

2. Browser-file-uploads self-test

   • Kind: http_get
   • Path: /p/browser-file-uploads
   • Expect: reject=ok upload=ok linked=ok

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 form collection itself 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.
• PutObject and GetObject with path-style addressing are verified; other S3 operations are not verified.