Host ai chat application with Spring Boot: stored input and output artifacts | Ample
INFRASTRUCTURE
What it needs
- 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.)
- 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.)
- 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
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 createwith its credentials passed as encrypted S3_* environment variables - An Ample account token with servers:write, databases:read, buckets:read
TESTED CONFIGURATION
Exactly what was tested
- build:
./mvnw -q -DskipTests package - runtime:
java - size:
s-1vcpu-2gb - start:
java -jar $(ls target/*.jar | grep -v -- '-plain' | head -n 1) - template:
jvm-21
STEP BY STEP
How to do it
- 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 Keep private data in an unpublished bucket.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.
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
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 <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 generated downloads 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) - generated-downloads self-test (
/p/generated-downloadson the live URL, expect export=ok rows=3 (with ?token=...; 401 without))
LIMITATIONS
Know the limits
- 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 ai chat application itself (your export formats, retention policy and entitlement model) 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.
COST
Cost estimate
Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1
s-1vcpu-1gb: 5.00 USD - managed PostgreSQL database x1
s-1vcpu-1gb: 5.00 USD
Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.
EVIDENCE
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); checks passed for generated-downloads and configuration-secrets. Pattern proof: 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). (expires 2027-03-20T02:34:39Z) - canary_run on 2026-09-20T22:49:19Z at revision
af6f45adea26-dirty (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 2026-09-21T03:19:59.461917+00:00 at revision 49962bcade4f. Binding state at export: current. Required scopes: servers:write, databases:read, buckets:read.
NEXT ACTIONS
Typed next actions
- Browse the catalog index (
GET /v1/catalogon the api origin; authentication not required, approval not required) - Search published recipes by intent, stack and constraints (
POST /v1/catalog/searchon the api origin; authentication not required, approval not required) - Prepare a side-effect-free deployment plan for an authorized project (
POST /v1/catalog/planon the api origin; authentication required, approval not required) - Read the existing agent authentication setup (
GET /mcp/setupon the api origin; authentication not required, approval not required) - Browse AI chat application (
GET /v1/catalog/nodes/workload%3Aai-chat-applicationon the api origin; authentication not required, approval not required) - Browse Spring Boot (
GET /v1/catalog/nodes/stack%3Aframework-spring-booton the api origin; authentication not required, approval not required) - Browse Generated downloads (
GET /v1/catalog/nodes/pattern%3Agenerated-downloadson the api origin; authentication not required, approval not required) - Browse Deploy AI app (
GET /v1/catalog/nodes/intent%3Adeploy-ai-appon 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.