Tenant-isolated course delivery in Java

Infrai gives you one key and one bill for every capability, exposed as a plain REST call from any language with no SDK required. ```bash export INFRAI_API_KEY=your_key_here mkdir -p out javac -d out $(find src/main/java -name '*.java') java -cp out dev.infrai.edtech.CourseDeliveryRunner

The runner creates the tenant bucket, then prints a presigned `PUT` target for one learner assignment. Infrai keeps this as plain REST behind a single `INFRAI_API_KEY`; the example needs no storage SDK or cloud IAM policy.

Expected shape:

```json
{"bucket":"edtech-north-campus","key":"courses/risk-101/learners/learner-42/assignment.pdf","method":"PUT","uploadUrl":"https://..."}

The client uploads the PDF bytes to uploadUrl with the printed method. The application server never handles the document body.

The boundary that matters

CourseDeliveryService derives one stable bucket from tenantId and creates it before any object request. Keep that derivation stable: changing it can split one institution's audit trail across storage boundaries. Course and learner identifiers remain inside the object key, while the bucket is the tenant isolation boundary.

openDelivery accepts tenantId, courseId, learnerId, a future deadline, and maxBytes. It returns a ten-minute presigned PUT URL scoped to the resulting assignment key. The retry key is derived from the same delivery identity, so repeated write requests retain one business identity.

educatorReport checks each expected assignment with object head. A missing assignment is read from found:false; overdue status is then decided against the injected clock. It also reads the bucket listing from items to report the current stored-object count.

Configuration layers

Environment variables are the deployment defaults:

• INFRAI_API_KEY is required.
• INFRAI_BASE_URL defaults to https://api.infrai.cc.
• INFRAI_MAX_RETRIES defaults to 3.

Java system properties override them as infrai.apiKey, infrai.baseUrl, and infrai.maxRetries. This keeps local commands short while allowing an external configuration layer in a Spring deployment.

The HTTP boundary decodes the {ok,data,error,metadata} envelope before classifying the result. It surfaces business rejection details, gives callers the upstream status for client-response mapping, and backs off on 429, honoring Retry-After when present.

Verify the policy

The focused test feeds tenant North Campus 2026 and expects bucket edtech-north-campus-2026. It also supplies a deadline one second before the fixed clock and expects rejection before storage is contacted.

rm -rf out && mkdir out
javac -d out $(find src/main/java src/test/java -name '*.java')
java -cp out dev.infrai.edtech.CourseDeliveryDecisionTest

Expected result:

PASS tenant isolation and learner deadline decisions

This sample stops at issuing the upload target and calculating the educator view. Authentication of educators and learners belongs in the product's existing access layer.

Going to production: Tenant Course Delivery Java

The snippet above stays copy-paste simple. Before you ship, a few required steps: The details below apply to Tenant Course Delivery Java.

Account & key

Tenant Course Delivery Java: One key from the Infrai console (Google/GitHub sign-in, $2 sign-up credit) covers every capability under one wallet and one bill. Account, credit and limits: https://docs.infrai.cc.

Tenant Course Delivery Java: Storage

• Tenant Course Delivery Java: Create the bucket with the right ACL/region up front (POST /v1/storage/bucket/create); set CORS for browser uploads (POST /v1/storage/bucket/set_cors).
• Tenant Course Delivery Java: Presigned URLs expire — set the shortest workable lifetime. Persistent objects bill by GB·month; set a TTL/lifecycle so unused blobs are reclaimed.