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Provider duplicate-purchase proof matrix: Azure Savings Plans has no server-side dedupe #838
Description
Provider duplicate-purchase proof matrix (platform#631 B4)
Platform side: every recommendation of an execution receives DeriveIdempotencyToken(lineage, index) and a re-drive reuses it (TestRedriveReusesDerivedTokensForEveryProvider). Where the pinned cloud-commitments-go module (go.mod, ad67030387e4) uses that token, and where it is tested there:
| Provider / service | Token use | Proof in the module |
|---|---|---|
| AWS Savings Plans | CreateSavingsPlanInput.ClientToken (services/savingsplans/client.go:247) |
services/savingsplans/client_test.go |
| AWS RDS, ElastiCache, MemoryDB, OpenSearch | deterministic reservation ID + idempotencyGuard / recoverAlreadyExists |
services/rds/client_test.go PurchaseCommitment_Idempotent_* (others share the helper) |
| AWS EC2, Redshift | tag lookup by token before buying (ec2/client.go:139, redshift/client.go:177) | ec2/client_test.go, redshift/client_test.go Idempotent_ScanBoundaries; the platform still REFUSES re-drive (recRedriveRefusalReason) |
| Azure compute, cache, cosmosdb, database, managedredis, search, synapse | DoIdempotentPurchaseTwoStep with the token tag and reservation-order lookup |
services/internal/reservations/purchase_test.go |
| GCP Compute Engine | RequestId from IdempotencyGUID(token) plus deterministic name (computeengine/client.go:931) |
computeengine/client_test.go:775-806 |
No proof / no guard (double-buy risk if re-driven):
- Azure Savings Plans: alias name from
time.Now().UnixNano()(services/savingsplans/client.go:373), no server-side dedupe. Platform refuses re-drive (recRedriveRefusalReason,TestRedriveRefusedWhereNoProviderGuardExists), so the risk is only a first attempt whose response is lost. - AWS EC2 / Redshift: the module now looks up by tag, but the lookup is a scan with documented boundaries; the platform conservatively refuses re-drive. Not a risk; an opportunity to relax once the scan is trusted.
- GCP Cloud SQL, Cloud Storage, Memorystore:
PurchaseCommitmentreturns an error (no purchase API), so nothing can be bought or doubled. - Any other provider name: refused on re-drive.
Ask: decide whether to (a) keep refusing Azure Savings Plans re-drive permanently, or (b) add a server-side dedupe upstream; and whether to relax the EC2/Redshift refusal.
Refs #631
Activity
IAmJSD commentedon Oct 23, 2026
Claiming: working on this
test(purchase): pin the Azure savings-plans alias to the re-drive tok…
IAmJSD commentedon Oct 26, 2026
Owner decision (IAmJSD, acting owner, 2026-10-26, D18): keep refusing automatic re-drive for Azure Savings Plans, and keep the EC2 and Redshift re-drive refusals as they are. The safe path is to look up the existing order alias before buying; that's tracked in LeanerCloud/cloud-commitments-go#624, to be built after the Azure deploy pause. #1305 (merged) pins the alias to the re-drive token.
IAmJSD commentedon Oct 26, 2026
Closing as done. The owner decided (D18 in the acting-owner report) to accept the Azure Savings Plans gap in the duplicate-purchase proof matrix as documented, and #1305 added the test that pins the matrix. The library-side follow-up is LeanerCloud/cloud-commitments-go#624.
Checked against main at
3bfc2fe5. Closed by IAmJSD's agent at IAmJSD's request (acting owner) as part of a sweep of stale assigned issues; reopen if anything is missing.IAmJSD commentedon Oct 26, 2026
Correction to the closing note above: D18 was to keep refusing automatic re-drive for Azure Savings Plans (and keep the EC2 and Redshift refusals), not to accept a gap. #1305 (merged) pins the order alias to the re-drive token. The safe re-drive path, looking up the existing order alias before buying, is tracked in LeanerCloud/cloud-commitments-go#624.