fix(azure/cache): refuse Redis purchases so only managedredis buys them

CHANGELOG.md

@@ -7,6 +7,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/).
 
 ### Notices
 
+- **Azure Redis purchases must go through managedredis (`ServiceMemoryDB`).**
+  The Azure recommendations adapter still labels Redis recommendations
+  `ServiceCache`, and the cache client now refuses every purchase (#538), so
+  route Azure Redis purchases to the managedredis client. The refusal wraps
+  `common.ErrRefusedBeforePurchase` (nothing was sent), not an upfront-approval
+  failure, so approving and retrying does not help.
 - **Federation IaC bundles downloaded before 2026-04-22 need to be
   re-downloaded** to get zero-touch registration. Older bundles silently
   skip auto-registration unless manually edited (Terraform `registration.tf`
@@ -179,6 +185,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/).
 ### Changed
 
 - **BREAKING `azure`:** Azure Redis recommendations now come only from managedredis and are labelled `memorydb` (`ServiceMemoryDB`), both from Consumption and from Advisor rows. The cache client's `GetRecommendations` returns none, so `GetRecommendationsForService(ServiceCache)` is empty for Azure, and consumers that stored Azure Redis plans or settings under `cache` must also match `memorydb`. Azure Redis recommendations keep `CacheDetails` `Engine` and `NodeType` but no longer report `Shards` (0, unknown) (#692).
+- **`azure`:** the cache service no longer purchases Azure Redis reservations;
+  managedredis (`ServiceMemoryDB`) is the only service that buys `RedisCache`,
+  so one Redis recommendation cannot be bought once through each service.
+  `cache.PurchaseCommitment` now refuses before any API call with an error
+  wrapping `common.ErrRefusedBeforePurchase`. Consumers that buy an Azure
+  `ServiceCache` recommendation must route it to managedredis (#538).
 - `ListTargetOfferings` now walks up to 50 pages (about 5000 offerings)
   instead of 10, and returns an error wrapping the new
   `ec2.ErrTargetOfferingsTruncated` (with no list) when that bound is hit,

providers/azure/go.mod

@@ -15,16 +15,16 @@ require (
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/resources/armsubscriptions v1.3.0
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/search/armsearch v1.4.0
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/sql/armsql v1.2.0
-	github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20261026141505-6c5673cd5518
+	github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20261104063122-3efa339480ac
 	github.com/stretchr/testify v1.12.1
 	golang.org/x/sync v0.24.0
 )
 
 require (
 	github.com/Azure/azure-sdk-for-go/sdk/internal v1.13.0 // indirect
 	github.com/AzureAD/microsoft-authentication-library-for-go v1.10.1 // indirect
-	github.com/aws/aws-sdk-go-v2 v1.41.5 // indirect
-	github.com/aws/smithy-go v1.24.2 // indirect
+	github.com/aws/aws-sdk-go-v2 v1.47.4 // indirect
+	github.com/aws/smithy-go v1.28.6 // indirect
 	github.com/golang-jwt/jwt/v5 v5.3.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/kylelemons/godebug v1.1.0 // indirect

providers/azure/go.sum

@@ -36,12 +36,12 @@ github.com/AzureAD/microsoft-authentication-extensions-for-go/cache v0.1.1 h1:WJ
 github.com/AzureAD/microsoft-authentication-extensions-for-go/cache v0.1.1/go.mod h1:tCcJZ0uHAmvjsVYzEFivsRTN00oz5BEsRgQHu5JZ9WE=
 github.com/AzureAD/microsoft-authentication-library-for-go v1.10.1 h1:0O6j18nQDoIff6/mtosT5LNU2WehEwp+LqfX6699oqY=
 github.com/AzureAD/microsoft-authentication-library-for-go v1.10.1/go.mod h1:xdYAf5bjkOpsd3auA8riiJW4vneBubt9caavL7626jQ=
-github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20261026141505-6c5673cd5518 h1:2wyUUf+lBH+Qo3ULGiHOhn9drt+WyqLoR8fV/3q21a0=
-github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20261026141505-6c5673cd5518/go.mod h1:rEJErEsL40Np/ttf0RDoNNC2XQsN1GmWyFf34y0JLD8=
-github.com/aws/aws-sdk-go-v2 v1.41.5 h1:dj5kopbwUsVUVFgO4Fi5BIT3t4WyqIDjGKCangnV/yY=
-github.com/aws/aws-sdk-go-v2 v1.41.5/go.mod h1:mwsPRE8ceUUpiTgF7QmQIJ7lgsKUPQOUl3o72QBrE1o=
-github.com/aws/smithy-go v1.24.2 h1:FzA3bu/nt/vDvmnkg+R8Xl46gmzEDam6mZ1hzmwXFng=
-github.com/aws/smithy-go v1.24.2/go.mod h1:YE2RhdIuDbA5E5bTdciG9KrW3+TiEONeUWCqxX9i1Fc=
+github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20261104063122-3efa339480ac h1:EvEUCt1uH5oBtPcJJPt1mX6XYQWAKtL9QBSo9CfeaOw=
+github.com/LeanerCloud/cloud-commitments-go/pkg v0.0.0-20261104063122-3efa339480ac/go.mod h1:pseCFRgm1rzBKomktjw6E0ayxmVE7XfHHiOmew4ka+g=
+github.com/aws/aws-sdk-go-v2 v1.47.4 h1:bTvk6UdSSSvaQsfLVj1JRDEEqj/PDRwGf1KanaRzau0=
+github.com/aws/aws-sdk-go-v2 v1.47.4/go.mod h1:XkrjAZvr705Nytv6PkPUhoSB2W9+vVHBp5oAWpkh8Ak=
+github.com/aws/smithy-go v1.28.6 h1:Pj+/sUviNYjow8ELRtNwKHZ9ECeF+7pATX3+shjLIrw=
+github.com/aws/smithy-go v1.28.6/go.mod h1:YE2RhdIuDbA5E5bTdciG9KrW3+TiEONeUWCqxX9i1Fc=
 github.com/golang-jwt/jwt/v5 v5.3.1 h1:kYf81DTWFe7t+1VvL7eS+jKFVWaUnK9cB1qbwn63YCY=
 github.com/golang-jwt/jwt/v5 v5.3.1/go.mod h1:fxCRLWMO43lRc8nhHWY6LGqRcf+1gQWArsqaEUEa5bE=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=

providers/azure/services/cache/client.go

@@ -12,7 +12,6 @@ import (
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore"
 	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/consumption/armconsumption"
 	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/redis/armredis/v3"
-	"github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/reservations/armreservations"
 
 	"github.com/LeanerCloud/cloud-commitments-go/pkg/common"
 	"github.com/LeanerCloud/cloud-commitments-go/providers/azure/internal/httpclient"
@@ -201,79 +200,12 @@ func (c *Client) convertRedisReservation(detail *armconsumption.ReservationDetai
 	return commitment
 }
 
-// PurchaseCommitment purchases Redis Cache reserved capacity using the two-step
-// calculatePrice->purchase flow required by Azure's Reservations API (issue #677).
-func (c *Client) PurchaseCommitment(ctx context.Context, rec common.Recommendation, opts common.PurchaseOptions) (common.PurchaseResult, error) {
-	result := common.PurchaseResult{
-		Recommendation: rec,
-		DryRun:         false,
-		Success:        false,
-		Timestamp:      time.Now(),
-	}
-
-	// Source is required so the resulting reservation is attributable to CUDly
-	// in the portal via the purchase-automation tag. The dedupe key for
-	// idempotent re-drives is now opts.IdempotencyToken (issue #721, applied
-	// in reservations.DoIdempotentPurchaseTwoStep); source remains mandatory
-	// for attribution.
-	if opts.Source == "" {
-		result.Error = fmt.Errorf("purchase source is required for Azure reservation purchases")
-		return result, result.Error
-	}
-	if strings.TrimSpace(rec.ResourceType) == "" {
-		result.Error = fmt.Errorf("resource type is required")
-		return result, result.Error
-	}
-	if rec.Count <= 0 {
-		result.Error = fmt.Errorf("quantity must be greater than zero, got %d", rec.Count)
-		return result, result.Error
-	}
-
-	termYears, termErr := reservations.ParseTermYears(rec.Term)
-	if termErr != nil {
-		result.Error = termErr
-		return result, result.Error
-	}
-	if _, termEnumErr := reservations.ReservationTermForYears(termYears); termEnumErr != nil {
-		result.Error = termEnumErr
-		return result, result.Error
-	}
-	billingPlan, billingPlanErr := reservations.BillingPlanForPaymentOption(rec.PaymentOption)
-	if billingPlanErr != nil {
-		result.Error = billingPlanErr
-		return result, result.Error
-	}
-
-	bodyBytes, err := reservations.BuildPurchaseBody(reservations.PurchaseParams{
-		ReservedResourceType: string(armreservations.ReservedResourceTypeRedisCache),
-		DisplayName: func(r common.Recommendation) string {
-			return reservations.BuildDisplayName(reservations.DisplayNameFields{
-				Service:      "redis",
-				Region:       c.region,
-				ResourceType: r.ResourceType,
-				Count:        r.Count,
-				Term:         r.Term,
-				Payment:      r.PaymentOption,
-				Now:          time.Now(),
-			})
-		},
-	}, rec, opts, c.region, c.subscriptionID, billingPlan)
-	if err != nil {
-		result.Error = fmt.Errorf("failed to marshal request: %w", err)
-		return result, result.Error
-	}
-
-	reservationOrderID, existing, err := reservations.Submit(ctx, c.cred, c.httpClient, bodyBytes, opts, rec.CommitmentCurrency)
-	if err != nil {
-		result.Error = err
-		return result, result.Error
-	}
-
-	result.Success = true
-	result.ExistingCommitment = existing
-	result.CommitmentID = reservationOrderID
-	result.Cost = reservations.UpfrontCostForBillingPlan(billingPlan)
-	return result, nil
+// PurchaseCommitment refuses: managedredis (ServiceMemoryDB) is the only Azure service that
+// buys RedisCache reservations (#538), so one Redis recommendation cannot be bought twice.
+func (c *Client) PurchaseCommitment(_ context.Context, rec common.Recommendation, _ common.PurchaseOptions) (common.PurchaseResult, error) {
+	err := fmt.Errorf("%w: Azure Redis reservations are purchased through the %s service, not %s",
+		common.ErrRefusedBeforePurchase, common.ServiceMemoryDB, common.ServiceCache)
+	return common.PurchaseResult{Recommendation: rec, Timestamp: time.Now(), Error: err}, err
 }
 
 // ValidateOffering validates that a Redis Cache SKU exists.