[server] Fix usage of AccountStatementProvider by making it cache per userId

Author: geropl

components/gitpod-protocol/src/util/garbage-collected-cache.ts

@@ -37,6 +37,11 @@ export class GarbageCollectedCache<T> {
         if (!entry) {
             return undefined;
         }
+        // Still valid?
+        if (entry.expiryDate < Date.now()) {
+            this.store.delete(entry.key);
+            return undefined;
+        }
         return entry.value;
     }
 

components/server/ee/src/billing/entitlement-service-chargebee.ts

@@ -79,7 +79,7 @@ export class EntitlementServiceChargebee implements EntitlementService {
         runningInstances: Promise<WorkspaceInstance[]>,
     ): Promise<boolean> {
         // As retrieving a full AccountStatement is expensive we want to cache it as much as possible.
-        const cachedAccountStatement = this.accountStatementProvider.getCachedStatement();
+        const cachedAccountStatement = this.accountStatementProvider.getCachedStatement(userId);
         const lowerBound = this.getRemainingUsageHoursLowerBound(cachedAccountStatement, date.toISOString());
         if (lowerBound && (lowerBound === "unlimited" || lowerBound > Accounting.MINIMUM_CREDIT_FOR_OPEN_IN_HOURS)) {
             return true;
@@ -108,7 +108,7 @@ export class EntitlementServiceChargebee implements EntitlementService {
             return "unlimited";
         }
 
-        const diffInMillis = new Date(cachedStatement.endDate).getTime() - new Date(date).getTime();
+        const diffInMillis = Math.max(0, new Date(cachedStatement.endDate).getTime() - new Date(date).getTime());
         const maxPossibleUsage = millisecondsToHours(diffInMillis) * MAX_PARALLEL_WORKSPACES;
         return cachedStatement.remainingHours - maxPossibleUsage;
     }

components/server/ee/src/container-module.ts

@@ -94,13 +94,13 @@ export const productionEEContainerModule = new ContainerModule((bind, unbind, is
     // GitpodServerImpl (stateful per user)
     rebind(GitpodServerImpl).to(GitpodServerEEImpl).inRequestScope();
     bind(EligibilityService).toSelf().inRequestScope();
-    bind(AccountStatementProvider).toSelf().inRequestScope();
 
     // various
     rebind(HostContainerMapping).to(HostContainerMappingEE).inSingletonScope();
     bind(EMailDomainService).to(EMailDomainServiceImpl).inSingletonScope();
     rebind(BlockedUserFilter).toService(EMailDomainService);
     bind(SnapshotService).toSelf().inSingletonScope();
+    bind(AccountStatementProvider).toSelf().inSingletonScope();
 
     bind(UserDeletionServiceEE).toSelf().inSingletonScope();
     rebind(UserDeletionService).to(UserDeletionServiceEE).inSingletonScope();

components/server/ee/src/user/account-statement-provider.ts

@@ -8,6 +8,7 @@ import { injectable, inject } from "inversify";
 import { WorkspaceInstance } from "@gitpod/gitpod-protocol";
 import { AccountStatement } from "@gitpod/gitpod-protocol/lib/accounting-protocol";
 import { AccountService } from "@gitpod/gitpod-payment-endpoint/lib/accounting";
+import { GarbageCollectedCache } from "@gitpod/gitpod-protocol/lib/util/garbage-collected-cache";
 
 export type CachedAccountStatement = Pick<AccountStatement, "remainingHours" | "endDate">;
 
@@ -19,20 +20,18 @@ export type CachedAccountStatement = Pick<AccountStatement, "remainingHours" | "
 export class AccountStatementProvider {
     @inject(AccountService) protected readonly accountService: AccountService;
 
-    protected cachedStatement: CachedAccountStatement | undefined;
+    /**
+     * AccountStatements, cached by userId
+     */
+    protected readonly cachedStatements = new GarbageCollectedCache<CachedAccountStatement>(5 * 60, 10 * 60);
 
-    setCachedStatement(cachedStatement: CachedAccountStatement) {
-        this.cachedStatement = cachedStatement;
-    }
-
-    getCachedStatement(): CachedAccountStatement | undefined {
-        return this.cachedStatement;
+    getCachedStatement(userId: string): CachedAccountStatement | undefined {
+        return this.cachedStatements.get(userId);
     }
 
     async getAccountStatement(userId: string, date: string): Promise<AccountStatement> {
         const statement = await this.accountService.getAccountStatement(userId, date);
-        // Fill cache
-        this.setCachedStatement({
+        this.cachedStatements.set(userId, {
             remainingHours: statement.remainingHours,
             endDate: statement.endDate,
         });