feat(locking): Locking module (#9524)

**What**
- Locking Module to manage concurrency
- Default `in-memory` provider

packages/modules/locking/integration-tests/__tests__/index.spec.ts

@@ -0,0 +1,122 @@
+import { ILockingModule } from "@medusajs/framework/types"
+import { Modules } from "@medusajs/framework/utils"
+import { moduleIntegrationTestRunner } from "medusa-test-utils"
+import { setTimeout } from "node:timers/promises"
+
+jest.setTimeout(10000)
+
+moduleIntegrationTestRunner<ILockingModule>({
+  moduleName: Modules.LOCKING,
+  testSuite: ({ service }) => {
+    describe("Locking Module Service", () => {
+      let stock = 5
+      function replenishStock() {
+        stock = 5
+      }
+      function hasStock() {
+        return stock > 0
+      }
+      async function reduceStock() {
+        await setTimeout(10)
+        stock--
+      }
+      async function buy() {
+        if (hasStock()) {
+          await reduceStock()
+          return true
+        }
+        return false
+      }
+
+      it("should execute functions respecting the key locked", async () => {
+        // 10 parallel calls to buy should oversell the stock
+        const prom: any[] = []
+        for (let i = 0; i < 10; i++) {
+          prom.push(buy())
+        }
+        await Promise.all(prom)
+        expect(stock).toBe(-5)
+
+        replenishStock()
+
+        // 10 parallel calls to buy with lock should not oversell the stock
+        const promWLock: any[] = []
+        for (let i = 0; i < 10; i++) {
+          promWLock.push(service.execute("item_1", buy))
+        }
+        await Promise.all(promWLock)
+
+        expect(stock).toBe(0)
+      })
+
+      it("should acquire lock and release it", async () => {
+        await service.acquire("key_name", {
+          ownerId: "user_id_123",
+        })
+
+        const userReleased = await service.release("key_name", {
+          ownerId: "user_id_456",
+        })
+        const anotherUserLock = service.acquire("key_name", {
+          ownerId: "user_id_456",
+        })
+
+        expect(userReleased).toBe(false)
+        await expect(anotherUserLock).rejects.toThrowError(
+          `"key_name" is already locked.`
+        )
+
+        const releasing = await service.release("key_name", {
+          ownerId: "user_id_123",
+        })
+
+        expect(releasing).toBe(true)
+      })
+
+      it("should acquire lock and release it during parallel calls", async () => {
+        const keyToLock = "mySpecialKey"
+        const user_1 = {
+          ownerId: "user_id_456",
+        }
+        const user_2 = {
+          ownerId: "user_id_000",
+        }
+
+        expect(service.acquire(keyToLock, user_1)).resolves.toBeUndefined()
+
+        expect(service.acquire(keyToLock, user_1)).resolves.toBeUndefined()
+
+        expect(service.acquire(keyToLock, user_2)).rejects.toThrowError(
+          `"${keyToLock}" is already locked.`
+        )
+
+        expect(service.acquire(keyToLock, user_2)).rejects.toThrowError(
+          `"${keyToLock}" is already locked.`
+        )
+
+        await service.acquire(keyToLock, user_1)
+
+        const releaseNotLocked = await service.release(keyToLock, {
+          ownerId: "user_id_000",
+        })
+        expect(releaseNotLocked).toBe(false)
+
+        const release = await service.release(keyToLock, user_1)
+        expect(release).toBe(true)
+      })
+    })
+
+    it("should release lock in case of failure", async () => {
+      const fn_1 = jest.fn(async () => {
+        throw new Error("Error")
+      })
+      const fn_2 = jest.fn(async () => {})
+
+      await service.execute("lock_key", fn_1).catch(() => {})
+      await service.execute("lock_key", fn_2).catch(() => {})
+
+      expect(fn_1).toBeCalledTimes(1)
+      expect(fn_2).toBeCalledTimes(1)
+    })
+  },
+})