Merge pull request #9835 from Budibase/bug/budi-5901-usage-quota-document-conflicts-can-cause

Bug - budi-5901 usage quota document conflicts can cause

packages/backend-core/src/cache/tests/writethrough.spec.ts

@@ -1,10 +1,13 @@
-import { structures, DBTestConfiguration } from "../../../tests"
+import {
+  structures,
+  DBTestConfiguration,
+  expectFunctionWasCalledTimesWith,
+} from "../../../tests"
 import { Writethrough } from "../writethrough"
 import { getDB } from "../../db"
 import tk from "timekeeper"
 
-const START_DATE = Date.now()
-tk.freeze(START_DATE)
+tk.freeze(Date.now())
 
 const DELAY = 5000
 
@@ -17,34 +20,99 @@ describe("writethrough", () => {
   const writethrough = new Writethrough(db, DELAY)
   const writethrough2 = new Writethrough(db2, DELAY)
 
+  const docId = structures.uuid()
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+  })
+
   describe("put", () => {
-    let first: any
+    let current: any
 
     it("should be able to store, will go to DB", async () => {
       await config.doInTenant(async () => {
-        const response = await writethrough.put({ _id: "test", value: 1 })
+        const response = await writethrough.put({
+          _id: docId,
+          value: 1,
+        })
         const output = await db.get(response.id)
-        first = output
+        current = output
         expect(output.value).toBe(1)
       })
     })
 
     it("second put shouldn't update DB", async () => {
       await config.doInTenant(async () => {
-        const response = await writethrough.put({ ...first, value: 2 })
+        const response = await writethrough.put({ ...current, value: 2 })
         const output = await db.get(response.id)
-        expect(first._rev).toBe(output._rev)
+        expect(current._rev).toBe(output._rev)
         expect(output.value).toBe(1)
       })
     })
 
     it("should put it again after delay period", async () => {
       await config.doInTenant(async () => {
-        tk.freeze(START_DATE + DELAY + 1)
-        const response = await writethrough.put({ ...first, value: 3 })
+        tk.freeze(Date.now() + DELAY + 1)
+        const response = await writethrough.put({ ...current, value: 3 })
         const output = await db.get(response.id)
-        expect(response.rev).not.toBe(first._rev)
+        expect(response.rev).not.toBe(current._rev)
         expect(output.value).toBe(3)
+
+        current = output
+      })
+    })
+
+    it("should handle parallel DB updates ignoring conflicts", async () => {
+      await config.doInTenant(async () => {
+        tk.freeze(Date.now() + DELAY + 1)
+        const responses = await Promise.all([
+          writethrough.put({ ...current, value: 4 }),
+          writethrough.put({ ...current, value: 4 }),
+          writethrough.put({ ...current, value: 4 }),
+        ])
+
+        const newRev = responses.map(x => x.rev).find(x => x !== current._rev)
+        expect(newRev).toBeDefined()
+        expect(responses.map(x => x.rev)).toEqual(
+          expect.arrayContaining([current._rev, current._rev, newRev])
+        )
+        expectFunctionWasCalledTimesWith(
+          console.warn,
+          2,
+          "bb-warn: Ignoring redlock conflict in write-through cache"
+        )
+
+        const output = await db.get(current._id)
+        expect(output.value).toBe(4)
+        expect(output._rev).toBe(newRev)
+
+        current = output
+      })
+    })
+
+    it("should handle updates with documents falling behind", async () => {
+      await config.doInTenant(async () => {
+        tk.freeze(Date.now() + DELAY + 1)
+
+        const id = structures.uuid()
+        await writethrough.put({ _id: id, value: 1 })
+        const doc = await writethrough.get(id)
+
+        // Updating document
+        tk.freeze(Date.now() + DELAY + 1)
+        await writethrough.put({ ...doc, value: 2 })
+
+        // Update with the old rev value
+        tk.freeze(Date.now() + DELAY + 1)
+        const res = await writethrough.put({
+          ...doc,
+          value: 3,
+        })
+        expect(res.ok).toBe(true)
+
+        const output = await db.get(id)
+        expect(output.value).toBe(3)
+        expect(output._rev).toBe(res.rev)
       })
     })
   })
@@ -52,8 +120,8 @@ describe("writethrough", () => {
   describe("get", () => {
     it("should be able to retrieve", async () => {
       await config.doInTenant(async () => {
-        const response = await writethrough.get("test")
-        expect(response.value).toBe(3)
+        const response = await writethrough.get(docId)
+        expect(response.value).toBe(4)
       })
     })
   })

packages/backend-core/src/cache/writethrough.ts

@@ -1,7 +1,8 @@
 import BaseCache from "./base"
 import { getWritethroughClient } from "../redis/init"
 import { logWarn } from "../logging"
-import { Database } from "@budibase/types"
+import { Database, Document, LockName, LockType } from "@budibase/types"
+import * as locks from "../redis/redlockImpl"
 
 const DEFAULT_WRITE_RATE_MS = 10000
 let CACHE: BaseCache | null = null
@@ -27,20 +28,31 @@ function makeCacheItem(doc: any, lastWrite: number | null = null): CacheItem {
   return { doc, lastWrite: lastWrite || Date.now() }
 }
 
-export async function put(
+async function put(
   db: Database,
-  doc: any,
+  doc: Document,
   writeRateMs: number = DEFAULT_WRITE_RATE_MS
 ) {
   const cache = await getCache()
   const key = doc._id
-  let cacheItem: CacheItem | undefined = await cache.get(makeCacheKey(db, key))
+  let cacheItem: CacheItem | undefined
+  if (key) {
+    cacheItem = await cache.get(makeCacheKey(db, key))
+  }
   const updateDb = !cacheItem || cacheItem.lastWrite < Date.now() - writeRateMs
   let output = doc
   if (updateDb) {
+    const lockResponse = await locks.doWithLock(
+      {
+        type: LockType.TRY_ONCE,
+        name: LockName.PERSIST_WRITETHROUGH,
+        resource: key,
+        ttl: 1000,
+      },
+      async () => {
         const writeDb = async (toWrite: any) => {
           // doc should contain the _id and _rev
-      const response = await db.put(toWrite)
+          const response = await db.put(toWrite, { force: true })
           output = {
             ...doc,
             _id: response.id,
@@ -58,13 +70,20 @@ export async function put(
           }
         }
       }
+    )
+    if (!lockResponse.executed) {
+      logWarn(`Ignoring redlock conflict in write-through cache`)
+    }
+  }
   // if we are updating the DB then need to set the lastWrite to now
   cacheItem = makeCacheItem(output, updateDb ? null : cacheItem?.lastWrite)
-  await cache.store(makeCacheKey(db, key), cacheItem)
+  if (output._id) {
+    await cache.store(makeCacheKey(db, output._id), cacheItem)
+  }
   return { ok: true, id: output._id, rev: output._rev }
 }
 
-export async function get(db: Database, id: string): Promise<any> {
+async function get(db: Database, id: string): Promise<any> {
   const cache = await getCache()
   const cacheKey = makeCacheKey(db, id)
   let cacheItem: CacheItem = await cache.get(cacheKey)
@@ -76,11 +95,7 @@ export async function get(db: Database, id: string): Promise<any> {
   return cacheItem.doc
 }
 
-export async function remove(
-  db: Database,
-  docOrId: any,
-  rev?: any
-): Promise<void> {
+async function remove(db: Database, docOrId: any, rev?: any): Promise<void> {
   const cache = await getCache()
   if (!docOrId) {
     throw new Error("No ID/Rev provided.")

packages/backend-core/src/redis/redlockImpl.ts

@@ -24,7 +24,7 @@ const getClient = async (type: LockType): Promise<Redlock> => {
   }
 }
 
-export const OPTIONS = {
+const OPTIONS = {
   TRY_ONCE: {
     // immediately throws an error if the lock is already held
     retryCount: 0,
@@ -56,14 +56,29 @@ export const OPTIONS = {
   },
 }
 
-export const newRedlock = async (opts: Options = {}) => {
+const newRedlock = async (opts: Options = {}) => {
   let options = { ...OPTIONS.DEFAULT, ...opts }
   const redisWrapper = await getLockClient()
   const client = redisWrapper.getClient()
   return new Redlock([client], options)
 }
 
-export const doWithLock = async (opts: LockOptions, task: any) => {
+type SuccessfulRedlockExecution<T> = {
+  executed: true
+  result: T
+}
+type UnsuccessfulRedlockExecution = {
+  executed: false
+}
+
+type RedlockExecution<T> =
+  | SuccessfulRedlockExecution<T>
+  | UnsuccessfulRedlockExecution
+
+export const doWithLock = async <T>(
+  opts: LockOptions,
+  task: () => Promise<T>
+): Promise<RedlockExecution<T>> => {
   const redlock = await getClient(opts.type)
   let lock
   try {
@@ -73,8 +88,8 @@ export const doWithLock = async (opts: LockOptions, task: any) => {
     let name: string = `lock:${prefix}_${opts.name}`
 
     // add additional unique name if required
-    if (opts.nameSuffix) {
-      name = name + `_${opts.nameSuffix}`
+    if (opts.resource) {
+      name = name + `_${opts.resource}`
     }
 
     // create the lock
@@ -83,7 +98,7 @@ export const doWithLock = async (opts: LockOptions, task: any) => {
     // perform locked task
     // need to await to ensure completion before unlocking
     const result = await task()
-    return result
+    return { executed: true, result }
   } catch (e: any) {
     console.warn("lock error")
     // lock limit exceeded
@@ -92,7 +107,7 @@ export const doWithLock = async (opts: LockOptions, task: any) => {
         // don't throw for try-once locks, they will always error
         // due to retry count (0) exceeded
         console.warn(e)
-        return
+        return { executed: false }
       } else {
         console.error(e)
         throw e

packages/backend-core/tests/utilities/index.ts

@@ -4,4 +4,6 @@ export { generator } from "./structures"
 export * as testEnv from "./testEnv"
 export * as testContainerUtils from "./testContainerUtils"
 
+export * from "./jestUtils"
+
 export { default as DBTestConfiguration } from "./DBTestConfiguration"

packages/backend-core/tests/utilities/jestUtils.ts

@@ -0,0 +1,9 @@
+export function expectFunctionWasCalledTimesWith(
+  jestFunction: any,
+  times: number,
+  argument: any
+) {
+  expect(
+    jestFunction.mock.calls.filter((call: any) => call[0] === argument).length
+  ).toBe(times)
+}

packages/backend-core/tests/utilities/structures/db.ts

@@ -1,5 +1,12 @@
+import { structures } from ".."
 import { newid } from "../../../src/newid"
 
 export function id() {
   return `db_${newid()}`
 }
+
+export function rev() {
+  return `${structures.generator.character({
+    numeric: true,
+  })}-${structures.uuid().replace(/-/, "")}`
+}

packages/types/src/sdk/locks.ts

@@ -13,6 +13,7 @@ export enum LockName {
   TRIGGER_QUOTA = "trigger_quota",
   SYNC_ACCOUNT_LICENSE = "sync_account_license",
   UPDATE_TENANTS_DOC = "update_tenants_doc",
+  PERSIST_WRITETHROUGH = "persist_writethrough",
 }
 
 export interface LockOptions {
@@ -29,9 +30,9 @@ export interface LockOptions {
    */
   ttl: number
   /**
-   * The suffix to add to the lock name for additional uniqueness
+   * The individual resource to lock. This is useful for locking around very specific identifiers, e.g. a document that is prone to conflicts
    */
-  nameSuffix?: string
+  resource?: string
   /**
    * This is a system-wide lock - don't use tenancy in lock key
    */