Repository: thehubbleproject/hubble-contracts (ts)

Issue:
Persist TransactionStorage
Previously: https://github.com/thehubbleproject/hubble-contracts/issues/548

### Problem

`TransactionStorage` is currently implemented in memory and does not maintain state between process crashes/restarts.

### Solution

Implement `TransactionStorage` using leveldb to persist L2 transaction info and metadata.

Pull request description:
Persist transactions in database
closes #660 

Did not update storageManagerFactory yet. Will update that and integration tests when addressing #624 and #666. 
wdyt?

Patch:
diff --git a/ts/client/database/connection.ts b/ts/client/database/connection.ts
index e366d31..fd0ba9c 100644
--- a/ts/client/database/connection.ts
+++ b/ts/client/database/connection.ts
@@ -10,4 +10,6 @@ export const close = async (): Promise<void> => {
 export const pubkeyDB = sub(db, "pubkey");
 export const stateDB = sub(db, "state");
 export const nodeDB = sub(db, "node");
+// export const batchDB = sub(db, "batch");
+export const txDB = sub(db, "tx");
 export const pubkey2statesDB = sub(db, "pubkey2states");
diff --git a/ts/client/storageEngine/transactions/db.ts b/ts/client/storageEngine/transactions/db.ts
new file mode 100644
index 0000000..fb81729
--- /dev/null
+++ b/ts/client/storageEngine/transactions/db.ts
@@ -0,0 +1,196 @@
+import { arrayify } from "@ethersproject/bytes";
+import {
+    StatusTransitionInvalid,
+    TransactionAlreadyExists,
+    TransactionDoesNotExist
+} from "../../../exceptions";
+import { txDB } from "../../database/connection";
+import { OffchainTx } from "../../features/interface";
+import { TransferOffchainTx } from "../../features/transfer";
+import { Status } from "./constants";
+import {
+    SubmitMeta,
+    SyncMeta,
+    TransactionStatus,
+    TransactionStorage,
+    TransationMessageOrObject
+} from "./interfaces";
+
+/**
+ * levelDB implementation of TransactionStorage
+ */
+export class TransactionDBStorage implements TransactionStorage {
+    private readonly db = txDB;
+
+    public async get(
+        msgOrTxn: TransationMessageOrObject
+    ): Promise<TransactionStatus> {
+        return this.fromDB(this.getMessage(msgOrTxn));
+    }
+
+    public async pending(txn: OffchainTx): Promise<TransactionStatus> {
+        const txnMessage = txn.message();
+        await this.throwIfAlreadyExists(txnMessage);
+
+        const txnStatus = {
+            status: Status.Pending,
+            transaction: txn
+        };
+
+        await this.toDB(txnMessage, txnStatus);
+        return txnStatus;
+    }
+
+    public async submitted(
+        msgOrTxn: TransationMessageOrObject,
+        { batchID, l1TxnHash, l1BlockIncluded }: SubmitMeta
+    ): Promise<TransactionStatus> {
+        const msg = this.getMessage(msgOrTxn);
+        const txnStatus = await this.getStatusOrFail(msg);
+        this.validateStatusTransition(txnStatus.status, Status.Submitted);
+        const submittedTxnStatus = {
+            ...txnStatus,
+            status: Status.Submitted,
+            batchID,
+            l1TxnHash,
+            l1BlockIncluded
+        };
+        await this.toDB(msg, submittedTxnStatus);
+        return submittedTxnStatus;
+    }
+
+    public async finalized(
+        msgOrTxn: TransationMessageOrObject
+    ): Promise<TransactionStatus> {
+        return this.transition(this.getMessage(msgOrTxn), Status.Finalized);
+    }
+
+    public async failed(
+        msgOrTxn: TransationMessageOrObject,
+        detail: string
+    ): Promise<TransactionStatus> {
+        return this.transition(
+            this.getMessage(msgOrTxn),
+            Status.Failed,
+            detail
+        );
+    }
+
+    public async sync(
+        txn: OffchainTx,
+        { batchID, l1TxnHash, l1BlockIncluded, finalized }: SyncMeta
+    ): Promise<TransactionStatus> {
+        const txnMessage = txn.message();
+        await this.throwIfAlreadyExists(txnMessage);
+
+        const status = finalized ? Status.Finalized : Status.Submitted;
+        const txnStatus = {
+            transaction: txn,
+            status,
+            batchID,
+            l1TxnHash,
+            l1BlockIncluded
+        };
+        await this.toDB(txnMessage, txnStatus);
+        return txnStatus;
+    }
+
+    public async count(): Promise<number> {
+        const stream = this.db.createKeyStream();
+        let count = 0;
+        for await (const _ of stream) {
+            count++;
+        }
+        return count;
+    }
+
+    private async throwIfAlreadyExists(txnMessage: string) {
+        try {
+            const itemFound = await this.get(txnMessage);
+            if (itemFound) {
+                throw new TransactionAlreadyExists(txnMessage);
+            }
+        } catch (error) {
+            if (error.name !== "NotFoundError") {
+                throw error;
+            }
+        }
+    }
+
+    private getMessage(msgOrTxn: TransationMessageOrObject): string {
+        if (typeof msgOrTxn === "string") {
+            return msgOrTxn;
+        }
+        return msgOrTxn.message();
+    }
+
+    private async getStatusOrFail(message: string): Promise<TransactionStatus> {
+        try {
+            return await this.get(message);
+        } catch (error) {
+            if (error.name === "NotFoundError") {
+                throw new TransactionDoesNotExist(message);
+            }
+            throw error;
+        }
+    }
+
+    private validateStatusTransition(cur: Status, next: Status) {
+        // Validate transition from pending
+        if (
+            cur === Status.Pending &&
+            (next === Status.Submitted || next === Status.Failed)
+        ) {
+            return;
+            // Validate transition from submited
+        } else if (
+            cur === Status.Submitted &&
+            (next === Status.Finalized || next === Status.Failed)
+        ) {
+            return;
+        }
+        // Fail on everything else
+        throw new StatusTransitionInvalid(cur, next);
+    }
+
+    private async transition(
+        message: string,
+        next: Status,
+        detail?: string
+    ): Promise<TransactionStatus> {
+        const txnStatus = await this.getStatusOrFail(message);
+        this.validateStatusTransition(txnStatus.status, next);
+        const newTxnStatus = {
+            ...txnStatus,
+            status: next,
+            detail
+        };
+        await this.toDB(message, newTxnStatus);
+        return newTxnStatus;
+    }
+
+    private async toDB(msg: string, status: TransactionStatus) {
+        const serialized = JSON.stringify({
+            tx: status.transaction.serialize(),
+            status: status.status,
+            detail: status.detail,
+            batchID: status.batchID,
+            l1TxnHash: status.l1TxnHash,
+            l1BlockIncluded: status.l1BlockIncluded
+        });
+        await this.db.put(msg, serialized);
+    }
+
+    private async fromDB(msg: string): Promise<TransactionStatus> {
+        const object = JSON.parse(await this.db.get(msg));
+
+        return {
+            transaction: TransferOffchainTx.deserialize(arrayify(object.tx)),
+            status: object.status,
+            detail: object.detail,
+            batchID: object.batchID,
+            l1TxnHash: object.l1TxnHash,
+            l1BlockIncluded: object.l1BlockIncluded
+        };
+    }
+}
diff --git a/ts/client/storageEngine/transactions/interfaces.ts b/ts/client/storageEngine/transactions/interfaces.ts
index 052c6bc..2f340c5 100644
--- a/ts/client/storageEngine/transactions/interfaces.ts
+++ b/ts/client/storageEngine/transactions/interfaces.ts
@@ -90,5 +90,5 @@ export interface TransactionStorage {
     /**
      * @returns Current number of transactions.
      */
-    count(): number;
+    count(): Promise<number>;
 }
diff --git a/ts/client/storageEngine/transactions/memory.ts b/ts/client/storageEngine/transactions/memory.ts
index 9923842..8ef14d6 100644
--- a/ts/client/storageEngine/transactions/memory.ts
+++ b/ts/client/storageEngine/transactions/memory.ts
@@ -102,7 +102,7 @@ export class TransactionMemoryStorage implements TransactionStorage {
         return txnStatus;
     }
 
-    public count(): number {
+    public async count(): Promise<number> {
         return Object.keys(this.transactionMessageToStatus).length;
     }
 


Test patch:
diff --git a/test/client/integration.test.ts b/test/client/integration.test.ts
index 21cb4cc..bc6e63c 100644
--- a/test/client/integration.test.ts
+++ b/test/client/integration.test.ts
@@ -169,7 +169,7 @@ describe("Client Integration", function() {
         assert.equal(storageSyncer.batches.count(), numBatches);
         assert.equal(storagePacker.batches.count(), numBatches);
 
-        assert.equal(storageSyncer.transactions.count(), maxTransfers);
-        assert.equal(storagePacker.transactions.count(), maxTransfers);
+        assert.equal(await storageSyncer.transactions.count(), maxTransfers);
+        assert.equal(await storagePacker.transactions.count(), maxTransfers);
     }).timeout(900000);
 });
diff --git a/test/client/transaction.test.ts b/test/client/transaction.test.ts
index 2ad4489..271526a 100644
--- a/test/client/transaction.test.ts
+++ b/test/client/transaction.test.ts
@@ -1,16 +1,20 @@
 import { BigNumber } from "@ethersproject/bignumber";
+import { arrayify } from "@ethersproject/bytes";
 import chai, { assert } from "chai";
 import chaiAsPromised from "chai-as-promised";
+import del from "del";
+import { BlsSigner } from "../../ts/blsSigner";
 import { OffchainTx } from "../../ts/client/features/interface";
 import { TransferOffchainTx } from "../../ts/client/features/transfer";
 import { Status } from "../../ts/client/storageEngine/transactions/constants";
-import { TransactionStorage } from "../../ts/client/storageEngine/transactions/interfaces";
-import { TransactionMemoryStorage } from "../../ts/client/storageEngine/transactions/memory";
+import { TransactionDBStorage } from "../../ts/client/storageEngine/transactions/db";
 import {
     StatusTransitionInvalid,
     TransactionAlreadyExists,
     TransactionDoesNotExist
 } from "../../ts/exceptions";
+import * as mcl from "../../ts/mcl";
+import { randHex } from "../../ts/utils";
 
 chai.use(chaiAsPromised);
 
@@ -21,25 +25,32 @@ const txFactory = (
     fee: number,
     nonce: number
 ): OffchainTx => {
-    return new TransferOffchainTx(
+    const tx = new TransferOffchainTx(
         BigNumber.from(fromIndex),
         BigNumber.from(toIndex),
         BigNumber.from(amount),
         BigNumber.from(fee),
         BigNumber.from(nonce)
     );
+    const signer = BlsSigner.new(arrayify(randHex(32)));
+    tx.signature = signer.sign(tx.message());
+    return tx;
 };
 
-describe("TransactionMemoryStorage", () => {
-    let storage: TransactionStorage;
+describe("TransactionDBStorage", () => {
+    let storage = new TransactionDBStorage();
 
-    beforeEach(function() {
-        storage = new TransactionMemoryStorage();
+    before(async function() {
+        await del("./leveldb/*");
+        await mcl.init();
     });
 
     describe("get", () => {
-        it("returns undefined is transaction has not been added", async function() {
-            assert.isUndefined(await storage.get("abc123"));
+        it("throws error if transaction has not been added", async function() {
+            assert.isRejected(
+                storage.get("abc123"),
+                /.*Key not found in database*/
+            );
         });
 
         it("returns the correct transaction", async function() {
@@ -51,13 +62,13 @@ describe("TransactionMemoryStorage", () => {
 
             await Promise.all(txns.map(async t => storage.pending(t)));
 
-            assert.equal(storage.count(), 2);
+            assert.equal(await storage.count(), 2);
 
             for (const t of txns) {
                 const txnStatus = await storage.get(t.message());
-                assert.equal(txnStatus?.transaction, t);
+                assert.equal(txnStatus?.transaction.hash(), t.hash());
                 const txnStatusFromTx = await storage.get(t);
-                assert.equal(txnStatusFromTx?.transaction, t);
+                assert.equal(txnStatusFromTx?.transaction.hash(), t.hash());
             }
         });
     });
@@ -69,7 +80,7 @@ describe("TransactionMemoryStorage", () => {
                 const txnMsg = txn.message();
 
                 const pendingStatus = await storage.pending(txn);
-                assert.equal(pendingStatus.transaction, txn);
+                assert.equal(pendingStatus.transaction.hash(), txn.hash());
                 assert.equal(pendingStatus.status, Status.Pending);
 
                 const meta = {
@@ -78,7 +89,7 @@ describe("TransactionMemoryStorage", () => {
                     l1BlockIncluded: 101112
                 };
                 const submittedStatus = await storage.submitted(txnMsg, meta);
-                assert.equal(submittedStatus.transaction, txn);
+                assert.equal(submittedStatus.transaction.hash(), txn.hash());
                 assert.equal(submittedStatus.status, Status.Submitted);
                 assert.equal(submittedStatus.batchID, meta.batchID);
                 assert.equal(submittedStatus.l1TxnHash, meta.l1TxnHash);
@@ -88,7 +99,7 @@ describe("TransactionMemoryStorage", () => {
                 );
 
                 const finalizedStatus = await storage.finalized(txnMsg);
-                assert.equal(finalizedStatus.transaction, txn);
+                assert.equal(finalizedStatus.transaction.hash(), txn.hash());
                 assert.equal(finalizedStatus.status, Status.Finalized);
                 assert.equal(finalizedStatus.batchID, meta.batchID);
                 assert.equal(finalizedStatus.l1TxnHash, meta.l1TxnHash);
@@ -99,7 +110,7 @@ describe("TransactionMemoryStorage", () => {
             });
 
             it("properly transitions to failed state from pending", async function() {
-                const txn = txFactory(10, 11, 10101, 101, 0);
+                const txn = txFactory(10, 11, 1010, 101, 0);
                 await storage.pending(txn);
 
                 const detail = "whoops";
@@ -107,13 +118,13 @@ describe("TransactionMemoryStorage", () => {
                     txn.message(),
                     detail
                 );
-                assert.equal(failedStatus.transaction, txn);
+                assert.equal(failedStatus.transaction.hash(), txn.hash());
                 assert.equal(failedStatus.status, Status.Failed);
                 assert.equal(failedStatus.detail, detail);
             });
 
             it("properly transitions to failed state from submitted", async function() {
-                const txn = txFactory(11, 12, 20202, 202, 0);
+                const txn = txFactory(11, 12, 2020, 202, 0);
                 await storage.pending(txn);
                 const meta = {
                     batchID: 111,
@@ -127,7 +138,7 @@ describe("TransactionMemoryStorage", () => {
                     txn.message(),
                     detail
                 );
-                assert.equal(failedStatus.transaction, txn);
+                assert.equal(failedStatus.transaction.hash(), txn.hash());
                 assert.equal(failedStatus.status, Status.Failed);
                 assert.equal(failedStatus.detail, detail);
             });
@@ -234,7 +245,7 @@ describe("TransactionMemoryStorage", () => {
                 finalized: false
             });
 
-            assert.equal(status.transaction, txn);
+            assert.equal(status.transaction.hash(), txn.hash());
             assert.equal(status.status, Status.Submitted);
             assert.equal(status.batchID, meta.batchID);
             assert.equal(status.l1TxnHash, meta.l1TxnHash);
@@ -254,7 +265,7 @@ describe("TransactionMemoryStorage", () => {
                 finalized: true
             });
 
-            assert.equal(status.transaction, txn);
+            assert.equal(status.transaction.hash(), txn.hash());
             assert.equal(status.status, Status.Finalized);
             assert.equal(status.batchID, meta.batchID);
             assert.equal(status.l1TxnHash, meta.l1TxnHash);