Adding index to local cache

zp-relayer/pool/RelayPool.ts

@@ -262,7 +262,7 @@ export class RelayPool extends BasePool<Network> {
     }
 
     // cache transaction locally
-    await this.cacheTxLocally(outCommit, txHash, memo);
+    await this.cacheTxLocally(outCommit, txHash, memo, commitIndex);
     // start monitoring local cache against the indexer to cleanup already indexed txs
     this.startLocalCacheObserver(commitIndex);
   }
@@ -278,7 +278,7 @@ export class RelayPool extends BasePool<Network> {
         poolJob.data.transaction.txHash = txHash;
         await poolJob.update(poolJob.data);
 
-        await this.cacheTxLocally(res.outCommit, txHash, res.memo);
+        await this.cacheTxLocally(res.outCommit, txHash, res.memo, res.commitIndex);
       }
     }
   }
@@ -296,15 +296,15 @@ export class RelayPool extends BasePool<Network> {
     }
   }
 
-  protected async cacheTxLocally(commit: string, txHash: string, memo: string) {
+  protected async cacheTxLocally(commit: string, txHash: string, memo: string, index: number) {
     // store or updating local tx store
     // (we should keep sent transaction until the indexer grab them)
     const prefixedMemo = buildPrefixedMemo(
       commit,
       txHash,
       memo
     );
-    await this.txStore.add(commit, prefixedMemo);
+    await this.txStore.add(commit, prefixedMemo, index);
     logger.info(`Tx with commit ${commit} has been CACHED locally`);
   }
 

zp-relayer/state/TxStore.ts

@@ -1,23 +1,39 @@
+import { hexToNumber, numberToHexPadded } from '@/utils/helpers';
 import type { Redis } from 'ioredis'
 
+const INDEX_BYTES = 6;
+
 export class TxStore {
   constructor(public name: string, private redis: Redis) {}
 
-  async add(commitment: string, memo: string) {
-    await this.redis.hset(this.name, { [commitment]: memo })
+  async add(commitment: string, memo: string, index: number) {
+    await this.redis.hset(this.name, { [commitment]: `${numberToHexPadded(index, INDEX_BYTES)}${memo}` })
   }
 
   async remove(commitment: string) {
     await this.redis.hdel(this.name, commitment)
   }
 
-  async get(commitment: string) {
-    const memo = await this.redis.hget(this.name, commitment)
-    return memo
+  async get(commitment: string): Promise<{memo: string, index: number} | null> {
+    const data = await this.redis.hget(this.name, commitment);
+
+    return data ? { 
+      memo: data.slice(INDEX_BYTES * 2),
+      index: hexToNumber(data.slice(0, INDEX_BYTES * 2)),
+    } : null;
   }
 
   async getAll() {
-    return await this.redis.hgetall(this.name)
+    return await this.redis.hgetall(this.name).then(keys => {
+      return Object.entries(keys)
+        .map(([commit, data]) => 
+          [commit,
+          { 
+            memo: data.slice(INDEX_BYTES * 2),
+            index: hexToNumber(data.slice(0, INDEX_BYTES * 2)),
+          }] as [string, {memo: string, index: number}]
+        )
+      }
   }
 
   async removeAll() {

zp-relayer/utils/helpers.ts

@@ -8,7 +8,7 @@ import type { SnarkProof } from 'libzkbob-rs-node'
 import promiseRetry from 'promise-retry'
 import type Web3 from 'web3'
 import type { Contract } from 'web3-eth-contract'
-import { padLeft, toBN } from 'web3-utils'
+import { padLeft, toBN, numberToHex } from 'web3-utils'
 import { TxType } from 'zp-memo-parser'
 import { isContractCallError } from './web3Errors'
 
@@ -316,3 +316,11 @@ export async function fetchJson(serverUrl: string, path: string, query: [string,
 
   return await res.json()
 }
+
+export function numberToHexPadded(num: number, numBytes: number): string {
+  return padLeft(numberToHex(num).slice(2), numBytes * 2);
+}
+
+export function hexToNumber(hex: string): number {
+  return parseInt(hex, 16);
+}