feat: filtering public logs by tag

yarn-project/archiver/src/store/kv_archiver_store.test.ts

@@ -2782,6 +2782,24 @@ describe('KVArchiverDataStore', () => {
       }
     });
 
+    it('"tag" filter param is respected', async () => {
+      // Get a random tag from the logs
+      const targetBlockIndex = randomInt(numBlocksForPublicLogs);
+      const targetBlock = publishedCheckpoints[targetBlockIndex].checkpoint.blocks[0];
+      const targetTxIndex = randomInt(getTxsPerBlock(targetBlock));
+      const targetLogIndex = randomInt(getPublicLogsPerTx(targetBlock, targetTxIndex));
+      const targetTag = targetBlock.body.txEffects[targetTxIndex].publicLogs[targetLogIndex].fields[0];
+
+      const response = await store.getPublicLogs({ tag: targetTag });
+
+      expect(response.maxLogsHit).toBeFalsy();
+      expect(response.logs.length).toBeGreaterThan(0);
+
+      for (const extendedLog of response.logs) {
+        expect(extendedLog.log.fields[0].equals(targetTag)).toBeTruthy();
+      }
+    });
+
     it('"afterLog" filter param is respected', async () => {
       // Get a random log as reference
       const targetBlockIndex = randomInt(numBlocksForPublicLogs);

yarn-project/archiver/src/store/log_store.ts

@@ -592,7 +592,10 @@ export class LogStore {
     let logIndex = typeof filter.afterLog?.logIndex === 'number' ? filter.afterLog.logIndex + 1 : 0;
     for (; logIndex < txLogs.length; logIndex++) {
       const log = txLogs[logIndex];
-      if (!filter.contractAddress || log.contractAddress.equals(filter.contractAddress)) {
+      if (
+        (!filter.contractAddress || log.contractAddress.equals(filter.contractAddress)) &&
+        (!filter.tag || log.fields[0]?.equals(filter.tag))
+      ) {
         results.push(
           new ExtendedPublicLog(new LogId(BlockNumber(blockNumber), blockHash, txHash, txIndex, logIndex), log),
         );

yarn-project/stdlib/src/logs/log_filter.ts

@@ -1,3 +1,5 @@
+import type { Fr } from '@aztec/foundation/curves/bn254';
+
 import { z } from 'zod';
 
 import type { AztecAddress } from '../aztec-address/index.js';
@@ -20,6 +22,8 @@ export type LogFilter = {
   afterLog?: LogId;
   /** The contract address to filter logs by. */
   contractAddress?: AztecAddress;
+  /** The tag (first field of the log) to filter logs by. */
+  tag?: Fr;
 };
 
 export const LogFilterSchema: ZodFor<LogFilter> = z.object({
@@ -28,4 +32,5 @@ export const LogFilterSchema: ZodFor<LogFilter> = z.object({
   toBlock: schemas.Integer.optional(),
   afterLog: LogId.schema.optional(),
   contractAddress: schemas.AztecAddress.optional(),
+  tag: schemas.Fr.optional(),
 });