feat(block-logs-stream): add block logs stream package

.changeset/nasty-waves-divide.md

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+---
+"@latticexyz/block-logs-stream": minor
+---
+
+Add block logs stream package
+
+```ts
+import { filter, map, mergeMap } from "rxjs";
+import { createPublicClient, parseAbi } from "viem";
+import {
+  createBlockStream,
+  isNonPendingBlock,
+  groupLogsByBlockNumber,
+  blockRangeToLogs,
+} from "@latticexyz/block-logs-stream";
+
+const publicClient = createPublicClient({
+  // your viem public client config here
+});
+
+const latestBlock$ = await createBlockStream({ publicClient, blockTag: "latest" });
+
+const latestBlockNumber$ = latestBlock$.pipe(
+  filter(isNonPendingBlock),
+  map((block) => block.number)
+);
+
+latestBlockNumber$
+  .pipe(
+    map((latestBlockNumber) => ({ startBlock: 0n, endBlock: latestBlockNumber })),
+    blockRangeToLogs({
+      publicClient,
+      address,
+      events: parseAbi([
+        "event StoreDeleteRecord(bytes32 table, bytes32[] key)",
+        "event StoreSetField(bytes32 table, bytes32[] key, uint8 schemaIndex, bytes data)",
+        "event StoreSetRecord(bytes32 table, bytes32[] key, bytes data)",
+        "event StoreEphemeralRecord(bytes32 table, bytes32[] key, bytes data)",
+      ]),
+    }),
+    mergeMap(({ logs }) => from(groupLogsByBlockNumber(logs)))
+  )
+  .subscribe((block) => {
+    console.log("got events for block", block);
+  });
+```

packages/block-logs-stream/.eslintrc

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+{
+  "extends": ["../../.eslintrc"],
+  "rules": {
+    "@typescript-eslint/explicit-function-return-type": "error"
+  }
+}

packages/block-logs-stream/.gitignore

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+dist

packages/block-logs-stream/.npmignore

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+*
+
+!dist/**
+!src/**
+!package.json
+!README.md

packages/block-logs-stream/README.md

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+# Block logs stream
+
+A set of utilities for efficiently retrieving blockchain event logs. Built on top of [viem][0] and [RxJS][1].
+
+[0]: https://viem.sh/
+[1]: https://rxjs.dev/
+
+## Example
+
+```ts
+import { filter, map, mergeMap } from "rxjs";
+import { createPublicClient, parseAbi } from "viem";
+import {
+  createBlockStream,
+  isNonPendingBlock,
+  groupLogsByBlockNumber,
+  blockRangeToLogs,
+} from "@latticexyz/block-logs-stream";
+
+const publicClient = createPublicClient({
+  // your viem public client config here
+});
+
+const latestBlock$ = await createBlockStream({ publicClient, blockTag: "latest" });
+
+const latestBlockNumber$ = latestBlock$.pipe(
+  filter(isNonPendingBlock),
+  map((block) => block.number)
+);
+
+latestBlockNumber$
+  .pipe(
+    map((latestBlockNumber) => ({ startBlock: 0n, endBlock: latestBlockNumber })),
+    blockRangeToLogs({
+      publicClient,
+      address,
+      events: parseAbi([
+        "event StoreDeleteRecord(bytes32 table, bytes32[] key)",
+        "event StoreSetField(bytes32 table, bytes32[] key, uint8 schemaIndex, bytes data)",
+        "event StoreSetRecord(bytes32 table, bytes32[] key, bytes data)",
+        "event StoreEphemeralRecord(bytes32 table, bytes32[] key, bytes data)",
+      ]),
+    }),
+    mergeMap(({ logs }) => from(groupLogsByBlockNumber(logs)))
+  )
+  .subscribe((block) => {
+    console.log("got events for block", block);
+  });
+```

packages/block-logs-stream/package.json

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+{
+  "name": "@latticexyz/block-logs-stream",
+  "version": "1.42.0",
+  "description": "Create a stream of EVM block logs for events",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/latticexyz/mud.git",
+    "directory": "packages/block-logs-stream"
+  },
+  "license": "MIT",
+  "type": "module",
+  "exports": {
+    ".": "./dist/index.js"
+  },
+  "types": "src/index.ts",
+  "scripts": {
+    "build": "pnpm run build:js",
+    "build:js": "tsup",
+    "clean": "pnpm run clean:js",
+    "clean:js": "rimraf dist",
+    "dev": "tsup --watch",
+    "lint": "eslint .",
+    "test": "vitest typecheck --run --passWithNoTests && vitest --run --passWithNoTests"
+  },
+  "dependencies": {
+    "@latticexyz/common": "workspace:*",
+    "@latticexyz/config": "workspace:*",
+    "@latticexyz/schema-type": "workspace:*",
+    "abitype": "0.8.7",
+    "debug": "^4.3.4",
+    "rxjs": "7.5.5",
+    "viem": "1.1.7"
+  },
+  "devDependencies": {
+    "@types/debug": "^4.1.7",
+    "tsup": "^6.7.0",
+    "vitest": "0.31.4"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "gitHead": "914a1e0ae4a573d685841ca2ea921435057deb8f"
+}

packages/block-logs-stream/src/blockRangeToLogs.test.ts

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+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { blockRangeToLogs } from "./blockRangeToLogs";
+import { Subject, lastValueFrom, map, toArray } from "rxjs";
+import { EIP1193RequestFn, RpcLog, Transport, createPublicClient, createTransport } from "viem";
+import { wait } from "./utils";
+
+// TODO: there is a chance that these tests will need to be written differently with timers to avoid flakiness
+
+const mockedTransportRequest = vi.fn<Parameters<EIP1193RequestFn>, ReturnType<EIP1193RequestFn>>();
+const mockTransport: Transport = () =>
+  createTransport({
+    key: "mock",
+    name: "Mock Transport",
+    request: mockedTransportRequest as any,
+    type: "mock",
+  });
+
+const publicClient = createPublicClient({
+  transport: mockTransport,
+});
+
+describe("blockRangeToLogs", () => {
+  beforeEach(() => {
+    mockedTransportRequest.mockClear();
+  });
+
+  it("processes block ranges in order", async () => {
+    const requests: any[] = [];
+    mockedTransportRequest.mockImplementation(async ({ method, params }): Promise<RpcLog[]> => {
+      requests.push(params);
+      if (method !== "eth_getLogs") throw new Error("not implemented");
+      await wait(450);
+      return [];
+    });
+
+    const latestBlockNumber$ = new Subject<bigint>();
+
+    const logs$ = latestBlockNumber$.pipe(
+      map((endBlock) => ({ startBlock: 0n, endBlock })),
+      blockRangeToLogs({
+        publicClient,
+        address: "0x",
+        events: [],
+      })
+    );
+
+    (async (): Promise<void> => {
+      for (let blockNumber = 1000n; blockNumber <= 1010n; blockNumber++) {
+        await wait(100);
+        latestBlockNumber$.next(blockNumber);
+      }
+      await wait(100);
+      latestBlockNumber$.complete();
+    })();
+
+    const results = await lastValueFrom(logs$.pipe(toArray()));
+
+    expect(requests).toMatchInlineSnapshot(`
+      [
+        [
+          {
+            "address": "0x",
+            "fromBlock": "0x0",
+            "toBlock": "0x3e8",
+            "topics": [
+              [],
+            ],
+          },
+        ],
+        [
+          {
+            "address": "0x",
+            "fromBlock": "0x3e9",
+            "toBlock": "0x3ec",
+            "topics": [
+              [],
+            ],
+          },
+        ],
+        [
+          {
+            "address": "0x",
+            "fromBlock": "0x3ed",
+            "toBlock": "0x3f0",
+            "topics": [
+              [],
+            ],
+          },
+        ],
+        [
+          {
+            "address": "0x",
+            "fromBlock": "0x3f1",
+            "toBlock": "0x3f2",
+            "topics": [
+              [],
+            ],
+          },
+        ],
+      ]
+    `);
+
+    expect(results).toMatchInlineSnapshot(`
+      [
+        {
+          "fromBlock": 0n,
+          "logs": [],
+          "toBlock": 1000n,
+        },
+        {
+          "fromBlock": 1001n,
+          "logs": [],
+          "toBlock": 1004n,
+        },
+        {
+          "fromBlock": 1005n,
+          "logs": [],
+          "toBlock": 1008n,
+        },
+        {
+          "fromBlock": 1009n,
+          "logs": [],
+          "toBlock": 1010n,
+        },
+      ]
+    `);
+  });
+});

packages/block-logs-stream/src/blockRangeToLogs.ts

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+import { EMPTY, OperatorFunction, concatMap, from, pipe, tap } from "rxjs";
+import { FetchLogsResult, fetchLogs } from "./fetchLogs";
+import { AbiEvent, Address } from "abitype";
+import { BlockNumber, PublicClient } from "viem";
+
+export type BlockRangeToLogsOptions<TAbiEvents extends readonly AbiEvent[]> = {
+  /**
+   * [viem `PublicClient`][0] used for fetching logs from the RPC.
+   *
+   * [0]: https://viem.sh/docs/clients/public.html
+   */
+  publicClient: PublicClient;
+  /**
+   * Optional contract address(es) to fetch logs for.
+   */
+  address?: Address | Address[];
+  /**
+   * Events to fetch logs for.
+   */
+  events: TAbiEvents;
+  /**
+   * Optional maximum block range, if your RPC limits the amount of blocks fetched at a time.
+   */
+  maxBlockRange?: bigint;
+};
+
+export type BlockRangeToLogsResult<TAbiEvents extends readonly AbiEvent[]> = OperatorFunction<
+  { startBlock: BlockNumber; endBlock: BlockNumber },
+  FetchLogsResult<TAbiEvents>
+>;
+
+/**
+ * Takes in an observable of `Observable<{ startBlock: bigint, endBlock: bigint }>` and uses a viem `publicClient` to get logs for the contract `address` and matching `events` and emits the logs as they are fetched.
+ *
+ * @param {BlockRangeToLogsOptions<AbiEvent[]>} options See `BlockRangeToLogsOptions`.
+ * @returns {BlockRangeToLogsResult<AbiEvent[]>} An operator function that transforms a stream of block ranges into a stream of fetched logs.
+ */
+export function blockRangeToLogs<TAbiEvents extends readonly AbiEvent[]>({
+  publicClient,
+  address,
+  events,
+  maxBlockRange,
+}: BlockRangeToLogsOptions<TAbiEvents>): BlockRangeToLogsResult<TAbiEvents> {
+  let fromBlock: bigint;
+  let toBlock: bigint;
+
+  return pipe(
+    tap(({ endBlock, startBlock }) => {
+      fromBlock ??= startBlock;
+      toBlock = endBlock;
+    }),
+    // concatMap only processes the next emission once the inner observable completes,
+    // so it always uses the latest`toBlock` value.
+    concatMap(() => {
+      if (fromBlock > toBlock) return EMPTY;
+      return from(
+        fetchLogs({
+          publicClient,
+          address,
+          events,
+          fromBlock,
+          toBlock,
+          maxBlockRange,
+        })
+      ).pipe(
+        tap(({ toBlock }) => {
+          fromBlock = toBlock + 1n;
+        })
+      );
+    })
+  );
+}

packages/block-logs-stream/src/createBlockStream.ts

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+import { Observable } from "rxjs";
+import type { Block, BlockTag, PublicClient } from "viem";
+
+export type CreateBlockStreamOptions = {
+  publicClient: PublicClient;
+  blockTag: BlockTag;
+};
+
+export type CreateBlockStreamResult = Observable<Block>;
+
+export function createBlockStream({ publicClient, blockTag }: CreateBlockStreamOptions): CreateBlockStreamResult {
+  return new Observable(function subscribe(subscriber) {
+    return publicClient.watchBlocks({
+      blockTag,
+      emitOnBegin: true,
+      onBlock: (block) => subscriber.next(block),
+      onError: (error) => subscriber.error(error),
+    });
+  });
+}

packages/block-logs-stream/src/debug.ts

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+import createDebug from "debug";
+
+export const debug = createDebug("mud:block-events-stream");