feat: Add native execution environment

Author: FrederikBolding

packages/snaps-controllers/package.json

@@ -138,6 +138,7 @@
     "lodash": "^4.17.21",
     "prettier": "^3.3.3",
     "rimraf": "^4.1.2",
+    "ses": "^1.14.0",
     "ts-node": "^10.9.1",
     "tsx": "^4.20.3",
     "typescript": "~5.3.3",

packages/snaps-controllers/src/services/native/NativeExecutionService.test.browser.ts

@@ -0,0 +1,39 @@
+// eslint-disable-next-line import-x/no-unassigned-import
+import 'ses';
+import { HandlerType } from '@metamask/snaps-utils';
+import { MOCK_SNAP_ID } from '@metamask/snaps-utils/test-utils';
+import { describe, expect, it } from 'vitest';
+
+import { NativeExecutionService } from './NativeExecutionService';
+import { METAMASK_ORIGIN } from '../../snaps';
+import { createService } from '../../test-utils/service';
+
+lockdown({
+  domainTaming: 'unsafe',
+  errorTaming: 'unsafe',
+  stackFiltering: 'verbose',
+  overrideTaming: 'severe',
+  errorTrapping: 'none',
+});
+
+describe('NativeExecutionService', () => {
+  it('works', async () => {
+    const { service } = createService(NativeExecutionService);
+
+    await service.executeSnap({
+      snapId: MOCK_SNAP_ID,
+      sourceCode: `module.exports.onRpcRequest = () => { console.log('foo'); return 'bar'; }`,
+      endowments: ['console'],
+    });
+
+    const result = await service.handleRpcRequest(MOCK_SNAP_ID, {
+      origin: METAMASK_ORIGIN,
+      request: {
+        method: 'foo',
+      },
+      handler: HandlerType.OnRpcRequest,
+    });
+
+    expect(result).toBe('bar');
+  });
+});

packages/snaps-controllers/src/services/native/NativeExecutionService.ts

@@ -0,0 +1,48 @@
+import type { BasePostMessageStream } from '@metamask/post-message-stream';
+import { NativeSnapExecutor } from '@metamask/snaps-execution-environments';
+import type { Json } from '@metamask/utils';
+import { Duplex } from 'readable-stream';
+
+import {
+  AbstractExecutionService,
+  type TerminateJobArgs,
+} from '../AbstractExecutionService';
+
+export class NativeExecutionService extends AbstractExecutionService<NativeSnapExecutor> {
+  protected terminateJob(_job: TerminateJobArgs<NativeSnapExecutor>): void {
+    // no-op
+  }
+
+  protected async initEnvStream(
+    _snapId: string,
+  ): Promise<{ worker: NativeSnapExecutor; stream: BasePostMessageStream }> {
+    // TODO: Sanity check this.
+    const workerStream = new Duplex({
+      objectMode: true,
+      read() {
+        return undefined;
+      },
+      write(chunk: Json, encoding: BufferEncoding, callback) {
+        // eslint-disable-next-line @typescript-eslint/no-use-before-define
+        stream.push(chunk, encoding);
+        callback();
+      },
+    });
+    const stream = new Duplex({
+      objectMode: true,
+      read() {
+        return undefined;
+      },
+      write(chunk: Json, encoding: BufferEncoding, callback) {
+        workerStream.push(chunk, encoding);
+        callback();
+      },
+    }) as unknown as BasePostMessageStream;
+
+    // NOTE: Initializes a Snap executor that runs in the same JS thread as the execution service.
+    // Does not provide process isolation.
+    const worker = NativeSnapExecutor.initialize(workerStream);
+
+    return Promise.resolve({ worker, stream });
+  }
+}

packages/snaps-execution-environments/src/index.ts

@@ -1 +1,2 @@
 export * from './proxy';
+export * from './native';

packages/snaps-execution-environments/src/native/NativeSnapExecutor.ts

@@ -0,0 +1,23 @@
+import ObjectMultiplex from '@metamask/object-multiplex';
+import { logError, SNAP_STREAM_NAMES } from '@metamask/snaps-utils';
+import type { Duplex } from 'readable-stream';
+import { pipeline } from 'readable-stream';
+
+import { BaseSnapExecutor } from '../common/BaseSnapExecutor';
+
+export class NativeSnapExecutor extends BaseSnapExecutor {
+  static initialize(stream: Duplex) {
+    const mux = new ObjectMultiplex();
+    pipeline(stream, mux, stream, (error) => {
+      if (error) {
+        logError(`Parent stream failure, closing worker.`, error);
+      }
+      self.close();
+    });
+
+    const commandStream = mux.createStream(SNAP_STREAM_NAMES.COMMAND);
+    const rpcStream = mux.createStream(SNAP_STREAM_NAMES.JSON_RPC);
+
+    return new NativeSnapExecutor(commandStream, rpcStream);
+  }
+}

packages/snaps-execution-environments/src/native/index.ts

@@ -0,0 +1 @@
+export * from './NativeSnapExecutor';

yarn.lock

@@ -4311,6 +4311,7 @@ __metadata:
     readable-web-to-node-stream: "npm:^3.0.2"
     rimraf: "npm:^4.1.2"
     semver: "npm:^7.5.4"
+    ses: "npm:^1.14.0"
     tar-stream: "npm:^3.1.7"
     ts-node: "npm:^10.9.1"
     tsx: "npm:^4.20.3"