igalshilman

Effect Handlers in TypeScript

OCaml-style algebraic effects built on TypeScript generators. The fiber holds the iterator and a small state machine. The continuation is a one-shot, safety-checked handle. The handler is an async scheduler that drains synchronously-runnable work and parks while external wakers are pending.

Three pieces, each with one job:

• Fiber<T> — iteration state machine

igalshilman

restate-sdk-gen internals: fibers, the scheduler, and the stack

A walkthrough of how user generators, fibers, and the scheduler interact in @restatedev/restate-sdk-gen. Aimed at JS engineers who already know Restate and durable execution; we skip framing on journals/replay and focus on the runtime model.

Source files referenced throughout:

• src/scheduler.ts — orchestration

igalshilman

RocksDB SIGTRAP on Apple Silicon: Hardened libc++ vs Custom Aligned Allocators

Summary

RocksDB crashes with SIGTRAP (EXC_BREAKPOINT, brk #0x1) on Apple Silicon (aarch64-apple-darwin) when statistics are enabled. The crash occurs inside StatisticsImpl::recordTick or StatisticsImpl::recordInHistogram during normal database operations, including DB::Open.

The root cause is an incompatibility between Apple Clang's hardened libc++ bounds checking and RocksDB's custom cache-line-aligned allocator used by StatisticsData.

Symptoms

igalshilman

R = typing.TypeVar('R', bound=typing.Callable[..., typing.Awaitable[typing.Any]])
P = typing.ParamSpec('P'
def handler(func):
    func._is_handler = True
    return func


class Box:
    __slots__ = ('value',)

igalshilman

import {
  service,
  serve,
  type Context,
  RestatePromise,
  TerminalError,
} from "@restatedev/restate-sdk";

/***
 * A durable async generator that persists its state across restarts.

igalshilman

import {
  ObjectContext,
  Rand,
  service,
  TerminalError,
  type Context,
} from "@restatedev/restate-sdk";

class CircuitBreakerState {
  constructor(

igalshilman

from fastapi import FastAPI    
import restate    
    
app = FastAPI()    
    
@app.get("/")    
async def foo():    
    return { "foo" : "bar" }    
    
    

igalshilman

import { service, type Context } from "@restatedev/restate-sdk";

interface ServiceB {
  greet: (ctx: Context, name: string) => Promise<string>;
}

const realServiceB = service({
  name: "realServiceB",
  handlers: {

igalshilman

export type Subscriber = {
  service: string;
  handler: string;
  key?: string;
};

export const pubsub = restate.object({
  name: "pubsub",
  handlers: {
    /**

igalshilman

import * as restate from "@restatedev/restate-sdk";

export type WorkItem = {
  item: number; // compute item factorial
};

export type WorkRequest = {
  awekable: string;
};