microsoft/qdk
Publicmirrored from https://github.com/microsoft/qdkAvailable
source/npm/qsharp/src/workers/main.ts
343lines · modecode
| 1 | // Copyright (c) Microsoft Corporation. |
| 2 | // Licensed under the MIT License. |
| 3 | |
| 4 | import type { IQSharpError } from "../../lib/web/qsc_wasm.js"; |
| 5 | import type { CancellationToken } from "../cancellation.js"; |
| 6 | import { QdkDiagnostics } from "../diagnostics.js"; |
| 7 | import { log } from "../log.js"; |
| 8 | import type { |
| 9 | CommonEventMessage, |
| 10 | EventMessage, |
| 11 | IServiceEventMessage, |
| 12 | IServiceEventTarget, |
| 13 | IServiceProxy, |
| 14 | MethodMap, |
| 15 | RequestMessage, |
| 16 | ResponseMessage, |
| 17 | ServiceMethods, |
| 18 | ServiceProtocol, |
| 19 | ServiceState, |
| 20 | } from "./types.js"; |
| 21 | |
| 22 | /** |
| 23 | * Creates and initializes a service in a web worker, and returns a proxy for the service |
| 24 | * to be used from the main thread. |
| 25 | * |
| 26 | * @param workerArg The service web worker or the URL of the web worker script. |
| 27 | * @param wasmModule The wasm module to initialize the service with |
| 28 | * @param serviceProtocol An object that describes the service: its constructor, methods and events |
| 29 | * @param workerType The type of worker to create: "classic" for browsers, "module" for Node.js |
| 30 | * @returns A proxy object that implements the service interface. |
| 31 | * This interface can now be used as if calling into the real service, |
| 32 | * and the calls will be proxied to the web worker. |
| 33 | */ |
| 34 | export function createProxy< |
| 35 | TService extends ServiceMethods<TService>, |
| 36 | TServiceEventMsg extends IServiceEventMessage, |
| 37 | >( |
| 38 | workerArg: string | Worker, |
| 39 | wasmModule: WebAssembly.Module, |
| 40 | serviceProtocol: ServiceProtocol<TService, TServiceEventMsg>, |
| 41 | workerType: "classic" | "module", |
| 42 | ): TService & IServiceProxy { |
| 43 | // Create or use the WebWorker |
| 44 | const useModuleWorker: WorkerOptions = { type: workerType }; |
| 45 | |
| 46 | const worker = |
| 47 | typeof workerArg === "string" |
| 48 | ? new Worker(workerArg, useModuleWorker) |
| 49 | : workerArg; |
| 50 | |
| 51 | // Log any errors from the worker |
| 52 | worker.addEventListener("error", (ev: Event) => { |
| 53 | log.error("Worker error:", ev); |
| 54 | }); |
| 55 | |
| 56 | // Send it the Wasm module to instantiate |
| 57 | worker.postMessage({ |
| 58 | type: "init", |
| 59 | wasmModule, |
| 60 | qscLogLevel: log.getLogLevel(), |
| 61 | }); |
| 62 | |
| 63 | // If you lose the 'this' binding, some environments have issues |
| 64 | const postMessage = worker.postMessage.bind(worker); |
| 65 | const onTerminate = () => worker.terminate(); |
| 66 | |
| 67 | // Create the proxy which will forward method calls to the worker |
| 68 | const proxy = createProxyInternal<TService, TServiceEventMsg>( |
| 69 | postMessage, |
| 70 | onTerminate, |
| 71 | serviceProtocol.methods, |
| 72 | ); |
| 73 | |
| 74 | // Let proxy handle response and event messages from the worker |
| 75 | worker.addEventListener("message", (ev: MessageEvent) => { |
| 76 | proxy.onMsgFromWorker(ev.data); |
| 77 | }); |
| 78 | return proxy; |
| 79 | } |
| 80 | |
| 81 | /** Holds state for a single request received by the proxy */ |
| 82 | type RequestState< |
| 83 | TService extends ServiceMethods<TService>, |
| 84 | TServiceEventMsg extends IServiceEventMessage, |
| 85 | > = RequestMessage<TService> & { |
| 86 | resolve: (val: any) => void; |
| 87 | reject: (err: any) => void; |
| 88 | requestEventTarget?: IServiceEventTarget<TServiceEventMsg>; |
| 89 | cancellationToken?: CancellationToken; |
| 90 | }; |
| 91 | |
| 92 | /* |
| 93 | The WorkerProxy works by queuing up requests to send over to the Worker, only |
| 94 | ever having one in flight at a time. By queuing on the caller side, this allows |
| 95 | for cancellation (it checks if a request is cancelled before sending to the worker). |
| 96 | |
| 97 | The queue contains an entry for each request with the data to send, the promise |
| 98 | to resolve, the event handler, and the cancellation token. When a request completes |
| 99 | the next one (if present) is fetched from the queue. If it is marked as cancelled, |
| 100 | it is resolved immediately, else it is marked as the current request and the command |
| 101 | sent to the worker. As events occurs on the current request the event handler is |
| 102 | invoked. When the response is received this is used to resolve the promise and |
| 103 | complete the request. |
| 104 | */ |
| 105 | |
| 106 | /** |
| 107 | * Function to create the proxy for a type. To be used from the main thread. |
| 108 | * |
| 109 | * @param postMessage A function to post messages to the worker |
| 110 | * @param terminator A function to call to tear down the worker thread |
| 111 | * @param methods A map of method names to be proxied and some metadata @see MethodMap |
| 112 | * @returns The proxy object. The caller should then set the onMsgFromWorker |
| 113 | * property to a callback that will receive messages from the worker. |
| 114 | */ |
| 115 | function createProxyInternal< |
| 116 | TService extends ServiceMethods<TService>, |
| 117 | TServiceEventMsg extends IServiceEventMessage, |
| 118 | >( |
| 119 | postMessage: (msg: RequestMessage<TService>) => void, |
| 120 | terminator: () => void, |
| 121 | methods: MethodMap<TService>, |
| 122 | ): TService & |
| 123 | IServiceProxy & { |
| 124 | onMsgFromWorker: ( |
| 125 | msg: ResponseMessage<TService> | EventMessage<TServiceEventMsg>, |
| 126 | ) => void; |
| 127 | } { |
| 128 | const queue: RequestState<TService, TServiceEventMsg>[] = []; |
| 129 | const eventTarget = new EventTarget(); |
| 130 | let curr: RequestState<TService, TServiceEventMsg> | undefined; |
| 131 | let state: ServiceState = "idle"; |
| 132 | |
| 133 | function setState(newState: ServiceState) { |
| 134 | if (state === newState) return; |
| 135 | state = newState; |
| 136 | if (proxy.onstatechange) proxy.onstatechange(state); |
| 137 | } |
| 138 | |
| 139 | type ResultOf<TRespMsg> = TRespMsg extends { result: infer R } ? R : never; |
| 140 | |
| 141 | function queueRequest( |
| 142 | msg: RequestMessage<TService>, |
| 143 | requestEventTarget?: IServiceEventTarget<TServiceEventMsg>, |
| 144 | cancellationToken?: CancellationToken, |
| 145 | ): Promise<ResultOf<ResponseMessage<TService>>> { |
| 146 | return new Promise((resolve, reject) => { |
| 147 | queue.push({ |
| 148 | type: msg.type, |
| 149 | args: msg.args, |
| 150 | resolve, |
| 151 | reject, |
| 152 | requestEventTarget, |
| 153 | cancellationToken, |
| 154 | } as RequestState<TService, TServiceEventMsg>); |
| 155 | |
| 156 | // If nothing was running when this got added, kick off processing |
| 157 | if (queue.length === 1) doNextRequest(); |
| 158 | }); |
| 159 | } |
| 160 | |
| 161 | function doNextRequest() { |
| 162 | if (curr) return; |
| 163 | |
| 164 | while ((curr = queue.shift())) { |
| 165 | if (curr.cancellationToken?.isCancellationRequested) { |
| 166 | curr.reject("cancelled"); |
| 167 | continue; |
| 168 | } else { |
| 169 | break; |
| 170 | } |
| 171 | } |
| 172 | if (!curr) { |
| 173 | // Nothing else queued, signal that we're now idle and exit. |
| 174 | log.trace("Proxy: Worker queue is empty"); |
| 175 | setState("idle"); |
| 176 | return; |
| 177 | } |
| 178 | |
| 179 | const msg = { type: curr.type, args: curr.args }; |
| 180 | if (methods[curr.type] === "requestWithProgress") { |
| 181 | setState("busy"); |
| 182 | } |
| 183 | |
| 184 | log.trace("Proxy: Posting message to worker: %o", msg); |
| 185 | postMessage(msg); |
| 186 | } |
| 187 | |
| 188 | function onMsgFromWorker( |
| 189 | msg: |
| 190 | | ResponseMessage<TService> |
| 191 | | EventMessage<TServiceEventMsg> |
| 192 | | CommonEventMessage, |
| 193 | ) { |
| 194 | if (log.getLogLevel() >= 4) |
| 195 | log.trace("Proxy: Received message from worker: %s", JSON.stringify(msg)); |
| 196 | |
| 197 | if (msg.messageType === "common-event") { |
| 198 | const commonEvent = msg; // assignment is necessary here for TypeScript to narrow the type |
| 199 | switch (commonEvent.type) { |
| 200 | case "telemetry-event": |
| 201 | { |
| 202 | const detail = commonEvent.detail; |
| 203 | log.logTelemetry(detail); |
| 204 | } |
| 205 | break; |
| 206 | case "log": |
| 207 | { |
| 208 | const detail = commonEvent.detail; |
| 209 | log.logWithLevel(detail.level, detail.target, ...detail.data); |
| 210 | } |
| 211 | break; |
| 212 | } |
| 213 | } else if (msg.messageType === "event") { |
| 214 | const event = new Event(msg.type) as Event & TServiceEventMsg; |
| 215 | event.detail = msg.detail; |
| 216 | |
| 217 | log.trace("Proxy: Posting event: %o", msg); |
| 218 | // Post to a currently attached event target if there's a "requestWithProgress" |
| 219 | // in progress |
| 220 | curr?.requestEventTarget?.dispatchEvent(event); |
| 221 | // Also post to the general event target |
| 222 | eventTarget.dispatchEvent(event); |
| 223 | } else if (msg.messageType === "response") { |
| 224 | if (!curr) { |
| 225 | log.error("Proxy: No active request when message received: %o", msg); |
| 226 | return; |
| 227 | } |
| 228 | const result = { |
| 229 | success: msg.result.success, |
| 230 | data: msg.result.success ? msg.result.result : msg.result.error, |
| 231 | }; |
| 232 | if (result.success) { |
| 233 | curr.resolve(result.data); |
| 234 | curr = undefined; |
| 235 | doNextRequest(); |
| 236 | } else { |
| 237 | let err = result.data; |
| 238 | |
| 239 | // The error may be a serialized error object. |
| 240 | err = deserializeIfError(err); |
| 241 | |
| 242 | curr.reject(err); |
| 243 | curr = undefined; |
| 244 | doNextRequest(); |
| 245 | } |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | // Create the proxy object to be returned |
| 250 | const proxy = {} as TService & |
| 251 | IServiceProxy & { onMsgFromWorker: typeof onMsgFromWorker }; |
| 252 | |
| 253 | // Assign each method with the desired proxying behavior |
| 254 | for (const methodName of Object.keys(methods) as (keyof TService & |
| 255 | string)[]) { |
| 256 | // @ts-expect-error - tricky to derive the type of the actual method here |
| 257 | proxy[methodName] = (...args: any[]) => { |
| 258 | let requestEventTarget: |
| 259 | | IServiceEventTarget<TServiceEventMsg> |
| 260 | | undefined = undefined; |
| 261 | |
| 262 | switch (methods[methodName]) { |
| 263 | case "addEventListener": |
| 264 | { |
| 265 | // @ts-expect-error - can't get the typing of the rest parameters quite right |
| 266 | eventTarget.addEventListener(...args); |
| 267 | } |
| 268 | break; |
| 269 | case "removeEventListener": |
| 270 | { |
| 271 | // @ts-expect-error - can't get the typing of the rest parameters quite right |
| 272 | eventTarget.removeEventListener(...args); |
| 273 | } |
| 274 | break; |
| 275 | case "requestWithProgress": { |
| 276 | // For progress methods, the last argument is the event target |
| 277 | requestEventTarget = args[args.length - 1]; |
| 278 | args = args.slice(0, args.length - 1); |
| 279 | } |
| 280 | // fallthrough |
| 281 | case "request": { |
| 282 | return queueRequest( |
| 283 | { type: methodName, args } as RequestMessage<TService>, |
| 284 | requestEventTarget, |
| 285 | ); |
| 286 | } |
| 287 | } |
| 288 | }; |
| 289 | } |
| 290 | |
| 291 | proxy.onstatechange = null; |
| 292 | proxy.terminate = () => { |
| 293 | // Kill the worker without a chance to shutdown. May be needed if it is not responding. |
| 294 | log.info("Proxy: Terminating the worker"); |
| 295 | if (curr) { |
| 296 | log.trace( |
| 297 | "Proxy: Terminating running worker item of type: %s", |
| 298 | curr.type, |
| 299 | ); |
| 300 | curr.reject("terminated"); |
| 301 | } |
| 302 | // Reject any outstanding items |
| 303 | while (queue.length) { |
| 304 | const item = queue.shift(); |
| 305 | log.trace( |
| 306 | "Proxy: Terminating outstanding work item of type: %s", |
| 307 | item?.type, |
| 308 | ); |
| 309 | item?.reject("terminated"); |
| 310 | } |
| 311 | terminator(); |
| 312 | }; |
| 313 | proxy.onMsgFromWorker = onMsgFromWorker; |
| 314 | |
| 315 | return proxy; |
| 316 | } |
| 317 | |
| 318 | /** |
| 319 | * Deserializes an error if it is a known type. |
| 320 | * |
| 321 | * By default, browsers can only send certain types of errors between the main thread and a worker. |
| 322 | * See: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#error_types |
| 323 | * |
| 324 | * Serializing our own custom errors allows us to send them between threads. |
| 325 | */ |
| 326 | function deserializeIfError(err: unknown) { |
| 327 | if (err !== null && typeof err === "object" && "name" in err) { |
| 328 | if (err.name === "QdkDiagnostics" && "data" in err) { |
| 329 | err = new QdkDiagnostics(err.data as IQSharpError[]); |
| 330 | } else if ( |
| 331 | err.name === "WebAssembly.RuntimeError" && |
| 332 | "message" in err && |
| 333 | (typeof err.message === "string" || typeof err.message === "undefined") && |
| 334 | "stack" in err && |
| 335 | (typeof err.stack === "string" || typeof err.stack === "undefined") |
| 336 | ) { |
| 337 | const newErr = new WebAssembly.RuntimeError(err.message); |
| 338 | newErr.stack = err.stack; |
| 339 | err = newErr; |
| 340 | } |
| 341 | } |
| 342 | return err; |
| 343 | } |
| 344 | |