// TODO cleanup exec usages once spawn is ready
import { spawn, SpawnOptions } from "child_process";
import { ObjectEncodingOptions } from "fs";
export type SpawnResult = {
// this is basically ExecException except I want my own type for it...
// b/c I want this to represent all results
// ... by the way throws put stdout/stderr on the error "result" object
// hence I am replicating that here and in my promise reject calls
stdout: string;
stderr: string;
code?: number;
signal?: NodeJS.Signals | undefined;
};
export type SpawnFailure = SpawnResult & {
// ONLY on errors:
message?: string; // FYI redundant b/c message ~= `Command failed: ${cmd}\n${stderr}\n`
killed?: boolean;
cmd?: string; // FYI redundant
};
export async function spawn_wrapped(
command: string,
args: string[],
stdin: string | undefined,
options: SpawnOptions
): Promise<SpawnResult | SpawnFailure> {
return new Promise((resolve, reject) => {
if (!stdin) {
// FYI default is all 'pipe' (works when stdin is provided)
// 'ignore' attaches /dev/null
// order: [STDIN, STDOUT, STDERR]
options.stdio = ['ignore', 'pipe', 'pipe'];
// ? I wonder if this was related to fishWorkaround issue w/ STDIN (see commit history)... I was using base64 encoding to pass STDIN
}
const child = spawn(command, args, options);
// PRN return pid to callers?
// console.log(`child.pid: ${child.pid}`);
let stdout = ""
let stderr = ""
if (child.stdin && stdin) {
child.stdin.write(stdin);
child.stdin.end();
}
if (child.stdout) {
child.stdout.on("data", (chunk: Buffer | string) => {
stdout += chunk.toString();
});
}
if (child.stderr) {
child.stderr.on("data", (chunk: Buffer | string) => {
stderr += chunk.toString();
});
}
let errored = false;
child.on("error", (err: Error) => {
// ChildProcess 'error' docs: https://nodejs.org/api/child_process.html#event-error
// error running process
// IIUC not just b/c of command failed w/ non-zero exit code
const result: SpawnFailure = {
stdout: stdout,
stderr: stderr,
//
code: (err as any).code,
signal: (err as any).signal,
//
message: err.message,
// killed: (err as any).killed,
cmd: command, // TODO does error have .cmd on it? is it the composite result of processing in spawn too? (or same as I passed)
};
// console.log("ON_ERROR", result);
errored = true;
reject(result);
});
child.on("close", (code: number | null, signal: NodeJS.Signals | null) => {
// ChildProcess 'close' docs: https://nodejs.org/api/child_process.html#event-close
// 'close' is after child process ends AND stdio streams are closed
// - after 'exit' or 'error'
//
// * do not resolve if 'error' already called (promise is already resolved)
if (errored) return;
// either code is set, or signal, but NOT BOTH
// signal if process killed
// FYI close does not mean code==0
const result: SpawnResult = {
stdout: stdout,
stderr: stderr,
code: code ?? undefined,
signal: signal ?? undefined,
};
// console.log("ON_CLOSE", result);
resolve(result);
});
});
}
