grok-glance/scripts/gen-hooks.mjs

#!/usr/bin/env node
/**
 * Generate hooks/hooks.json from hooks/hooks.template.json.
 *
 * Runs as part of `npm run build`, and again on `glance sync-hooks`. Two jobs:
 *
 *   1. Make sure the /hook/* shared secret exists (mode 0600, in $GLANCE_HOME). The daemon
 *      requires it; without it the hook scripts are just anonymous POSTs, which is what this
 *      whole mechanism exists to stop.
 *   2. Substitute the placeholders the template declares, so values that are really derived
 *      from config.json - the approval hook's timeout above all - stop being hand-copied
 *      constants that drift.
 *
 * It also refuses to emit a hook that cannot work. An `http` handler pointed at a non-https
 * URL is the specific mistake that made every passive hook in this plugin a no-op for a
 * while: Grok Build's http runner puts every URL through SSRF validation and rejects any
 * other scheme outright (xai-grok-hooks/src/runner/http.rs, `validate_hook_url`).
 */

import fs from "node:fs";
import path from "node:path";
import { PLUGIN_ROOT, approvalHookTimeoutSecs, hookSecret, readConfig } from "../bin/glance-lib.mjs";

const TEMPLATE = path.join(PLUGIN_ROOT, "hooks", "hooks.template.json");
const OUTPUT = path.join(PLUGIN_ROOT, "hooks", "hooks.json");

const cfg = readConfig();
const token = hookSecret({ create: true });
if (!token) {
  console.error(`gen-hooks: could not create the hook secret in ${process.env.GLANCE_HOME ?? "~/.grok/glance"}`);
  process.exit(1);
}

const timeoutSecs = approvalHookTimeoutSecs(cfg);

let text = fs.readFileSync(TEMPLATE, "utf8");

// The quoted form first, so a JSON-valid template can carry a value that must end up numeric.
text = text
  .split(`"{{APPROVAL_TIMEOUT_SECS}}"`)
  .join(String(timeoutSecs))
  .split("{{APPROVAL_TIMEOUT_SECS}}")
  .join(String(timeoutSecs));

const embedsToken = text.includes("{{HOOK_TOKEN}}");
text = text.split("{{HOOK_TOKEN}}").join(token);

// Trust the emitted bytes, not the placeholder: a template that mentions the placeholder in a
// comment would otherwise ship the real secret in a world-readable file. (It did once.)
const tokenIsInOutput = text.includes(token);
if (tokenIsInOutput && !embedsToken) {
  console.error("gen-hooks: the hook secret leaked into hooks.json from somewhere unexpected");
  process.exit(1);
}

const leftover = text.match(/\{\{[A-Z_]+\}\}/);
if (leftover) {
  console.error(`gen-hooks: unknown placeholder ${leftover[0]} in hooks.template.json`);
  process.exit(1);
}

/* ------------------------------------------------------------------ validate */

let doc;
try {
  doc = JSON.parse(text);
} catch (err) {
  console.error(`gen-hooks: template did not produce valid JSON: ${err.message}`);
  process.exit(1);
}

const problems = [];
let handlers = 0;

for (const [event, groups] of Object.entries(doc.hooks ?? {})) {
  if (!Array.isArray(groups)) {
    problems.push(`${event}: expected an array of matcher groups`);
    continue;
  }
  for (const group of groups) {
    for (const h of group.hooks ?? []) {
      handlers++;
      const where = `${event} -> ${h.command ?? h.url ?? "(no target)"}`;
      if (h.type !== "command" && h.type !== "http") {
        problems.push(`${where}: type must be "command" or "http", got ${JSON.stringify(h.type)}`);
        continue;
      }
      if (typeof h.timeout !== "number" || !Number.isFinite(h.timeout) || h.timeout <= 0) {
        problems.push(`${where}: timeout must be a positive number of seconds`);
      }
      if (h.type === "http") {
        // The runner rejects every scheme but https, and treats RFC1918 / CGNAT / link-local
        // targets as SSRF. That rules out both loopback-over-http and Tailscale's 100.64/10.
        if (!/^https:\/\//.test(h.url ?? "")) {
          problems.push(
            `${where}: http handlers must use an https:// URL - Grok Build's SSRF check ` +
              `rejects anything else, so this hook would never fire`,
          );
        }
      } else {
        const script = /bin\/([A-Za-z0-9._-]+)/.exec(h.command ?? "");
        if (!script) {
          problems.push(`${where}: could not tell which script this command runs`);
        } else if (!fs.existsSync(path.join(PLUGIN_ROOT, "bin", script[1]))) {
          problems.push(`${where}: bin/${script[1]} does not exist`);
        }
      }
    }
  }
}

if (problems.length) {
  console.error("gen-hooks: refusing to write hooks.json\n");
  for (const p of problems) console.error(`  - ${p}`);
  process.exit(1);
}

/* --------------------------------------------------------------------- write */

const mode = tokenIsInOutput ? 0o600 : 0o644;
const previous = fs.existsSync(OUTPUT) ? fs.readFileSync(OUTPUT, "utf8") : null;

if (previous === text) {
  // Leave the mtime alone: a no-op build should not look like a change.
  fs.chmodSync(OUTPUT, mode);
  console.log(`hooks.json already current (${handlers} handlers, approval timeout ${timeoutSecs}s)`);
} else {
  fs.writeFileSync(OUTPUT, text, { mode });
  fs.chmodSync(OUTPUT, mode);
  console.log(
    `wrote hooks/hooks.json - ${handlers} handlers, approval timeout ${timeoutSecs}s` +
      (previous === null ? " (new file)" : ""),
  );
}

if (tokenIsInOutput) {
  console.warn(
    "gen-hooks: hooks.json now contains the hook secret (via the HOOK_TOKEN placeholder); it is " +
      "mode 0600 and must not be committed.",
  );
}