Added prototype files.

make_cred.mjs

@@ -0,0 +1,29 @@
+#!/usr/bin/env node
+import { readFileSync, writeFileSync } from "node:fs";
+import { parseArgs } from "node:util";
+
+const { values } = parseArgs({
+  options: {
+    "private-key-file": { type: "string" },
+    "client-email": { type: "string" },
+    output: { type: "string", default: "cred.json" },
+  },
+});
+
+if (!values["private-key-file"] || !values["client-email"]) {
+  console.error("Usage: make_cred.mjs --private-key-file FILE --client-email EMAIL [--output FILE]");
+  process.exit(1);
+}
+
+const privateKey = readFileSync(values["private-key-file"], "utf8");
+const clientEmail = values["client-email"];
+
+const cred = {
+  type: "service_account",
+  project_id: clientEmail.split("@")[1].split(".")[0],
+  private_key: privateKey,
+  client_email: clientEmail,
+  token_uri: "https://oauth2.googleapis.com/token",
+};
+
+writeFileSync(values.output, JSON.stringify(cred, null, 2) + "\n");