Initial import of zappier-customer-service from zapier monorepo

src/nats-billing.js

@@ -0,0 +1,44 @@
+export const SUBJECTS = {
+  STATEMENT_GET: 'verae.billing.statement.get',
+  BALANCE_ADJUST: 'verae.billing.balance.adjust',
+  AUTHZ_CHECK: 'verae.access.authz.check',
+};
+const PLANE = 'staff';
+
+async function authz(subject, payload) {
+  const http = process.env.AUTHZ_URL;
+  if (!http && !process.env.NATS_URL) return { allow: true, subject };
+  if (http) {
+    const r = await fetch(`${http.replace(/\/$/, '')}/check`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({ plane: PLANE, subject, kind: payload?.kind, payload, principal: payload?.agent }),
+    });
+    return r.json();
+  }
+  return { allow: true, subject };
+}
+
+export async function billingRequest(subject, payload) {
+  const decision = await authz(subject, payload);
+  if (decision && decision.allow === false) {
+    const err = new Error(decision.reason || 'denied');
+    err.status = 403;
+    err.decision = decision;
+    throw err;
+  }
+  const url = process.env.NATS_URL;
+  if (!url) return null;
+  try {
+    const { connect, StringCodec } = await import('nats');
+    const nc = await connect({ servers: url.split(','), name: 'zappier-customer-service' });
+    const sc = StringCodec();
+    const m = await nc.request(subject, sc.encode(JSON.stringify({ ...payload, plane: PLANE })), { timeout: 2000 });
+    const out = JSON.parse(sc.decode(m.data) || '{}');
+    await nc.close();
+    return out;
+  } catch (err) {
+    if (err.status === 403) throw err;
+    return null;
+  }
+}