3 unstable releases
0.2.1 | Feb 27, 2022 |
---|---|
0.1.1 | Jan 30, 2022 |
0.1.0 | Jan 26, 2022 |
#27 in #nats
39KB
666 lines
NATS proxy service
Simple tool to forward specific topics from one nats.io cluster to the same server or another. Provides support to process messages with deno Javascript or TypeScript code.
Example
Imagine that we use nats.io to relay events for every confirmed or canceled order in our shopping platform:
./naps --source nats://aws:4222 --destination nats://aks:4222 --topics "orders.>"
If the --script
flag is present, naps
will spawn a Deno
runtime with all v8
capabilities plus promises and all event loop goodies, allowing you to, for example, only
keep the confirmed ones and relay them to the myapp.orders.confirmed
. You only have to code a recv
function
with the following signature:
interface RecvResult {
topic: string,
msg: string
};
function recv(topic: string, data: Uint8Array): boolean | RecvResult {
//... your code here...
}
- If the function returns
true
, the message will be simply forwarded to the same topic. Do note that the message will end up twice in the topic - If the function returns
false
, this message will be discarded - Finally, when
RecvResult
is returned, that data will be sent over the nats wire.
Processing Example
./naps --source nats://aws:4222 --destination nats://aks:4222 --topics "myapp.v1.orders" --script "
import { Buffer } from 'http://deno.land/x/node_buffer/index.ts';
interface Order {
status: 'confirmed' | 'canceled',
user: string,
amount: number,
item: any
};
function processOrder(data: Buffer): RecvResult {
const orderRaw = data.toString();
const order = JSON.parse(orderRaw) as Order;
// Skip orders that are not confirmed
if (order.status !== 'confirmed') {
return false;
}
return {
topic: 'myapp.v1.orders.confirmed',
msg: orderRaw
};
}
function recv(topic, uint8array) {
switch (topic) {
case "myapp.v1.orders":
return processOrder(Buffer.from(uint8array))
default:
// nothing to do...
}
}
"
Thanks
- Thanks to the rust community for such a good documentation and wide range of libraries which have made this journey far easier.
- Thanks to the denoland community for pointing me into the right direction. Specially Andreu Botella, denoland contributor who patiently answered all my questions and guided me to a decent solution. Many thanks, man!
TODOs
- Support for NATS TLS connections
- JetStream
- Feature Sagas by allowing to return multiple
RecvResult
when employing deno runtime
Dependencies
~216MB
~4.5M SLoC