Configure nginx-ingress to forward bytes to underlying HTTP service, as they arrive

Question

I'm building an API than enable users to stream (push) large content through HTTP and I would like to be able to process the request from a nodejs express server while the client is still pushing .

client.js

const request = require('request');
someReadableStream.pipe(request({
    method: "POST",
    uri: `${process.env.SERVER_URL || "https://streaming.service.com/"}/`,
    headers: {
      'Authorization': `Bearer ${API_TOKEN}`,
    },
}));

server.js

const express = require('express');
const app = express();
app.post('/', function rootPostHandler(req, res) {
  console.log('request received');
  const tickInterval = setInterval(() => console.log('tick'), 1000);
  req.on('data', (chunk) => console.log('data received'));
  req.on('end', () => {
    console.log('request end received');
    clearInterval(tickInterval);
    res.end('done')
  });
});

app.listen(process.env.PORT);

Everything works as expected on my development server: server receives data and can start processing it while client is still pushing (see per-second tick s in output below).

dev server output:

request received
data received
data received
data received
tick
data received
data received
data received
tick
data received
data received
data received
tick
data received
data received
request end received

Now, when we deploy the same server code to our kubernetes cluster, initial experiments suggest that Nginx Ingress (or some other K8s component) wait the request to be completed before sending it to the underlying HTTP service (no tick in output below).

server pod logs

request received
data received
data received
data received
data received
data received
data received
data received
data received
data received
data received
data received
request end received

kubernetes config

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress
  labels:
    tier: ingress
  annotations:
    kubernetes.io/ingress.class: "nginx"
    cert-manager.io/cluster-issuer: "issuer"
    nginx.ingress.kubernetes.io/proxy-body-size: 30720m
    nginx.ingress.kubernetes.io/proxy-connect-timeout: "180"
    nginx.ingress.kubernetes.io/proxy-read-timeout: "180"
    nginx.ingress.kubernetes.io/proxy-send-timeout: "180"
    nginx.ingress.kubernetes.io/enable-cors: "true"
    nginx.ingress.kubernetes.io/cors-allow-origin: "*"
    nginx.ingress.kubernetes.io/configuration-snippet: |
      proxy_pass_request_headers      on;
spec:
  ingressClassName: nginx
  tls:
    - hosts:
        - streaming.service.com
      secretName: streaming-tls
  rules:
    - host: streaming.service.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: streaming
                port:
                  number: 80
---
apiVersion: v1
kind: Service
metadata:
  name: streaming
  labels:
    app: streaming
spec:
  type: ClusterIP
  clusterIP: None
  sessionAffinity: ClientIP
  ports:
    - port: 80
  selector:
    app: streaming

Question: Is here a way to tell nginx-ingress to forward bytes to underlying HTTP service as they arrive, through annotations or snippets for example?

Answer 1

Answering to my own question since it may help others

All you have to do is to add nginx.ingress.kubernetes.io/proxy-request-buffering: "off" annotation

New Ingress configuration

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-stream
  labels:
    name: ingress-stream
    tier: ingress
  annotations:
    nginx.ingress.kubernetes.io/proxy-request-buffering: "off"  # here
spec:
  ingressClassName: nginx
  rules:
    - host: streaming.service.com
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: streaming
                port:
                  number: 80