Test dropped requests during a rolling kubernetes deployment.

client.js

const fetch = require('node-fetch');

const aggregation = [];

function getTextFromFetchError(error) {
  let message = '';
  switch (error.message) {
    case 'Only HTTP(S) protocols are supported':
      message = 'Did you forget the scheme (http:// or https://) in the cli argument?';
      break;
    default:
      message = error.message;
      break;
  }
  return message;
}

async function makeRequest() {
  const time = Date.now();
  try {
    const response = await fetch(process.argv[2]);
    const text = await response.text()
    aggregation.push({ time: Date.now(), text, status: await response.status});
    console.log(`${text} ${response.status} ${Date.now() - time}ms`);
  } catch(e) {
    const text = getTextFromFetchError(e);
    aggregation.push({ time: Date.now(), text, status: await -1 });
    console.log(`Errored connection after ${Date.now() - time}ms - ${text}`);
  }
}

function printSummary() {
  const summary = aggregation.reduce((memo, current) => {
    if (memo.responses[current.text] === undefined) {
      memo.responses[current.text] = 0;
    } else {
      memo.responses[current.text]++;
    }
    if (memo.statusCodes[current.status] === undefined) {
      memo.statusCodes[current.status] = 0;
    } else {
      memo.statusCodes[current.status]++;
    }
    return memo;
  }, {responses: {}, statusCodes: {}});
  console.log(summary);
}

function signalHandler(interval) {
  console.log('Signal received');
  clearInterval(interval);
}

async function main() {
  const interval = setInterval(makeRequest, 500);
  const handler = signalHandler.bind(null, interval); 
  process.on('SIGINT', handler);
  process.on('SIGHUP', handler);
  process.on('SIGTERM', handler);
  process.on('exit', printSummary);
}

try {
  main();
} catch (e) {
  console.log(e);
}

Dockerfile

FROM node:alpine
WORKDIR /app
COPY server.js .
CMD node /app/server.js

patch.sh

CURRENT="$(kubectl --context=minikube get deployment -o json hello-world | jq -r '.spec.template.spec.containers[0].env[0].value')"
if [ "${CURRENT}" = "Response A" ]; then
  MESSAGE="Response B"
else
  MESSAGE="Response A"
fi
##kubectl --containers=minikube patch deployment hello-world --context=$ENV --patch "{\"spec\": {\"template\": {\"spec\":  {\"containers\": [{\"name\": \"${SERVICE}\",\"env\": [ {\"NAME\": \"${MESSAGE}\"}]}]}}}}"
kubectl --context=minikube patch deployment hello-world --type='json' -p="[{\"op\": \"replace\", \"path\": \"/spec/template/spec/containers/0/env/0/value\", \"value\": \"${MESSAGE}\"}]"

server.js

const http = require('http');

const server = http.createServer((req, res) => {
  console.log('Request received');
  if (process.env.SIMULATE_CONNECTION_FAIULRE) {
    res.socket.destroy();
    console.log('Killing the connection');
    return;
  } else {
    setTimeout(() => {
      const message = `Response sent by ${process.env.NAME ? process.env.NAME : 'Node service' } ${process.env.HOSTNAME || '' }`;
      console.log(message);
      res.end(message);
    }, process.env.TIMEOUT || 10000);
  }
});


function signalHandler() {
  console.log('Signal received, shutting down.');
  server.close()
}
if (process.env.HANDLE_SIGNALS) {
  console.log('Properly handling signals');
  process.on('SIGINT', signalHandler);
  process.on('SIGHUP', signalHandler);
  process.on('SIGTERM', signalHandler);
} else {
  console.log('Not handling signals!');
}

server.listen(process.env.PORT || 3333, () => {console.log('now listening')});

test.yaml

kind: Service
apiVersion: v1
metadata:
  name: hello-world
spec:
  selector:
    app: hello-world
  type: NodePort
  ports:
    - protocol: TCP
      port: 3333
      targetPort: 3333
      nodePort: 32222
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-world
  labels:
    app: hello-world
spec:
  replicas: 2
  selector:
    matchLabels:
      app: hello-world
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
    type: RollingUpdate
  template:
    metadata:
      labels:
        app: hello-world
    spec:
      containers:
        - name: hello-world
          image: hello-world:hostname
          env:
            - name: NAME
              value: "Response A"
            - name: TIMEOUT
              value: "15000"
            - name: HANDLE_SIGNALS
              value: "1"
          ports:
            - containerPort: 3333
      terminationGracePeriodSeconds: 16

yarn.lock

# THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
# yarn lockfile v1


bluebird@^3.5.0:
  version "3.5.4"
  resolved "https://registry.yarnpkg.com/bluebird/-/bluebird-3.5.4.tgz#d6cc661595de30d5b3af5fcedd3c0b3ef6ec5714"
  integrity sha512-FG+nFEZChJrbQ9tIccIfZJBz3J7mLrAhxakAbnrJWn8d7aKOC+LWifa0G+p4ZqKp4y13T7juYvdhq9NzKdsrjw==

lodash@^4.17.11:
  version "4.17.11"
  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.11.tgz#b39ea6229ef607ecd89e2c8df12536891cac9b8d"
  integrity sha512-cQKh8igo5QUhZ7lg38DYWAxMvjSAKG0A8wGSVimP07SIUEK2UO+arSRKbRZWtelMtN5V0Hkwh5ryOto/SshYIg==

node-fetch@^2.3.0:
  version "2.3.0"
  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.3.0.tgz#1a1d940bbfb916a1d3e0219f037e89e71f8c5fa5"
  integrity sha512-MOd8pV3fxENbryESLgVIeaGKrdl+uaYhCSSVkjeOb/31/njTpcis5aWfdqgNlHIrKOLRbMnfPINPOML2CIFeXA==

psl@^1.1.28:
  version "1.1.31"
  resolved "https://registry.yarnpkg.com/psl/-/psl-1.1.31.tgz#e9aa86d0101b5b105cbe93ac6b784cd547276184"
  integrity sha512-/6pt4+C+T+wZUieKR620OpzN/LlnNKuWjy1iFLQ/UG35JqHlR/89MP1d96dUfkf6Dne3TuLQzOYEYshJ+Hx8mw==

punycode@^2.1.1:
  version "2.1.1"
  resolved "https://registry.yarnpkg.com/punycode/-/punycode-2.1.1.tgz#b58b010ac40c22c5657616c8d2c2c02c7bf479ec"
  integrity sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A==

request-promise-core@1.1.2:
  version "1.1.2"
  resolved "https://registry.yarnpkg.com/request-promise-core/-/request-promise-core-1.1.2.tgz#339f6aababcafdb31c799ff158700336301d3346"
  integrity sha512-UHYyq1MO8GsefGEt7EprS8UrXsm1TxEvFUX1IMTuSLU2Rh7fTIdFtl8xD7JiEYiWU2dl+NYAjCTksTehQUxPag==
  dependencies:
    lodash "^4.17.11"

request-promise@^4.2.4:
  version "4.2.4"
  resolved "https://registry.yarnpkg.com/request-promise/-/request-promise-4.2.4.tgz#1c5ed0d71441e38ad58c7ce4ea4ea5b06d54b310"
  integrity sha512-8wgMrvE546PzbR5WbYxUQogUnUDfM0S7QIFZMID+J73vdFARkFy+HElj4T+MWYhpXwlLp0EQ8Zoj8xUA0he4Vg==
  dependencies:
    bluebird "^3.5.0"
    request-promise-core "1.1.2"
    stealthy-require "^1.1.1"
    tough-cookie "^2.3.3"

stealthy-require@^1.1.1:
  version "1.1.1"
  resolved "https://registry.yarnpkg.com/stealthy-require/-/stealthy-require-1.1.1.tgz#35b09875b4ff49f26a777e509b3090a3226bf24b"
  integrity sha1-NbCYdbT/SfJqd35QmzCQoyJr8ks=

tough-cookie@^2.3.3:
  version "2.5.0"
  resolved "https://registry.yarnpkg.com/tough-cookie/-/tough-cookie-2.5.0.tgz#cd9fb2a0aa1d5a12b473bd9fb96fa3dcff65ade2"
  integrity sha512-nlLsUzgm1kfLXSXfRZMc1KLAugd4hqJHDTvc2hDIwS3mZAfMEuMbc03SujMF+GEcpaX/qboeycw6iO8JwVv2+g==
  dependencies:
    psl "^1.1.28"
    punycode "^2.1.1"