Distructuring cheatsheet

Since I keep find myself forgot the ES6 destructuring syntax again and again I decided to publish this cheatsheet:

If you want to print one property of object:

const object = {name:'vasia'};
const {name} = object; 
console.log(`${name}`); // vasia 

If you want to this property to be named differently (bio)

const object = {name:'vasia'};
const {name: bio} = object; 

console.log(`${bio}`); // vasia 

If this property is inside other property (person)

const object ={person: {name:'vasia'}};
const {person:{name}} = object;

console.log(`${name}`); // vasia 

Hope this post will make me remember...

Kubernetes - Old replica sets remains after deployment

In this post i will write about annoying Kubernetes problem I managed to solve (at least I think it solved)
after long struggle.

So, here is the problem:

After running update-deployment-image command:

kubectl set image deployment/my-app my-app=gcr.io/my-cloud/my-app:new-image-tag 

The kubernetes showed that although the new image successfully updated, the old replicaset still remains:

Old replicates are all with 0 pods, but not removed.

Solution

The solution I found is to change the "selector" node in deployment configuration -
From:

  selector:
    matchLabels:
      app: my-app
      version: $SHORT_SHA

To

  selector:
    matchLabels:
      app: my-app

(Remove the "version" label)
And to add revisionHistoryLimit entry

spec:
  replicas: 2
  revisionHistoryLimit: 0
  selector:
    matchLabels:
      app: my-app

Make travis to push tags

What is travis you already know from the previous post. But what the kubernetes is?
According to the docs: "Kubernetes is a portable, extensible open-source platform for managing containerized workloads and services, that facilitates both declarative configuration and automation. It has a large, rapidly growing ecosystem. Kubernetes services, support, and tools are widely available"
Get the long things shorter: kubernetes is the way to upload applications to google cloud, and also it can do lots of other things.

My Goal

So, my goal was: to get things published to cloud after all the testing stuff was done. (or after the travis finished)
Google cloud builder - another google cloud tool can be activated in response to push to some branch or in response to publishing some tag

In other words - my goal is to make travis to push tag after successful testing of every commit.

After Success Hook

Fortunately I found that travis has a after_success hook which I can utilise for my scenario:

language: node_js
node_js:
  - "9"
sudo: required
branches:
  except:
    - /^v.*\_.*/ 
dist: trusty
addons:
  chrome: stable
cache:
  directories:
  - $HOME/.npm
env:
  matrix:
    - MONGODB=3.6.6
before_install:
  - export GITHUBKEY=put-here-your-github-auth-token-key
install:
  ...
  ...
script:
  # run build script specified in package.json
  - npm run tslint
  - npm run test
  - npm run build
after_success:
  # CREATE GIT TAG
  - bash ./scripts/push_tag.sh

And here is the bash script code:

#!/bin/sh
git config --global user.email "koko@moko.com"
git config --global user.name "koko"
# Version key/value should be on his own line
PACKAGE_VERSION=$(cat package.json \
  | grep version \
  | head -1 \
  | awk -F: '{ print $2 }' \
  | sed 's/[",]//g' \
  | tr -d '[[:space:]]')

# should start cloud build only on prod test dev branches 
if [[ "${TRAVIS_BRANCH}" = prod || "${TRAVIS_BRANCH}" = test || "${TRAVIS_BRANCH}" = dev ]]; then
    export GIT_TAG="v${PACKAGE_VERSION}_${TRAVIS_BUILD_NUMBER}"
    echo "tag is ${GIT_TAG}"
    git tag $GIT_TAG -a -m "Generated tag from TravisCI build $TRAVIS_BUILD_NUMBER [ci skip]" $TRAVIS_BRANCH
    git push --tags https://$GITHUBKEY@github.com/oyrname/yourrepo
fi

Notice, that travis will react to the tag pushed by himself unless except entry configured properly:

branches:
  except:
    - /^v.*\_.*/