Cuneytt

Kubectl output options

Let's look at some basic kubectl output options.

Our intention is to list nodes (with their AWS InstanceId) and Pods (sorted by node).

We can start with:

kubectl get no

Cuneytt

There are three easy to make mistakes in go. I present them here in the way they are often found in the wild, not in the way that is easiest to understand.

All three of these mistakes have been made in Kubernetes code, getting past code review at least once each that I know of.

1. Loop variables are scoped outside the loop.

What do these lines do? Make predictions and then scroll down.

func print(pi *int) { fmt.Println(*pi) }

Cuneytt

before_script:
  - export GOPATH=$(pwd)

stages:
  - build
  - test
  - deploy

validate-schema:
  image: truongsinh/pg-client:9.4

Cuneytt

# Join multiple lines without new line
value: >
        part 1
        part 2
        
# Join with newline
value2: |
        line 1
        line 2

Cuneytt

/*
********************************************************************************
Golang - Asterisk and Ampersand Cheatsheet
********************************************************************************

Also available at: https://play.golang.org/p/lNpnS9j1ma

Allowed:
--------
p := Person{"Steve", 28} 	stores the value

Cuneytt

#!/bin/bash
# Inspired by http://dl.getipaddr.net/ and http://curl.haxx.se/mail/archive-2014-10/0006.html
file=path/to/file
bucket=your-bucket
contentType="application/octet-stream"
dateValue=`date -R`
resource="/${bucket}/${file}"
s3Key=`curl -s http://169.254.169.254/latest/meta-data/iam/security-credentials/ec2-app-role | grep 'AccessKeyId' | sed 's/.* "\([^"]*\).*/\1/'`
s3Secret=`curl -s http://169.254.169.254/latest/meta-data/iam/security-credentials/ec2-app-role | grep 'SecretAccessKey' | sed 's/.* "\([^"]*\).*/\1/'`
token=`curl -s http://169.254.169.254/latest/meta-data/iam/security-credentials/ec2-app-role | grep 'Token' | sed 's/.* "\([^"]*\).*/\1/'`

Cuneytt

Build docker image

$ cd /path/to/Dockerfile
$ sudo docker build .

View running processes

Cuneytt

# For example here I create thumbnails of images in the current directory, inserting a "_tn" string into the input filename, to create the appropraite output image filename.

  convert *.jpg  -thumbnail 120x90 -set filename:fname '%t_tn'
          +adjoin '%[filename:fname].gif'

Because of this the "-set" option can actually define ANY setting with ANY value.
 convert rose: -set filename:my_area '%wx%h' 'rose-%[filename:my_area].png'

To get the exact original filename of the image use '%d/%f' or '%d/%t.%e'.