arun-gupta

# Docker Machine for Consul
docker-machine \
   create \
   -d virtualbox \
   consul-machine

# Start Consul
docker $(docker-machine config consul-machine) run -d --restart=always \
         -p "8500:8500" \
         -h "consul" \

vasanthk

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

1. Clarify and agree on the scope of the system

• User cases (description of sequences of events that, taken together, lead to a system doing something useful)
  • Who is going to use it?
  • How are they going to use it?

watson

[
  "😁",
  "😂",
  "😃",
  "😄",
  "😅",
  "😆",
  "😉",
  "😊",
  "😋",

xkr47

# input: fullchain.pem and privkey.pem as generated by the "letsencrypt-auto" script when run with
# the "auth" aka "certonly" subcommand

# convert certificate chain + private key to the PKCS#12 file format
openssl pkcs12 -export -out keystore.pkcs12 -in fullchain.pem -inkey privkey.pem

# convert PKCS#12 file into Java keystore format
keytool -importkeystore -srckeystore keystore.pkcs12 -srcstoretype PKCS12 -destkeystore keystore.jks

# don't need the PKCS#12 file anymore

mfuerstenau

  ZigZag-Encoding
  ---------------
  
  Maps negative values to positive values while going back and
  forth (0 = 0, -1 = 1, 1 = 2, -2 = 3, 2 = 4, -3 = 5, 3 = 6 ...)

  (i >> bitlength-1) ^ (i << 1)

  with "i" being the number to be encoded, "^" being
  XOR-operation and ">>" would be arithemtic shifting-operation

ndolgov

import org.apache.spark.sql.SparkSession;

public class SparkDriver {
    public static void main(String[] args) {
        final SparkSession session = SparkSession.builder().
            appName("MySparkApp" + System.currentTimeMillis()).
            master(SparkEnvCfg.sparkMasterUrl()).
            config(SparkEnvCfg.SPARK_EXECUTOR_MEMORY, "1g").
            config(SparkEnvCfg.SPARK_SERIALIZER, SparkEnvCfg.KRYO).
            config(SparkEnvCfg.SPARK_SQL_SHUFFLE_PARTITIONS, "2").

miguno

#!/usr/bin/env bash
#
# File:      kafka-move-leadership.sh
#
# Description
# ===========
#
# Generates a Kafka partition reassignment JSON snippet to STDOUT to move the leadership
# of any replicas away from the provided "source" broker to different, randomly selected
# "target" brokers.  Run this script with `-h` to show detailed usage instructions.

lavalamp

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) }

sadikovi

package mobilepackage

import io.gatling.core.Predef._
import io.gatling.core.session._
import io.gatling.http.Predef._
import scala.concurrent.duration._
import scala.util.parsing.json._
import general._

class LoginSimulation extends Simulation {

ivanursul

package org.lnu.is.integration.access

import io.gatling.core.Predef.checkBuilder2Check
import io.gatling.core.Predef.doIf
import io.gatling.core.Predef.exec
import io.gatling.core.Predef.findCheckBuilder2ValidatorCheckBuilder
import io.gatling.core.Predef.foreach
import io.gatling.core.Predef.feed
import io.gatling.core.Predef.stringToExpression
import io.gatling.core.Predef.validatorCheckBuilder2CheckBuilder