boseabhishek

package main

import (
	"fmt"
	"os"
	"os/exec"
)

func main() {
	if len(os.Args) == 1 {

boseabhishek

// usage:
// go run waitfor.go <num>
// where, num can be 1 or 2 or 3 or 4.

package main

import (
	"context"
	"encoding/json"
	"fmt"

boseabhishek

panic signals "the programmer has made a fundamental mistake and execution cannot continue safely", whereas os.Exit signals "the programmer has decided that the process should terminate here" — different meanings. Also, important difference in behavior: panic will unwind the callstack, which means it will call any pending defer statements; os.Exit will just do a hard kill, so it won't.

boseabhishek

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?

boseabhishek

Notes

PEM vs Base64? Why both?

PEM - Format type Base64 - content of the file encoding type

PEM (originally “Privacy Enhanced Mail”) is the most common format for X.509 certificates, CSRs, and cryptographic keys(public/private keys).

A PEM file is a text file containing one or more items in Base64 ASCII encoding, each with plain-text headers and footers (e.g. -----BEGIN CERTIFICATE----- and -----END CERTIFICATE-----).

boseabhishek

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

# add bazel `golang` rules

http_archive(
    name = "io_bazel_rules_go",
    sha256 = "a8d6b1b354d371a646d2f7927319974e0f9e52f73a2452d2b3877118169eb6bb",
    urls = [
        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.23.3/rules_go-v0.23.3.tar.gz",
        "https://github.com/bazelbuild/rules_go/releases/download/v0.23.3/rules_go-v0.23.3.tar.gz",

boseabhishek

Elasticsearch

Definition

From official website, Elasticsearch is a distributed, RESTful search and analytics engine capable of addressing a growing number of use cases. As the heart of the Elastic Stack, it centrally stores your data for lightning fast search, fine‑tuned relevancy, and powerful analytics that scale with ease.

Concept

Data in Elasticsearch is organized into indices. Each index is made up of one or more shards. Each shard is an instance of a Lucene index, which you can think of as a self-contained search engine that indexes and handles queries for a subset of the data in an Elasticsearch cluster. For details on shards and indices, see here

boseabhishek

# REDIS cheatsheet

### delete

1. delete all keys in ALL dbs

FLUSHALL

2. delete all keys in a specific DB

boseabhishek

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"time"

boseabhishek

package sample.akka.testkit

import akka.actor.ActorSystem
import akka.actor.Actor
import akka.testkit.{TestKit, TestActorRef}
import org.scalatest.matchers.MustMatchers
import org.scalatest.WordSpec

class ImplicitSenderTest extends TestKit(ActorSystem("testSystem"))
  // Using the ImplicitSender trait will automatically set `testActor` as the sender