yanmhlv

import "sync"

type Cond struct {
	lock    sync.RWMutex
	changed chan struct{}
}

func (c *Cond) Listen() <-chan struct{} {
	c.lock.RLock()
	defer c.lock.RUnlock()

yanmhlv

package main

import (
	"bytes"
	"errors"
	"html/template"
	"net/http"
	"path/filepath"
)

yanmhlv

package main

import (
	"database/sql/driver"
	"encoding/json"

	"github.com/jinzhu/gorm"
	_ "github.com/lib/pq"
)

yanmhlv

package cond

type Cond struct {
	lock    sync.RWMutex
	changed chan struct{}
}

func newCond() *Cond {
	return &Cond{changed: make(chan struct{})}
}

yanmhlv

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?

yanmhlv

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
)

func handleResponse[T any](resp *http.Response, err error, t *T) error {
	if err != nil {

yanmhlv

CREATE USER admin; -- create user with name 'admin'
ALTER USER admin WITH PASSWORD 'hello123'; -- set password

GRANT SELECT ON users TO admin; -- give 'select' access on 'users' table to 'admin' user
REVOKE SELECT ON users FROM admin; -- revoke access on 'users' table from 'admin' user

GRANT SELECT ON ALL TABLES IN SCHEMA public TO admin; -- give access to all tables in public schema to 'admin' user
REVOKE ALL ON ALL TABLES IN SCHEMA public FROM admin; -- revoke access on all tables from 'admin' user

DROP USER admin;

yanmhlv

package main

import (
	"bytes"
	"io/ioutil"

	"github.com/labstack/echo"
	"github.com/labstack/echo/engine/standard"
	mw "github.com/labstack/echo/middleware"
)

yanmhlv

#Newbie programmer
def factorial(x):
    if x == 0:
        return 1
    else:
        return x * factorial(x - 1)
print factorial(6)


#First year programmer, studied Pascal

yanmhlv

=Algorithms 
  + Дискретная математика для программистов         Г. Хаггард 
  + Concrete Mathematics: A Foundation for Computer Science  Ronald L. Graham 
  + Алгоритмы. Построение и анализ   Томас Кормен 
  + Искусство программирования. Том 1. Основные алгоритмы   Дональд Кнут

  + The Algorithm Design Manual Steven S Skiena 
  + Introduction to Distributed Algorithms Gerard Tel 
  + Clever Algorithms: Nature-Inspired Programming Recipes Jason Brownlee