huangwenwei.com wenweih

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Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.

Prerequisites

Sending emails with ActionMailer and Sidekiq

Send email asynchroniously using Sidekiq.

ActionMailer

Create your mailer us usual:

注意：本文内容适用于 Tmux 2.3 及以上的版本，但是绝大部分的特性低版本也都适用，鼠标支持、VI 模式、插件管理在低版本可能会与本文不兼容。

Tmux 快捷键 & 速查表 & 简明教程

启动新会话：

tmux [new -s 会话名 -n 窗口名]

恢复会话：

Common Options

-#, --progress-bar Make curl display a simple progress bar instead of the more informational standard meter.

-b, --cookie <name=data> Supply cookie with request. If no =, then specifies the cookie file to use (see -c).

-c, --cookie-jar <file name> File to save response cookies to.

Optimizing postgresql table for more than 100K inserts per second

Create UNLOGGED table. This reduces the amount of data written to persistent storage by up to 2x.
Set WITH (autovacuum_enabled=false) on the table. This saves CPU time and IO bandwidth on useless vacuuming of the table (since we never DELETE or UPDATE the table).
Insert rows with COPY FROM STDIN. This is the fastest possible approach to insert rows into table.
Minimize the number of indexes in the table, since they slow down inserts. Usually an index on time timestamp with time zone is enough.
Add synchronous_commit = off to postgresql.conf.
Use table inheritance for fast removal of old data:

# referecing: # https://www.digitalocean.com/community/tutorials/how-to-install-apache-kafka-on-ubuntu-14-04 # https://chongyaorobin.wordpress.com/2015/07/08/step-by-step-of-install-apache-kafka-on-ubuntu-standalone-mode/

Add 'kafka' user:

$ sudo useradd kafka -m

Install Java:

	package main

	import (
	"bytes"
	"encoding/hex"
	"encoding/json"
	"io/ioutil"
	"log"
	"net/http"

	class MyJob < ActiveJob::Base
	queue_as :urgent

	rescue_from(NoResultsError) do
	retry_job wait: 5.minutes, queue: :default
	end

	def perform(*args)
	MyService.call(*args)
	end

	# run in sudo
	# Before installing, make sure you have installed all the needed packages
	sudo apt-get install libtool pkg-config build-essential autoconf automake
	sudo apt-get install libzmq-dev

	# Install libsodium
	git clone git://github.com/jedisct1/libsodium.git
	cd libsodium
	./autogen.sh
	./configure && make check

	/*
	* Genarate rsa keys.
	*/

	package main

	import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"