Alexander Hutorezki olekhy

Source(read) 概述

Sink 对 Source 有两种请求:

read: 向 Source 请求数据，通过 read(null, currCb) 来请求。
abort: 通知 Source 终止当前的 stream，通过 read(endOrError, currCb) 来请求。endOrError 的类型是 true | Error，表示是一次正常的终止还是异常的终止。

对于 read 请求，Sink 应该基于上一次的 read 请求回调了，再发起新的 read 请求这样的规则。对于 abort 请求，由于有时 Source 也不知道何时需要 abort(出现了异常或者外部其他条件触发的)，因此可能在上一次 read 没有回调就发生。

对于 Sink 的 read 请求，如果”重入“(上一次 read 没有结束，新的 read 来了)，Source 完成实际资源的读取后，仅仅调用最后一个传入的 currCb 来传递数据。

Getting GCP access token from a service account key

Use your service account's key JSON file to get an access token to call Google APIs.

Good for seeing how things work, including the creation of JWT token.

To create a JWT token, you can replace create-jwt-token.sh script with tools like step.

If you just want to get an access token for a service account,

DDD, CQRS and Event Sourcing in PHP

Broadway - Infrastructure and testing helpers for creating CQRS and event sourced applications
EventCentric.Core - Event Sourcing and CQRS in PHP
LiteCQRS - Small convention based CQRS library for PHP
predaddy - Common DDD classes including an annotation driven message bus and tools for CQRS and Event Sourcing
ProophEventSourcing - Provides basic functionality for event-sourced aggregates
ProophEventStore - PHP 5.4+ EventStore Implementation
ProophServiceBus - PHP Enterprise Service Bus Implementation supporting CQRS and DDD

Installing Docker CE on Ubuntu 17.10 Artful Aardvark

As of 20/10/2017, a release file for Ubuntu 17.10 Artful Aardvark is not available on Download Docker.

sudo apt-get update
sudo apt-get install apt-transport-https ca-certificates curl software-properties-common
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo apt-key fingerprint 0EBFCD88

Sed Cheat Sheet

Sed command line options

sed [options] sed-command [input-file]

Option	Description	Example

Here's how to test whether a parameter is unset, or empty ("Null") or set with a value:

+--------------------+----------------------+-----------------+-----------------+
|                    |       parameter      |     parameter   |    parameter    |
|                    |   Set and Not Null   |   Set But Null  |      Unset      |
+--------------------+----------------------+-----------------+-----------------+
| ${parameter:-word} | substitute parameter | substitute word | substitute word |
| ${parameter-word}  | substitute parameter | substitute null | substitute word |
| ${parameter:=word} | substitute parameter | assign word     | assign word     |
| ${parameter=word}  | substitute parameter | substitute null | assign word     |

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

	import UUID

	from sqlalchemy.dialects.mysql import BINARY
	from sqlalchemy.types import TypeDecorator


	class BinaryUUID(TypeDecorator):
	'''Optimize UUID keys. Store as 16 bit binary, retrieve as uuid.
	inspired by:
	http://mysqlserverteam.com/storing-uuid-values-in-mysql-tables/

	https://trac.ffmpeg.org/wiki/Capture/Desktop

	ffmpeg -framerate 25 -video_size 1024x768 -f x11grab -i :0.0+100,200 -f alsa -ac 2 -i pulse -vcodec libx264 -crf 0 -preset ultrafast -acodec pcm_s16le output.mkv


	losless

	ffmpeg -video_size 1920x1080 -framerate 30 -f x11grab -i :0.0 -c:v libx264 -qp 0 -preset ultrafast capture.mkv

	<IfModule mod_rewrite.c>
	<IfModule mod_negotiation.c>
	Options -MultiViews
	</IfModule>

	RewriteEngine On

	# Force HTTPS - Proto needed for AWS ELB
	RewriteCond %{HTTP:X-Forwarded-Proto} !https
	RewriteCond %{HTTP_USER_AGENT} !^ELB-HealthChecker