hello-1984-CSDN博客

原创 Decorator in Python

A decorator is a callable that takes another function as argument (the decorated function).The decorator may perform some processing with the decorated function, and returns it or replaces it with an...

2019-07-08 23:33:24 178

原创 Flask 源码阅读笔记

A web site using Flask FrameworkFlask for service logicGunicorn hosts the flask appFinally nginx esponsible for：buffer slow clients on the Internetload balance for many gunicorn processesWAF ...

2019-07-07 21:19:50 186

原创 ansible-role 加速mysql的安装过程

ansilbe 的原理图如下：我们安装mysql的一种方式是，适用mysql.com提供的二进制包。整个过程可以分为：下载包在目标机器解压包，安装db Server 初始化db 启动db Server 修改root密码使用ansible role来组织tasks和vars在ansible role里，变量的优先级从高到低顺序如下：vars in command ...

2019-07-03 09:20:15 271

原创 nginx 之一

nginx 相对于apache httpd，最突出的不同之处：nginx除了代理http流量之外，还可以代理四层流量 nginx在http模块上的分阶段处理，将nginx进化了一个强大的可编程平台...

2019-06-30 22:19:48 76

原创逾百台规模服务器管理心得

最近的项目涉及了将近百台服务器，但是维护下来，并不十分繁琐。服务器规模简介（加入了混淆变量，与真实情况不符）如下：IDC in Beijing: 20phy machinesIDC in HongKong: 30 phy machinesIDC in Guangzhou: 10 phy machinesECS in VPC(beijing/guangzhou/shenzhen)...

2019-06-27 10:53:26 459

原创 rethink of tcp

TCP状态迁跃如下：主动关闭一方会进入time_wati，与应用是客户端服务端无关被动关闭一方会进入close_wait，与应用是客户端服务端无关listening socket会维护两个队列：incomplete connection queue => max(64, net.ipv4.tcp_max_syn_backlog) when syncoo...

2019-06-25 22:28:41 90

原创 ssh 端口转发

ssh 端口转发可以理解，ssh 作为一种数据通道而存在。所谓的端口转发，就存在一个直接业务。ssh 在建立ssh 会话时启动额外的端口来完成端口转发，分为local forwardssh -L [<localhost>]:<port>:<remote>:<port> remote hostssh 在ssh客户端建立port，...

2019-06-25 21:46:54 87

原创 virtualbox 网络模型

virtualboxNATvirtualbox 为每个vm虚拟了一个router，vm挂在router下，vm之间不互联，virtualbox 透明的转发流量vm到外部，外部通过端口转发（宿主机会启动一个端口listen，vm相当于在一个reverse proxy后面）到vm。NAT networkvirtualbox 虚拟了若干router，vm可以选择挂在同一个router下进...

2019-06-22 22:11:49 193

greenplum product document

Pivotal Greenplum Database Documentation everything about greenplum

2018-02-03

Semantics of Asynchronous JavaScript

The Node.js runtime has become a major platform for de- velopers building cloud, mobile, or IoT applications using JavaScript. Since the JavaScript language is single threaded, Node.js programs must make use of asynchronous callbacks and event loops managed by the runtime to ensure appli- cations remain responsive. While conceptually simple, this programming model contains numerous subtleties and be- haviors that are de ned implicitly by the current Node.js implementation. This paper presents the rst comprehensive formalization of the Node.js asynchronous execution model and de nes a high-level notion of async-contexts to formalize fundamental relationships between asynchronous events in an application. These formalizations provide a foundation for the construction of static or dynamic program analysis tools, support the exploration of alternative Node.js event loop implementations, and provide a high-level conceptual framework for reasoning about relationships between the execution of asynchronous callbacks in a Node.js application.

2018-01-31

EAP-SIM-AKA-PEAP认证

wlan EAP认证网络认证信令流程 SIM无感知认证

2015-09-07

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