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SEARCH KEYWORD -- MICRO SERVICE

  How to do pprof for gRPC service

gRPC is a RPC framework based on HTTP and is frequently used for communications among micro service inside the same organization network. However,  the service functions cannot be accessed via normal HTTP URL as it's not a WEB framework. In this case, how to do pprof on a gRPC service? The trick is starting a HTTP server asynchronously while starting the gRPC service. This HTTP server can be accessed to run prrof debug. go func(){ http.ListenAndServe(":10001", nil) }() Since it uses the de...

   GOLANG,PPROF,GRPC     2021-01-29 23:11:33

  What is Hystrix and How does Hystrix work

Background In distributed systems, there is one effect where the unavailability of one service or some services will lead to the service unavailability of the whole system, this is called service avalanche effect. A common way to prevent service avalanche is do manual service fallback, in fact Hystrix also provides another option beside this. Definition of Service Avalanche Effect Service avalanche effect is a kind of effect where the service provider fails to provide service which causes t...

   AVALANCHE EFFECT,HYSTRIX,DISTRIBUTED SYSTEM     2019-02-04 06:00:38

  Some thoughts about microservice adoption

Nowadays microservice is very popular among companies with the increasing complexity of systems. The goal is to make each microservice to handle one specific job and handle it well. This normally would provide the benefit of maintaining the service easily and isolating errors and making the service more reliable and scalable. The benefits of adopting microservice are obvious. Maintainability. Decouple functions so that each function can be maintained separately which reduces the risk of issue ...

   ADVANTAGE,DISADVANTAGE,MICRO SERVICE     2020-09-05 01:25:05

  5 Lightweight PHP Frameworks For Creating An API

PHP is undoubtedly one of the most popular programming languages that offer a wide range of lightweight frameworks for building basic websites to REST APIs. These frameworks are powerful tools that have the potential to enhance productivity in order to deliver faster results without getting distracted from the best practices of development. Developing REST APIs with plain PHP is a tedious and time-consuming process. In order to sort this out, you only need to hire php developers who have a niche...

   PHP,API     2018-10-22 07:55:34

  Why accessing Java HashMap may cause infinite loop in concurrent environment

HashMap in Java is frequently used to handle key/value pairs. But it is not a good candidate to be used in concurrent environment where ConcurrentHashMap should be used instead. If used in concurrent environment, it may cause lots of unexpected behavior even including make the program getting into an infinite loop situation. To understand how this can happen, let's first discuss how HaspMap works internally. In this post we will use implementation of HashMap before Java 8 as example, Java 8 prov...

   JAVA,HASHMAP,INFINITE LOOP     2020-03-29 01:47:00

  The difference between System.load and System.loadLibrary in Java

When writing code using native library in Java, normally the first step is loading some native library. static{ 　　System.load("D:" + File.separator + "Hello.dll"); } JDK provides two ways to load libraries: System.load(String filename) System.loadLibrary(String libname) This post will try to explain the differences of these two ways. According to Java Doc on System.load(), it has below description. Loads the native library specified by the filename argument. The filename a...

   NATIVE,JNI,JAVA,SYSTEM.LOAD,SYSTEM.LOADLIBRARY     2019-02-05 05:49:28

  Some useful Linux commands for teamwork

A small development team in the intranet will frequently transfer codes, share files. Here are some command we use frequently to release some of our work. They are not applicable to Windows users. 1. Output program execution output through GTalk. Sometimes we may need to send the program execution result and log to teammates for debugging using IM. These outputs are very troublesome to copy and send while in command line mode. So we could have a program called gpipe.py which can put GTalk as a p...

   Linux,NFS,GTalk,HTTP     2013-01-16 04:36:33

  Java Then, Java Now - Looking at the evolution of Java from EE7 to EE9

Java, the programming language developed at Sun Microsystems in the 90s and later acquired by Oracle, is the most common programming environment used today, by developers across the globe. With the diversification of applicability that accompanied the technological boom, Java updates now come as Standard Editions (SE), Enterprise Edition (EE) and Micro Edition (ME). The Java SE contains the core programming logic and platform, used for relatively smaller-scale tasks and academic purposes. Java E...

   JAVA DEVELOPMENT COMPANY     2017-07-05 01:09:28

  Fastjson just fixed a bug which might cause out of memory issue

Fastjson just fixed a bug which might cause service down a few days ago. This bug is caused by some mishandling of special character \x which is an escaped character to indicate hexdecimal number. The impact of this bug would be big if the attacker constructs a malicious data which would cause the service down.  The code which causes the issue is in com.alibaba.fastjson.parser.JSONLexerBase#scanString, when a JSON string is passed in, fastjson would parse the string character by c...

   FASTJSON,ALIBABA,BUG,NEWS     2019-09-07 06:03:49

  Resolve high CPU usage issue caused by file_get_contents in PHP

Sometimes a Linux server which runs Nginx + PHP-CGI(php-fpm) web service may experience sudden system load increase and the CPU usage is around 100% for many php-cgi processes when checking with top command. If this happens, file_get_contents may be the cause if it's used in the PHP script. In lots of web applications, normally there are lots of API requests based on HTTP. Many PHP developers like to use file_get_contents("http://example.com/") to get the API response because it's simple to...

   PHP,FILE_GET_CONTENTS,PHP-CGI     2018-11-09 21:35:00

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