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  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

  The Go Pointer Magic

Go is a language with the pointer type, by which we can Pass pointer into a function and update value in-place. Add methods to a struct as (* T) A, which is different from (T) A(). However, the pointer is type-safe in Go, meaning that there are such restrictions of the pointer. Different types of pointers are unconvertible. Pointer type cannot be used for calculation. Pointer types cannot be compared, either == nor !=. No mutual assignment between different pointer-...

   GOLANG,POINTER,UNSAFE     2021-10-03 02:18:57

  Understand diff in Unix

diff is an important tool program in Unix. It is used to compare differences of two files, it is the foundation for code version control. If you type : $ diff <file_before_change> <file_after_change> diff will tell you what's the difference between these two files. The result may not be so easy to understand, so now I will show you how to understand diff. 1. 3 formats of diff diff has 3 formats due to historic reasons. normal diff context diff unified diff 2. Demo files For easy d...

   diff,Unix,version control,git     2012-09-03 10:49:36

  Implement struct no copy in GoLang

There is some case where some of the struct in GoLang which is not meant to be copied. For example, sometimes a global configuration which should have only one version passed around the whole application and should not be copied and modified. In GoLang, there is no intuitive solution on preventing copying of struct. But there is still some way which can be leveraged to help prevent this while developing the code. The trick is to define some struct implementing sync.Locker interface and has this ...

   GO VET,NOCOPY,NO COPY     2020-09-04 22:24:58

  Use Delve to debug GoLang program

If you don't know how to debug program, you are not a real programmer. gdb can be used to debug go program, but according to golang website, delve is a better option.   Note that Delve is a better alternative to GDB when debugging Go programs built with the standard toolchain. It understands the Go runtime, data structures, and expressions better than GDB. Below is a simple go program. package main type Person struct { Name string Age int } func main() { var me Person me.Nam...

   GOLANG,DEBUG,DELVE     2018-11-09 23:28:43

  How to enable developer mode on Huawei

As a developer, there might be some need to fake locations when developing and testing mobile apps for different countries. Lots of the times some fake GPS apps will be used and they will ask to enable mock location access on the device before allowing you to fake GPS. To achieve this, we first need to have developer mode enabled. In this post, we will show how the developer mode can be enabled and disabled on Huawei devices. Go to Settings, find About phone and open it. You should be able to se...

   ANDROID,HUAWEI,DEVELOPER MODE,DEVELOPER OPTIONS     2020-08-15 21:22:29

  How to monitor user behavior in webpage

Sometimes there is a need for website owners to monitor user behavior on the site so that they can know what pages are mostly visited and which parts are more popular so that they can provide better service to their users. These behavior usually contain user clicks, user mouse over events etc. These data can be sent back to server when triggered with some meta data. In this post, we will cover a few ways to monitor user behavior on a web portal and send data back to backend sever. 1. Synchronous...

   HTML,BEACON API,PING,USER BEHAVIOR     2019-06-29 06:06:59

  Go 1.16 is released

Note: The post is authorized by original author to republish on our site. Original author is Stefanie Lai who is currently a Spotify engineer and lives in Stockholm, original post is published here. Last week, Go1.16 was released, bringing relatively more changes than version 1.15, which was influenced by the epidemic. The update is in many aspects, including compilation, deployment, standard library, etc. In the official Go document, all changes are classified based on Too...

   GOLANG,GO1.16,NEW FEATURES     2021-02-26 21:08:42

  Turn on SecurityManager in Java

SecurityManager in Java is to check whether the application codes can access some restricted resource such as file, socket etc. This can be used in applications which have high security requirements. With this feature turned on, our system resources can be secured with only permitted operations. When JVM starts, it will first check whether the SecurityManager is on by checking the system property java.security.manager, if it's on, then an instance of SecurityManager will be created and it can be...

   SecurityManager,enable,program     2013-12-16 05:03:53

  Fix 'this authentication plugin is not supported' issue while using Go to connect MySQL 8

MySQL 8 has changed its default authentication plugin from mysql_native_password to caching_sha2_password to improve its security. However many third party libraries seem act slowly to catch up with this change. This causes some compatible issues with their connection to MySQL. One of the issues is seen in Go libraries while it's trying to connect to MySQL 8. The specific error has been observed is "this authentication plugin is not supported". The root cause of this issue is that the go-sq...

   MYSQL,GO,MYSQL 8,AUTHENTICATION PLUGIN     2018-07-11 08:55:02

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