Authentication is a very common feature in everyday life. As shown above, Jack requests the server-side application with an account password and the server-side application needs a module dedicated to authentication to handle this part of the logic. After the request is processed, if JWT Token authentication is used, the server will provide a Token to identify the user as Jack, and if the password is entered incorrectly during the login process, the authentication will fail.
Getting Started with Go WebAssembly
How Golang does data race analysis
Overview Go is popular for its simplicity and great concurrent development experience, but we often write code that has Data Race, but Go can often help us check it out, and this article tries to explain how Go does it. What is Data Race In concurrent programming, a data race may occur when multiple concurrent threads, threads or processes simultaneously read or write to a particular memory area. A data race is when two or more threads access the same shared variable at the same time without reasonable synchronization, and at least one thread is writing to the value of the variable.
Go Development Command Line Program Guide
I recently came across a site on Twitter called “Command Line Interface Guidelines” that brings together philosophies and guidelines to help people write better command line programs. The guidelines are based on traditional Unix programming principles, but updated to “keep up with the times” in the modern context. I haven’t really done a systematic review of how to write command-line interactive programs before, so in this article, we’ll combine the clig guide (which may not be comprehensive) with a guide to writing CLI programs in Go for your reference.
Timestamps in computer systems
This is a brief note to organize the currently known timestamp counting standards for different computer systems. The question of how to express time is an ancient one. In the West, the year of Jesus’ birth was widely used as the “Gregorian calendar”, while in ancient China, people used the “Heavenly Stems and Earthly Branches” method of chronology, using a combination of the ten Heavenly Stems and twelve Earthly Branches, cycling once every sixty years.
Getting Started with IPv6
I don’t want to get into the specific design details of IPv6 technology, I just want to give a brief overview from a user’s perspective. As you know, IPv4 is 32 bits (4 bytes) and has 232 addresses, or 4.2 billion addresses. IPv6 is 128 bits (16 bytes), and there are 2128, or 3.4×1038, or 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses. For IPv4 address, according to the global population of 5 billion and one device per person, it is far from enough, not to mention multiple devices per person, especially in the era of Internet of Things.
Cgroup memory leak causing container not to be created
Sometimes you may find that K8S fails to create a Pod with the following error message. 1 2 3 OCI runtime create failed: container_linux.go:380: starting container process caused: process_linux.go:385: applying cgroup configuration for process caused: mkdir /sys/fs/cgroup/memory/kubepods/burstable/podxxx/xxx: cannot allocate memory: unknown" You can see the same error in the docker logs. 1 2 3 4 5 6 $ journalctl -u docker Mar 20 00:04:33 k8sworker06-new dockerd: time="2023-03-20T00:04:33.461528517+08:00" level=error msg="Handler for POST /v1.
Global variables in Golang
C is one of the ancestors of Go, and Go inherits a lot of C syntax and expressions, including global variables, although Go does not directly give the definition of global variables in its syntax specification, but those who have already started Go know that the package exported variable in Go plays the role of a global variable. exported variables are similar to C global variables in terms of advantages, disadvantages, and usage.
UPS Nut Configuration Tutorial
1. Nut installation Here I use Ubuntu Server 22.04 system, the installation can be done directly with one apt command: 1 apt install -y nut 2. Nut service components Before configuring Nut, we need to understand the components of Nut and their roles. Nut mainly contains three core services: nut-driver: This service is responsible for communicating with the UPS via a specific driver. nut-server: This service uses nut-dirver to communicate with the UPS and to publish the UPS status via web services.
Getting Started with APISIX, the cloud-native API gateway
Apache APISIX is a cloud-native API gateway under the Apache Software Foundation that is dynamic, real-time, and high-performance, providing rich traffic management features such as load balancing, dynamic upstream, grayscale release (canary release), service circuit break, speed limit, defense against malicious attacks, authentication, observability, and more. We can use Apache APISIX to handle traditional north-south traffic, as well as east-west traffic between services. It also supports use as a Kubernetes Ingress Controller.
Using AppArmor to Restrict App Permissions
It is well known that in cloud-native environments, we can control application access to resources in the cluster through RBAC mechanisms, but these are not enough for production environments, where the host is still a security risk when applications have access to host resources (e.g. Linux privilege words, network access, file permissions). For this situation, the Linux kernel security module AppArmor supplements standard Linux user and group-based permissions to limit the application to a limited set of resources and also serves as a protection for the Pod from unwanted attacks.
Redis is unable to schedule Slave after stopping Master node in Sentinel mode
When I manually kill the service at the redis master node, the slave node cannot be scheduled. The slave Sentinel error log is as follows. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 13322:X 16 Mar 2023 05:56:05.855 * Sentinel new configuration saved on disk 13322:X 16 Mar 2023 05:56:05.855 # +vote-for-leader 56633d20baa5b74afdabb4284967c899fa616471 26 13322:X 16 Mar 2023 05:56:05.
Using mobx to take over all state in react
Among react hooks, useEffect is the most commonly used hooks function, but its api experience of manually managing dependency state has been criticized for a long time, and there are countless articles on how to use useEffect properly in the community, but it still doesn’t stop the fact that more newcomers have a hard time using this api properly, which is also jokingly called the react newbie wall. Moreover, react is the only popular web framework that requires manual management of hooks dependencies.
Unit testing is a crucial part of software development, and its existence includes but is not limited to the following aspects. Improving code quality: Unit testing ensures correctness, reliability and stability of code, thus reducing code defects and bugs. Reduce regression testing costs: When modifying code, unit testing can quickly check whether it affects the functionality of other modules, avoiding the cost of regression testing the entire system. Promote teamwork: Unit testing can help team members better understand and use the code written by each other, improving the readability and maintainability of the code.
GPT-4 shock release: large multimodal model, far ahead, top 10% of mock bar exam scores!
We’ve created GPT-4, the latest milestone in OpenAI’s effort in scaling up deep learning. GPT-4 is a large multimodal model that, while less capable than humans in many real-world scenarios, exhibits human-level performance on various professional and academic benchmarks. https://openai.com/research/gpt-4 At 1am today, the Open AI team tweeted the official announcement that GPT-4 is here! GPT-4 will be one of the largest and most powerful language models developed by OpenAI, and OpenAI hopes to improve the language understanding and generation capabilities of GPT-4 by using more training data and higher model parameters.
self vs Self
In the process of learning the swift language, you will constantly find some unbelievable syntax of swift. After learning it, I often ask myself, “Is it really necessary? Before learning it, who would have thought that self and Self are different? Keyword self Scenario 1 Prefix self. The prefix self. is the most commonly used scenario, when the keyword self, similar to the this keyword in other languages, represents the instance of the current code run during the coding process.
Is Go an object-oriented programming language?
Golang has been open source for 13 years, and in the recent TIOBE ranking of programming languages for March 2023, Go once again broke into the top 10, moving up two spots from Go’s ranking at the end of 2022. Many first-time Go developers, many of whom come from the OO (object-oriented) language camp like Java, Ruby, etc., ask the first question they ask after learning Go: Is Go an OO language?
Talking about IaC: Infrastructure as Code
In fact, the concept of IaC has been around for a long time. This article briefly talks about the past, present, and future of IaC. IaC’s Past IaC actually has a long enough history. First, let’s look at the core features of IaC. The end product is a machine readable product. It could be a piece of code, or it could be a preparation file. based on machine readable products, can further rely on existing VCS systems (SVN, Git) to do versioning.
GCC and G++
GCC/G++ is used to compile and link C/C++ programs, long story short, a compiler. Its history is not described here, so those who are interested can check it out for themselves. Compilation process of C/C++ Before introducing GCC/G++, let’s briefly explain the process of compiling and linking C/C++ to generate executable files. Source file preprocessing: c preprocessing (cpp.exe) to process macros in source files, etc. 1 cpp hello.c > hello.i Compile: gcc/g++ compiles the preprocessed code into an assembly program, the -S option indicates the generation of an assembly program file (.
Links & Libraries
Virtual Memory The first thing we need to have a clear idea of what we normally call memory is that what we are talking about is actually virtual memory, not manipulation of real physical memory. On a bare metal machine without an operating system installed, the memory we are dealing with is physical memory. As computers evolved, a program called an “operating system” was installed on the computer, which took over all the hardware resources and provided us with a layer of abstraction.