Apple finally opens iPhone’s NFC chip. With iOS 11, apps on iPhone 7 and iPhone 7 plus can read NFC tag using Core NFC. (Writing is not…

This article introduces how to debug code (logic) and GUI of React Native apps. Originally it was the talk I made at a React.js/React Native meetup in April 2017. (This article was updated on Mar 17, 2018.) “A great software developer must be a great debugger.” The beginners all have…

This post shows how I implement a progress tracker (progress bar, progress indicator) in React Native and the lessons I learnt. First version At the beginning, the design is like this. There are two buttons. There is an arrow between them.

Profiling memory usage of a Go app net/http/pprof is a powerful package for profiling. This video introduces how to use it to do memory profiling. Let me write down the steps. Import the package in your go web project (it doesn’t have to be a web app). Just add this…

I created a docker container for a golang app, based on debian 7 image. Everything works well until it visits https. The error is x509: failed to load system roots and no roots provided. I thought there might be something that should be configured for golang. But actually, it is nothing about golang. It’s about SSL certificates. For debian, /etc/ssl/certs/ca-certificates.crt is the root certificates. But the offical debian 7 image does not contain it. Installing ca-certificates via apt-get solved the problem. (You can manually copy /etc/ssl/certs/ca-certificates.crt from another linux OS too.)

When you build Docker images many times, you will find it is very necessary to manage images with tags. If you build an image without a tag, the default tag ‘latest’ is created automatically. docker build -t company/myimage . The complete name is company/myimage:latest When you need to update a new version of company/myimage, you don't need to create an image company/myimage_v2. You should create an image with the same name and a new tag.

Recently I deployed my node.js app, Redis, Postgres, Nginx with Docker and wrote a tutorial. I want to share you with some tricks and tips about Docker. Choose Debian as the base image. Debian image is much smaller than other OS images. It is recommended in Docker’s official best practices. A problem is the packages in…

In the previous tutorial, I show you how to deploy a web app, Redis, Postgres, Nginx with Docker. This post shows you how to restore and backup Postgres database which is running in a Docker container. You can get all source code at https://github.com/vinceyuan/DockerizingWebAppTutorial. I use pg_dump to dump a…

This tutorial introduces how to deploy a web app, Redis, Postgres and Nginx with Docker on the same server. In this tutorial, the web app is a node.js(express) app. We use Redis as a cache store, Postgres as the database, and Nginx as the reverse proxy server. …