When using AWS SAM it is possible to call your local lambdas using the AWS SDK, just as you would lambdas running in AWS. I found this very useful when building acceptance tests that would work on local as well as against our AWS staging environment.
To do it, just run sam local as a service on a specific port:
sam local start-lambda -p 8035
Then you can run your code which calls the lambda.
Git is the perfect source control for my home projects. It is free, works on mac, linux and windows, makes it easy to share code through github and takes me out of my Microsoft technology comfort zone. Here are the basic commands I need to be productive.
Adding all changed files in the current directory to the commit:
git add .
Adding any deleted files in the current directory to the commit:
React is made of ....
React maintains it's own hierarchy of react elements. React elements are plain javascript objects instead of DOM objects, so they are very light-weight and fast to process. React keeps the real DOM elements in sync with the react DOM. When something changes, React compares the new components with the current ones and only re-renders the components that have changed.
A React component will start with a root element that exists somewhere inside a HTML document. Everything under that element will be controlled by the React DOM.
const element = Hello, world;
Check to see what output encoding your console has, to make sure the output of your apps don't end up encoded as Ascii.
> $OutputEncoding
IsSingleByte : True
BodyName : us-ascii
EncodingName : US-ASCII
HeaderName : us-ascii
WebName : us-ascii
WindowsCodePage : 1252
| const { toMatchImageSnapshot } = require('jest-image-snapshot'); | |
| const path = require('path'); | |
| const fs = require('fs'); | |
| var gm = require("gm").subClass({imageMagick: true});; | |
| jest.setTimeout(15000); | |
| expect.extend({ toMatchImageSnapshot }); | |
| const imageAtTestPath = path.resolve(__dirname, '11c429f0-8bee-4c86-ab17-e04cf2bd2e11.jpeg'); | |
| const pngAtTestPath = path.resolve(__dirname, '11c429f0-8bee-4c86-ab17-e04cf2bd2e11.png'); |
We have a process that spawns lots of lambdas that we were worried might hit a concurrency limit. We wanted to know what a step function would do in that situation because the AWS documentation says that poll-based services have a built-in retry mechanism if lambdas are throttled and we were hoping that the subsequent steps would simply wait until there was enough capacity.
So I built a step function with three steps that had a sleep in them, and then set the reserve concurrency to 1 for the middle step. Then I kicked off three step functions at the same time.
The result was the second intance of the step function failed on the throttled lamda with the error message: "Lambda.TooManyRequestsException"
There are retry options in step functions, but it is interesting to know that they don't wait for a lambda slot to be available.
| // sleep the function for 5 seconds | |
| function sleep (time) { | |
| return new Promise((resolve) => setTimeout(resolve, time)); | |
| } | |
| // Usage! | |
| await sleep(5000); |
Exif rotation in browsers is a journey of disappointment. The definitive guide on the history of it is quite an interesting read. There's also a current state of the world round-up written in 2012, which is pretty much still the same in 2019.
Firefox supports a CSS attribute that tells the browser to respect exif rotation, but no other browser respects it. There's been a Chrome ticket open to fix it for about five years now.
This is a little proof of concept to try to fix the issue with CSS transforms. We didn't end up using it because we had the images in other elements that were already rotated themselves, so we felt like this would probably cause more problems than it solved. But who kn