I had been working on a client project where I built the GraphQL backend for a new social network using primarily AppSync, Lambda and DynamoDB. One of the features of the app was to support private messaging between two users. To allow either user to fetch their chat messages in chronological descending order, I modelled …
AppSync: how to compare strings lexicographically in VTL Read More »
Hi, welcome to another weekly update. Production-Ready Serverless workshop goes virtual! Starting from May 4th, I will be running a 4-week instructor-led workshop that teaches you everything you need to know to build a production-ready serverless application. It’s based on the same demo app as my Manning course, but all the code has been completely …
TL;DR To make an AppSync DynamoDB resolver throw exceptions on conditional check errors, we need to check $context.error in the response mapping template ourselves. Like this: #if ( $ctx.error ) #if ( $ctx.error.type.equals(“DynamoDB:ConditionalCheckFailedException”) ) $util.error(“your error message”) #else $util.error($ctx.error.message, $ctx.error.type) #end #end $utils.toJson($context.result) And now, the longer version. The problem AppSync lets us perform DynamoDB …
AppSync: how to error on DynamoDB conditional check failures Read More »
Have you been wondering about serverless but just don’t know how and where to start? Maybe you’re already building stuff with serverless, but don’t know if you’re doing it right? Are you unsure about the best practices for testing, monitoring and how to choose between similar services like SNS and EventBridge? I have just …
Skill up your serverless game with my new instructor-led online workshop Read More »
So you have built a serverless application, that, amongst other things, lets you upload images and files to S3. The set-up is very simple: API Gateway, Lambda and S3. It took you no time to implement and it works like a dream. You pat yourself on the back for another job well done. Until one …
Hit the 6MB Lambda payload limit? Here’s what you can do. Read More »
Whilst working on a client project, I ran into an interesting problem with AppSync which I couldn’t find an answer after a lot of googling. I hope this article can save you the same pain should you run into the same problem. The problem is that when you have a nullable nested field that you …
AppSync: skipping nullable nested resolvers by returning early Read More »
Hi, welcome to another weekly update. I teamed up with Furnace First, some personal news. I have joined the advisory board for furnace.io and am working closely with Danny Waite and John Blamire. We’re building a platform for data-intensive applications that can operate at a fraction of the cost of other platforms such as Zapier …
Lambda invocations are charged in 100ms blocks of execution time. But the cost per 100ms of execution time depends on how much memory you allocate to the function. The higher the memory, the more CPU cycles and network bandwidth, but the higher the cost as well. One of the simplest and most efficient cost optimization …
How to: optimize Lambda memory size during CI/CD pipeline Read More »
In this two-part conversation on Real-World Serverless, I spoke with Joe Emison about his experience with serverless and his latest venture, Branch, a home and auto insurance company that is built fully-serverlessly by a small team. Joe is easily one of the smartest people working with serverless technologies today and I’m very grateful that he …
Real-World Serverless: fully-serverless insurance company with Joe Emison Read More »
In the first-ever episode of Real-World Serverless, I spoke with Ricardo Espirito Santo about the state of serverless adoption at Zoopla – how they’re using serverless, their experience with it so far, and the challenges they have faced. Zoopla is a UK company in the real estate industry. They were founded in 2008 and their …
Real-World Serverless: state of serverless adoption at Zoopla Read More »
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