Check out my new course Learn you some Lambda best practice for great good! and learn the best practices for performance, cost, security, resilience, observability and scalability.
One of the pitfalls with LINQ which I have fallen into on multiple occasions is around the use of the OfType<T> extension method with dictionaries.
Either through carelessness or changes to the underlying variable (a class property being changed from list to dictionary for instance) I have ended up using OfType<…> on a dictionary which compiles fine but unless I’m specifically looking for KeyValuePair<TKey, TValue>, it’s not going to behave as I’d expected…
Curiously, however, with most other IEnumerable<T> types Resharper is able to spot the danger signs and give me a warning:
Turns out Resharper has a really nice feature – Custom Patterns – which I hadn’t been aware of until recently, that allows you to specify your own patterns which can then trigger suggestions/warnings/errors etc. when matched against elements of your code. I can now create a custom pattern to find places where I have tried to use the OfType<T> extension method against a dictionary, like the following:
Now, if we go back to the source code, you can see that Resharper has now picked up on my mistake using my pattern:
and since we specified a Replace pattern above we can even use the Resharper helper to quickly fix our code!
I specialise in rapidly transitioning teams to serverless and building production-ready services on AWS.
Are you struggling with serverless or need guidance on best practices? Do you want someone to review your architecture and help you avoid costly mistakes down the line? Whatever the case, I’m here to help.
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Check out my new course, Learn you some Lambda best practice for great good! In this course, you will learn best practices for working with AWS Lambda in terms of performance, cost, security, scalability, resilience and observability. We will also cover latest features from re:Invent 2019 such as Provisioned Concurrency and Lambda Destinations. Enrol now and start learning!
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Here is a complete list of all my posts on serverless and AWS Lambda. In the meantime, here are a few of my most popular blog posts.
- Lambda optimization tip – enable HTTP keep-alive
- You are wrong about serverless and vendor lock-in
- You are thinking about serverless costs all wrong
- Just how expensive is the full AWS SDK?
- Many faced threats to Serverless security
- We can do better than percentile latencies
- Yubl’s road to Serverless
- AWS Lambda – should you have few monolithic functions or many single-purposed functions?
- AWS Lambda – compare coldstart time with different languages, memory and code sizes
- Guys, we’re doing pagination wrong
- Top 10 Serverless framework best practices