You can become a serverless blackbelt. Enrol to my 4-week online workshop Production-Ready Serverless and gain hands-on experience building something from scratch using serverless technologies. At the end of the workshop, you should have a broader view of the challenges you will face as your serverless architecture matures and expands. You should also have a firm grasp on when serverless is a good fit for your system as well as common pitfalls you need to avoid. Sign up now and get 15% discount with the code yanprs15!
Suppose you want to merge an assembly A (AssemblyA.dll) with another assembly B (AssemblyB.dll) with ILMerge into a merged assembly (Merged.dll), and everything works fine until the user of your merged assembly also references that AssemblyB.dll, at which point that user will get Ambiguous reference errors for any reference to types defined in assembly B, for example:
Understandably the compiler is not happy here because it finds duplicated definitions for TypeB under the same namespace in the two versions of the assembly B (the one referenced in the user’s project and the one that’s merged with assembly A).
So how do we get out of this unholy mess?
Well, there’s this little known feature in .Net called extern alias which allows you to give referenced assemblies an alias via that little Aliases property in the Properties window for any referenced libraries (one I’m sure we have all seen countless times and wondered what it means).
By default the alias for an assembly is ‘global’, which just means global namespace, but you can change it via the Visual Studio properties window or via command line options to CSC.exe:
Now the types defined in the Merged.dll assembly will fall under the Merged namespace and to access them you need to first add a line to your code:
extern alias Merged;
and then anywhere you’re referencing types from the Merged assembly you need to prefix it with Merged:: like the following.
You might also want to give AssemblyB an alias just to remove any reasonable doubt which assembly a type comes from whenever you reference a type defined in AssemblyB.
Whilst this is a way to get you out of a tight spot, it’s far from a clean solution, and as @BjoernRochel said below, a good general advice is to not merge assemblies that you do not own to begin with:
Hi, I’m Yan. I’m an AWS Serverless Hero and I help companies go faster for less by adopting serverless technologies successfully.
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.
Skill up your serverless game with this hands-on workshop.
My 4-week Production-Ready Serverless online workshop is back!
This course takes you through building a production-ready serverless web application from testing, deployment, security, all the way through to observability. The motivation for this course is to give you hands-on experience building something with serverless technologies while giving you a broader view of the challenges you will face as the architecture matures and expands.
We will start at the basics and give you a firm introduction to Lambda and all the relevant concepts and service features (including the latest announcements in 2020). And then gradually ramping up and cover a wide array of topics such as API security, testing strategies, CI/CD, secret management, and operational best practices for monitoring and troubleshooting.
If you enrol now you can also get 15% OFF with the promo code “yanprs15”.
Check out my new podcast Real-World Serverless where I talk with engineers who are building amazing things with serverless technologies and discuss the real-world use cases and challenges they face. If you’re interested in what people are actually doing with serverless and what it’s really like to be working with serverless day-to-day, then this is the podcast for you.
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!
Check out my video course, Complete Guide to AWS Step Functions. In this course, we’ll cover everything you need to know to use AWS Step Functions service effectively. There is something for everyone from beginners to more advanced users looking for design patterns and best practices. Enrol now and start learning!
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.
- All you need to know about caching for serverless applications
- 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?
- Check-list for going live with API Gateway and Lambda
- How to choose the right API Gateway auth method
- CloudFormation protip: use !Sub instead of !Join
- AWS Lambda – should you have few monolithic functions or many single-purposed functions?
- Guys, we’re doing pagination wrong
- Top 10 Serverless framework best practices
- How to break the “senior engineer” career ceiling
- My advice to junior developers