Since some time apt-key is deprecated and lot of Ubuntu 22.04 based systems throws the following warning:
Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details You can easily fix this by properly installing Docker and Kubernetes apt archives public keys:
Go has very rich standard library which also contains database/sql module with generic interface over SQL databases. Further, lib/pq PostgreSQL driver is fully compatible with database/sql and provides all basic database operations. However, since this is generic implementation over all supported databases, using it is a trade-off not supporting some PostgreSQL specific features. Fans of PostgreSQL (in further text pg) may want more and here comes pgx in help. pgx is a very rich pg driver supporting LISTEN / NOTIFY, COPY, type mapping between pg and Go, all specific pg types, wire protocol and much more.
Go is over ten years old language but generics (type parameters) are introduced just in the March this year. Hence, still lot of developers avoid using them or have certain problems once decided to give it a try. One of the common problems is how to check the concrete type of a generic parameter, specially of non constrained parameters. So, if you try to do the following, it won’t work:
Lot of the tutorials on the Web show different ways of writing Go HTTP middlewares, but most of them use functional approach meaning using functions that get dependencies as parameters and return HTTP handler function or handler. There is nothing wrong about this, but it can be quite messy to write a complex middlewares like database based authentication and authorization or simply middlewares which have lot of dependencies. In this article I am going to explain how to use more object oriented way of writing such middlewares. Let’s start with the basic object oriented middleware example:
In the previous blog post I described how to define GitHub Actions pipeline to benefit from caching Rust dependencies and container images’ layers. But the final result may also depend on your Dockerfile. Namely, Docker Buildx Action supports BuildKit and buildx and in order to benefit from this, your Dockerfile has to explicitly cache layers. Actually, this is quite easy to achieve, let’s see the example:
If you are running default kernel with your Ubuntu or Linux Mint installation, you probably won’t face this problem during kernel updates because all packages are coming from the official distribution sources. However, if you like to run the newest Linux kernels and update them using mainline kernel installer, you may get warning possible missing firmware during the installation.
Rust is a great programming language, but it’s compiler is known to be slow. The main reason is that it checks so many things during the compilation in order to provides memory and concurrency safety. Like in many other cases, pipelines may be speeded up by caching, but it is very important to set the caching properly, otherwise it won’t help. Besides compiling your code may be slow, you also may want to use some cargo tools to lint and check your code and this will require to be compiled as well, if you don’t want to download binaries. Some popular tools are:
Few days ago Go 1.18beta1 was released and with it the first official generics support. I was embarrassed with standard Go’s HTTP handler functions for quite a while. If you are not familiar with Go, you probably wonder why, but if you are familiar, I believe you know. For example, implementing a RESTful API using idiomatic Go requires lot of code repetition in order to JSON decode request bodies and JSON encode response bodies. This problem was possible to solve in some way but never in such elegant way like using generics.
Most of the date and time related crates like time or chrono already implement serde traits making date or datetime parsing quite easy. This applies just if the format is standard, but what happens if the format is not standard? Let’s say we want to parse datetime looking like this 2021-10-24T07:48:26.389646Z. There is no timezone information so I decided to try the PrimitiveDateTime type from time crate. I didn’t consider using chrono at the moment because of the RUSTSEC-2020-0159 problem.
Go is very attractive language for microservices’ development, but using acim/go-reflex image and docker-compose you can run multiple microservices including your gateway on your local machine. This image can run virtually any Go server based application and also reacts on changes in the code and recompiles the binary on the fly. If you want to debug your microservices’ stack or develop a new feature where you have to touch multiple services, this is very good tool to do so. Let’s take a look at the docker-compose stack example:
