Update your CRDs with confidence Hello. I would like to write about a release for crd-to-sample-yaml1. It’s the release version v0.8.02. This version brings with it a feature to test the validity of your CRD changes. It means that if you change your CRD it will test if the changes do not break working samples of that version. This is achieved by a helm unittest type of YAML based test scenarios and snapshot generation. ...
Hello. Today’s will be a quick post. Everyone knows and loves/hates functional options1 in Go. The biggest gripe people get with it is, that the options aren’t discoverable and that there is no IDE support for nicely auto-completing options. My thought about this was that, what if we would just hang it on a struct? Let’s see how that looks. Consider this normal server builder with options: type Server struct { Name string Address string Port int } func WithName(name string) ServerOptFn { return func(s *Server) { s.Name = name } } func WithAddress(address string) ServerOptFn { return func(s *Server) { s.Address = address } } func WithPort(port int) ServerOptFn { return func(s *Server) { s.Port = port } } type ServerOptFn func(*Server) func NewServer(opts ...ServerOptFn) *Server { s := &Server{} for _, o := range opts { o(s) } return s } Now, what if you would like to retain the niceness of the clean options pattern where you don’t have to specify and empty struct but still could use a struct to gather the options together? ...
Hello! Just wanted to give an update to my crd-to-sample-yaml tool. It, now, supports creating a standalone HTML output. Why, you may ask? Well, now you can host the generated content as a static page on your website. That’s pretty handy. Here is a sample output: Go and get it while it’s hot in version v0.4.0. That’s all. Thanks for reading!
Generic dig for map key using typed parameters Hello! I was fiddling with a way of getting out values from a map that is of format map[string]any. But I wanted my type safety as well. This was coming from digging out keys from a Metadata field. The metadata was in a JSON format. This is what I came up with: / FetchValueFromMetadata fetches a key from a metadata if it exists. It will recursively look in // embedded values as well. Must be a unique key, otherwise it will just return the first // occurrence. func FetchValueFromMetadata[T any](key string, data *apiextensionsv1.JSON, def T) (t T, _ error) { if data == nil { return def, nil } m := map[string]any{} if err := json.Unmarshal(data.Raw, &m); err != nil { return t, fmt.Errorf("failed to parse JSON raw data: %w", err) } v, err := dig[T](key, m) if err != nil { if errors.Is(err, errKeyNotFound) { return def, nil } } return v, nil } func dig[T any](key string, data map[string]any) (t T, _ error) { if v, ok := data[key]; ok { c, k := v.(T) if !k { return t, fmt.Errorf("failed to convert value to the desired type; was: %T", v) } return c, nil } for _, v := range data { if ty, ok := v.(map[string]any); ok { return dig[T](key, ty) } } return t, errKeyNotFound } The interesting part is the dig method and the type assert to the desired part. Calling this with something like: ...
CRD to YAML as WASM website A while ago, I wrote about Generating Sample YAML files from CRDs. It’s a tool I created that lives here. It has a front-end service as well for convenience. I wrote it in a traditional client-server manner. It’s running from a Docker Swarm container. But, as I was thinking about it, nothing in this service requires interaction with a server. It gets some user input, processes it, and has some output. I could have written it in plain Javascript. But, since I don’t know JavaScript, or don’t know it well enough, and I do know GO, and I wanted to become more familiar with WASM, this was the perfect learning opportunity. ...
Intro Welcome. This is a longer post about how to deploy a Go backend with a React frontend on Kubernetes as separate entities. Instead of the usual compiled together single binary Go application, we are going to separate the two. Why? Because usually a React frontend is just a “static” SPA app with very little requirements in terms of resources, while the Go backend does most of the leg work, requiring a lot more resources. ...
Intro Hi folks. This time, I would like to talk a little bit about code reviews. How do you do code reviews? Don’t hesitate to share it in the comments. How do I do code reviews? Well read on if you would like to know. The Top Down approach If I’m dealing with a small code change, a couple of lines here and there in the odd file first, I’ll try to understand why the review is there? What was it trying to achieve? What’s the goal of the change? Is there a ticket/issue I can read for background info? Or an RFC? ...
Intro Hi folks. Today I would like to share a quick “fix” for a problem I’ve seen popping up here and there. That is, if you have a react frontend which is a SPA app but you still want refresh to work. What do I mean by that? Consider the following… The problem You have a SPA app with a react router which navigates the user around. The app calls to a backend api which serves content of some kind. You have the following routes…. login, signup, reset, archive. ...
Intro Hi folks. So there is this workshop from Dave Cheney. And I thought I’d draw a sort of summary of that workshop. Right-click->Open Image for higher resolution. Cheers, Gergely.
Intro Hi folks! Today I would like to write about a metric that I read in a book called Clean Architecture from Robert Cecil Martin ( Uncle Bob ). Abstract The metrics I mean are Efferent and Afferent coupling in packages. So you, dear reader, don’t have to navigate away from this page, here are the descriptions pasted in: Afferent couplings (Ca): The number of classes in other packages that depend upon classes within the package is an indicator of the package’s responsibility. Afferent couplings signal inward. (Affected by this package) (Fan-In). ...