The Most Efficient Struct Configuration Pattern For Golang
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- čas přidán 3. 05. 2023
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In this Golang tutorial, you'll learn about an efficient configuration pattern in Golang that will help you master complex structures and simplify your code. Discover how to unlock the power of configurable structures in Golang and create mind-blowing patterns to enhance your programming skills.
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Thanks for watching
This pattern is commonly known as the "Functional Options" pattern. The Functional Options pattern is a design pattern in Go where you pass in functions that alter the state of a type. These functions are often called "option functions". They provide a way to cleanly design APIs and offer a more flexible and readable way to interact with a function or type. Nice demonstration on how to implement them. Thanks.
Functional Options Pattern... popularized by Dave Cheney
Any book/reference? Thanks
Surprised gg didn't know the name TBH
@@jamesprendergast7158 because Ant creates his own meta
Looks like functional riff on the builder pattern.
Perfect timing! I am doing something right now that can use this pattern. Thanks!
1. Make the config elements private
2. Make the options type a public interface, with a single private method (apply(config) config)
3. Expose public functions returning this interface
4. Add a function type that complies with the option interface, make that type implement the apply method by calling itself.
5. Add a no-op type for validation when needed.
6. Validate input before returning a config type.
Boom, functional options with a restrictive builder pattern, for your constructors. You can make it generic too.
Hey! Those suggestions are really great, I'm new at Golang and have tried to adapt Anthonygg's example with your suggestions, but I'm a bit stuck at step 5. Could you clarify what you mean? Thanks
Could you create a github example of these ideas ?
This channel is amazing, you're making my Go code better and better for every video!
The way you make any concept understand is just amazing !!
Love these pattern videos man!!
This is a great video. I stumbled onto using this pattern by accident, it was very useful for a previous project I was working on
Thank you for posting this Anthony, very nice pattern and will be trying to incorporate it with my starter projects
Really helpful, you can see the benefit right away! Awesome stuff
Just love this man !! More like this brother, these r the stuff which really play with the Dopamine !!
This is amazing and used in a lot of places tbh. This is very true that it's used in gRPC, also ssh package if I am not wrong because ssh connection has a lot of options. While putting this in a library the "withXYZ" functions can also be a method where it can have the server receiver methods.
This is so so so amazing!!!
Awesome video as always! ❤
Thanks, I think you also talked about a bit of functional programming in Golang in this video, which is very nice.
This is so useful, thank you so much!
Nice one. Really enjoy this pattern.
Thanks for diving into design patterns Anthony ! This is what separate starting devs to more advanced ones, that we all aspire to be, and that is understanding design patterns. Looks more like the Builder pattern than the Visitor one.
Apperantly is the “functional options” pattern 🤷♀️
@@anthonygg_ yes Functional Options Builder pattern !
I also know this as a builder pattern, it's very common and good use for building test fixtures
As always very advanced content
Top notch stuff 👌🏽
Thanks for yours lessons. One of the best video lessons for go.
This is great!
Nice clean pattern to understand too
Reinventing the wheel of named function parameters with default values))
you're free to use a map or whatever my guy
Hi Antonio, how are you? I'm migrating from nodejs to Golang thanks to you and your videos, always amazing! I don't know if it's asking too much, but could you make a video/tutorial for developing web crawlers with golang, please? I was googling about it but I didn't find any good content about it. Thank you so much my friend, you are amazing!
nice pattern, seems very helful
Watch this video for some time ago, remember. And return now to implement this in my project))
Antony is gigachad, thx for the video
I wish you would upload this amazing tutorial when I first learnt Go.
Amazing video, thanks for sharing your knowledge!
Quality Content
🙏
This pattern is so good !!! I guess you can use it in TS/JS too
Beautiful ❤️
Thank you, perfect
Does feel like a take on the builder pattern.
Incredibly handy pattern a lot of Elm libs use as well.
Meanwhile in TypeScript:
mergedOpts = {
...defaultOpts,
...opts
} as Opts
But its a cool pattern. Go doesn't have "map spread operator" and thats a good thing probably. But sometimes it would be so handy to have more syntactic sugar
btw it is a mix of Higher order Functions you write and you use them to compose a struct using Inversion of Control.
So basically Higher order compositional Inversion of Control based state management (as your config acts as a state) 😂😅
Aah functional stuff is just so pleasing to think about
This is a beautiful pattern!
Thanks for the explainer, I'd have been searching docs for a standard way to do this without realising it requires a pattern. In JS I'd just use a default arg param and a spread operator to override
This is pretty cool.
It looks fancy but a bit of a hassle. A simple builder pattern is much more readable I think. The default values are nice. Then just put methods onto the ServerOpts type which return *ServerOpts.
type ServerOpts struct {...},
func NewServerOpts() *ServerOpts {...set defaults...} ,
func (s *ServerOpts) Id(id string) *ServerOpts {... set id ..},
func (s *ServerOpts) MaxConn(maxconn int) *ServerOpts {...set maxcon..}
Then you can use it like this:
s := NewServer(NewServerOpts().Id("my-server").MaxConn(100))
Good stuff. Aws' sdk has this pattern in every client (that I've used).
Hey big boss, two questions:
1. How to make an efficient cron job scheduler from scratch?
2. How to make realtime subscriptions to database values - for example we have key value store but then we build realtime subs that can subscribe to changes of a key and its data?
Another quality video for the fans homie, love this channel.
Bests,
Super fan.
amazing.
very good thx bro
only real world shit in the channel 💪🏼 love your content as always ❤
Isn't this kind of a limitation on the language? If you could specify default values when you declare structs, then this would go from 50 lines down to 10? You mentioned doing this function approach if you were building a library. How would you do this in a way that's easy for consumers of the library to use and know which functions are available to be used for configuration? Would you put them together into a "configuration" package? (I'm not a Go user, just interested)
this language is limited is so many ways that eventually you give up on it and probably on life as well. GO, while being a higher level than C, looks and feels as clunky as C. but what in C is honestly called a hack, in GO called a pattern. C was designed to be as easy to parse and compile as possible and that's why it lacks so much. GO has no such excuse
The example here is for overriding defaults.
Imagine instead a environment specific factory configuration or just a variety of options:
Lets say your server/thingy supports different storage services - S3, ftp, local.
Now you want to say: withStorageDriverFromEnv, or withFtpStorage or withS3 storage.
All of them require different kinds of paths, credentials etc..
Now do that with default values on struct.
The limit is in the example given.
For consumers you provide docs. Or you instead implement the OptFunc as an interface . Then it would be possible to view the list of implementations for given interface(if you have good IDE) .
that was really cool trick i like it
I have misused this pattern. Quite useful
This is honestly really cool, I always hated how there is no way to do kwargs in go
Clever. I like it.
Looks to be a variation of the builder pattern. (I come from OOPS)
Gem....amazing explanation..and going sub ..
3:50 to 3:53 Witch Craft and Woo Doo ! . My man's a part-time wizard
That's a beautiful pattern
Great work around. Though I would not use it, as I cannot use an existing config to initialize the state. Instead I would just use merge function to join default config with provided config.
oh snap cool man
Is there an advantage over the builder pattern? It seems to be equivalent in usage but I'd guess harder to optimise.
this is unbelievable
Opts
(Opts, opts), opts
Opts
Opts opts😅
Thank you Op for the video ; I appreciate your talent and time
Cool approach! Just wondering, why did you go back to VS Code?
I guess this could also be combined with builder pattern, and then you can just can chain those withX on the builder and build will return the instance
This pattern is just an adptation from the Fluent Interface Pattern existing in OOP languages, is nice to see it in go though.
This was really informative.
A side question. Any particular reason for using int instead of uint in maxConn?
I noticed most people use int where a uint makes more sense. In this case, we cannot have negative maxConn.
Just for demonstration purposes. Uint is better.
@@anthonygg_ Thanks.
I think somewhere I heard something along the lines of integer underflow and was wondering if this has something to do with that
-1 meaning unlimited could be an option in that case though :)
how inner function (the one that you retuen in options functions) gets the pointer which it has as input when higher lexical scope doesnt provide it
This is a good pattern, I've been using it for years, but why not make an option function that returns the same option function with the previous value? That way you can change and reset options on the fly. An example could be to elevate debug logging temporarily for some very complex code segment. Rob Pike wrote an article about this for some years ago.
type Option func(*Some) Option
type Some struct{
...
dLevel int
}
func Debug(d int) Option {
return func(s *Some) Option {
t := s.dLevel
s.dLevel = d
return SetOption(t)
}
}
The only problem with this pattern is that you lose info from the LSP. Working with the AWS SDK, I often have no idea what is possible or what the opt functions do without reading the documentation. It’s a trade off, especially when you have a lot of config options
I think it is possible to solve by putting all 'OptFunc's into another (child) package, e.g. "server/opts". Maybe it's a bit of overkill but if you then type 'opts.' and call autocompletion it will list all 'OptFunc's
You write: "I often have no idea what is possible or what the opt functions do without reading the documentation." But is a classic config struct any better, in this respect?
@@jub0bs of course its better, you got one place/struct to check all the possible options
@@jurijskobecs2803 The fields of a struct type tell you close to nothing about how they're going to be used by the rest of the program. Their names give you clues at best, and their documentation is meant to give you accurate information. But you'll need to dig into the implementation to definitely find out. In this respect, a struct isn't superior or inferior to functional options.
It is called 'Functional options pattern'
We use to call this the Option pattern. Would you have a nice one for Mandatory config where you cannot provide a reasonable default, like a sql.Conn?
Thats an amazing question! You could force an interface as option and implement a noop for that interface as default to prevent nil pointers. What do you think?
@@anthonygg_ i see the Idea, but i am looking for a way for large amount of mandatories, noop wont do the trick i think
It is called 'Functional options pattern' should look like this:
func NewServer(addr string, opts ...Option) error () {.....}
so here addr is mandatory.
Usage example:
server, err := NewServer("localhost",
withPort(8080),
withTimeout(time.Second))
👍
Interesting
I think it's a Go version of the Builder pattern, but not sure.
It's like Visitor pattern, but in a functional way
AWS SDK uses this pattern too.
why not create a builder pattern, which will do the same as what you are doing, with more readability.
Can you share example how your pattern is more clear than the one shown in a video ?
@@JohnDoe-ji1zv wouldnt it be more readable this way newServer().withTls().withId().withMaxConnections().build()
I was thinking about the same thing. 🤔 Maybe the authors or some other people would like to chime in.
Hi Anthony, what theme do you use?
Gruvbox
will this thing not make established Go features convoluted? aren't you not reinventing the wheel here?
Is this pattern used in go starndard lib?
What is the advantage of this pattern over a builder pattern?
Error handling
In go you cannot chain builder calls as each must return error (and not this)
@@sfsdeniso5941 thanks for the answer! However I think a builder for the opts struct shouldnt have this problem, but now I can see the inconvenience. Maybe a walk around could be that the builder struct could itself carry through the error as a property and the build method could return the value error tuple
Start: 1:03
Cool fancy< stuff. What about toi make a fluent api with that style?
docker compose v2 uses this pattern
This is essentially a builder pattern written in Go.
That looks like function as parameter that was introduced in java 8 with lambdas xD
Hello. Where does download your vscode config?
This is like a functional builder pattern...?
Can somone please rephrase what's happening at 6:15 with fn(&o) ? It's not clear to me how everything works together
He's using the spread operator to allow as many OptFunc's as you want. He then uses the range operator to loop through each OptFunc and executes them with a reference to the options struct (that's the **fn(&o)**), so that the OptFunc can modify the options directly, overwriting the default options.
The only problem i have with this pattern is that it is not obvious which methods/func you can use as options.
Looks like some sort of builder pattern
This looks very oop
Why not just take configuration data from a JSON file, like config.json?
Go can easily resolve this issue by providing the option of built in default parameters similar to Python during the definition of the function
I did something with this .... But my approach was quite different,
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I think I have seen this pattern in google youtube package
Yup!
Why not just make your config a .yaml file and parse it into a Config struct? Then you give your library users a defaults.yaml and they can copy and modify it at their will?
I'll be honest. The accent makes it a little hard for me to understand you at times; HOWEVER, your content is SOO VALUABLE that I don't mind rewatching parts a few times to get better at Go.
I try my best. Thanks man! ❤
@@anthonygg_ you're killing it my dude! great stuff!
I think more easier like this one below
```go
type Config struct {
Env "string"
}
func getConfig() (config Config){
env, ok := os.LookupEnv("ENV")
If !ok{
env = "your default value of ENV here"
}
config.Env = env
return
}
type Data struct {
pool *pgxpool.Pool
}
func NewData(pool *pgxpool.Pool) (*Data, error) {
if pool == nil {
return nil, errors.New("no pool ready")
}
return &Data{
pool: pool
}, nil
}
func main(){
config := getConfig()
data, err := NewData(config.Env)
}
```
I wish golang will add a feature where we can add default parameter value. I feel like this is too much just to do optional parameter stuffs.
I feel you.
the ‘…’ is called variadic.