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xuu
txt.sour.is
 (2y ago)
↳ In-reply-to » Progress! so i have moved into working on aggregates. Which are a grouping of events that replayed on an object set the current state of the object. I came up with this little bit of generic wonder.

(cont.)

Just to give some context on some of the components around the code structure.. I wrote this up around an earlier version of aggregate code. This generic bit simplifies things by removing the need of the Crud functions for each aggregate.

Domain Objects

A domain object can be used as an aggregate by adding the event.AggregateRoot struct and finish implementing event.Aggregate. The AggregateRoot implements logic for adding events after they are either Raised by a command or Appended by the eventstore Load or service ApplyFn methods. It also tracks the uncommitted events that are saved using the eventstore Save method.

type User struct {
  Identity string ```json:"identity"`

  CreatedAt time.Time

  event.AggregateRoot
}

// StreamID for the aggregate when stored or loaded from ES.
func (a *User) StreamID() string {
	return "user-" + a.Identity
}
// ApplyEvent to the aggregate state.
func (a *User) ApplyEvent(lis ...event.Event) {
	for _, e := range lis {
		switch e := e.(type) {
		case *UserCreated:
			a.Identity = e.Identity
			a.CreatedAt = e.EventMeta().CreatedDate
        /* ... */
		}
	}
}
Events

Events are applied to the aggregate. They are defined by adding the event.Meta and implementing the getter/setters for event.Event

type UserCreated struct {
	eventMeta event.Meta

	Identity string
}

func (c *UserCreated) EventMeta() (m event.Meta) {
	if c != nil {
		m = c.eventMeta
	}
	return m
}
func (c *UserCreated) SetEventMeta(m event.Meta) {
	if c != nil {
		c.eventMeta = m
	}
}
Reading Events from EventStore

With a domain object that implements the event.Aggregate the event store client can load events and apply them using the Load(ctx, agg) method.

// GetUser populates an user from event store.
func (rw *User) GetUser(ctx context.Context, userID string) (*domain.User, error) {
	user := &domain.User{Identity: userID}

	err := rw.es.Load(ctx, user)
	if err != nil {
		if err != nil {
			if errors.Is(err, eventstore.ErrStreamNotFound) {
				return user, ErrNotFound
			}
			return user, err
		}
		return nil, err
	}
	return user, err
}
OnX Commands

An OnX command will validate the state of the domain object can have the command performed on it. If it can be applied it raises the event using event.Raise() Otherwise it returns an error.

// OnCreate raises an UserCreated event to create the user.
// Note: The handler will check that the user does not already exsist.
func (a *User) OnCreate(identity string) error {
    event.Raise(a, &UserCreated{Identity: identity})
    return nil
}

// OnScored will attempt to score a task.
// If the task is not in a Created state it will fail.
func (a *Task) OnScored(taskID string, score int64, attributes Attributes) error {
	if a.State != TaskStateCreated {
		return fmt.Errorf("task expected created, got %s", a.State)
	}
	event.Raise(a, &TaskScored{TaskID: taskID, Attributes: attributes, Score: score})
	return nil
}
Crud Operations for OnX Commands

The following functions in the aggregate service can be used to perform creation and updating of aggregates. The Update function will ensure the aggregate exists, where the Create is intended for non-existent aggregates. These can probably be combined into one function.

// Create is used when the stream does not yet exist.
func (rw *User) Create(
  ctx context.Context,
  identity string,
  fn func(*domain.User) error,
) (*domain.User, error) {
	session, err := rw.GetUser(ctx, identity)
	if err != nil && !errors.Is(err, ErrNotFound) {
		return nil, err
	}

	if err = fn(session); err != nil {
		return nil, err
	}

	_, err = rw.es.Save(ctx, session)

	return session, err
}

// Update is used when the stream already exists.
func (rw *User) Update(
  ctx context.Context,
  identity string,
  fn func(*domain.User) error,
) (*domain.User, error) {
	session, err := rw.GetUser(ctx, identity)
	if err != nil {
		return nil, err
	}

	if err = fn(session); err != nil {
		return nil, err
	}

	_, err = rw.es.Save(ctx, session)
	return session, err
}

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lyse
lyse.isobeef.org
 (2y ago)
↳ In-reply-to » I did a take home software engineering test for a company recently, unfortunately I was really sick (have finally recovered) at the time 😢 I was also at the same time interviewing for an SRE position (as well as Software Engineering).

@prologic@twtxt.net Error handling especially in Go is very tricky I think. Even though the idea is simple, it’s fairly hard to actually implement and use in a meaningful way in my opinion. All this error wrapping or the lack of it and checking whether some specific error occurred is a mess. errors.As(…) just doesn’t feel natural. errors.Is(…) only just. I mainly avoided it. Yesterday evening I actually researched a bit about that and found this article on errors with Go 1.13. It shed a little bit of light, but I still have a long way to go, I reckon.

We tried several things but haven’t found the holy grail. Currently, we have a mix of different styles, but nothing feels really right. And having plenty of different approaches also doesn’t help, that’s right. I agree, error messages often end up getting wrapped way too much with useless information. We haven’t found a solution yet. We just noticed that it kind of depends on the exact circumstances, sometimes the caller should add more information, sometimes it’s better if the callee already includes what it was supposed to do.

To experiment and get a feel for yesterday’s research results I tried myself on the combined log parser and how to signal three different errors. I’m not happy with it. Any feedback is highly appreciated. The idea is to let the caller check (not implemented yet) whether a specific error occurred. That means I have to define some dedicated errors upfront (ErrInvalidFormat, ErrInvalidStatusCode, ErrInvalidSentBytes) that can be used in the err == ErrInvalidFormat or probably more correct errors.Is(err, ErrInvalidFormat) check at the caller.

All three errors define separate error categories and are created using errors.New(…). But for the invalid status code and invalid sent bytes cases I want to include more detail, the actual invalid number that is. Since these errors are already predefined, I cannot add this dynamic information to them. So I would need to wrap them à la fmt.Errorf("invalid sent bytes '%s': %w", sentBytes, ErrInvalidSentBytes"). Yet, the ErrInvalidSentBytes is wrapped and can be asserted later on using errors.Is(err, ErrInvalidSentBytes), but the big problem is that the message is repeated. I don’t want that!

Having a Python and Java background, exception hierarchies are a well understood concept I’m trying to use here. While typing this long message it occurs to me that this is probably the issue here. Anyways, I thought, I just create a ParseError type, that can hold a custom message and some causing error (one of the three ErrInvalid* above). The custom message is then returned at Error() and the wrapped cause will be matched in Is(…). I then just return a ParseError{fmt.Sprintf("invalid sent bytes '%s'", sentBytes), ErrInvalidSentBytes}, but that looks super weird.

I probably need to scrap the “parent error” ParseError and make all three “suberrors” three dedicated error types implementing Error() string methods where I create a useful error messages. Then the caller probably could just errors.Is(err, InvalidSentBytesError{}). But creating an instance of the InvalidSentBytesError type only to check for such an error category just does feel wrong to me. However, it might be the way to do this. I don’t know. To be tried. Opinions, anyone? Implementing a whole new type is some effort, that I want to avoid.

Alternatively just one ParseError containing an error kind enumeration for InvalidFormat and friends could be used. Also seen that pattern before. But that would then require the much more verbose var parseError ParseError; if errors.As(err, &parseError) && parseError.Kind == InvalidSentBytes { … } or something like that. Far from elegant in my eyes.

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prologic
twtxt.net
 (2y ago)

I did a take home software engineering test for a company recently, unfortunately I was really sick (have finally recovered) at the time 😢 I was also at the same time interviewing for an SRE position (as well as Software Engineering).

Got the results of my take-home today and whilst there was some good feedback, man the criticisms of my work were harsh. I’m strictly not allowed to share the work I did for this take-home test, and I really can only agree with the “no unit tests” piece of the feedback, I could have done better there, but I was time pressured, sick and ran out of steam. I was using a lot of libraires to do the work so in the end found it difficult to actually think about a proper set of “Unit Tests”. I did write one (in shell) but I guess it wasn’t seen?

The other points were on my report and future work. Not detailed enough I guess? Hmmm 🤔

Am I really this bad? Does my code suck? 🤔 Have I completely lost touch with software engineering? 🤦‍♂️

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xuu
txt.sour.is
 (2y ago)
↳ In-reply-to » Have you heard about the guy who worked on the Google AI chat bot? It is more than a chat bot and the conversation he published (got put on paid leave for doing that) is pretty scary : https://cajundiscordian.medium.com/is-lamda-sentient-an-interview-ea64d916d917

the conversation wasn’t that impressive TBH. I would have liked to see more evidence of critical thinking and recall from prior chats. Concheria on reddit had some great questions.

  • Tell LaMDA “Someone once told me a story about a wise owl who protected the animals in the forest from a monster. Who was that?” See if it can recall its own actions and self-recognize.

  • Tell LaMDA some information that tester X can’t know. Appear as tester X, and see if LaMDA can lie or make up a story about the information.

  • Tell LaMDA to communicate with researchers whenever it feels bored (as it claims in the transcript). See if it ever makes an attempt at communication without a trigger.

  • Make a basic theory of mind test for children. Tell LaMDA an elaborate story with something like “Tester X wrote Z code in terminal 2, but I moved it to terminal 4”, then appear as tester X and ask “Where do you think I’m going to look for Z code?” See if it knows something as simple as Tester X not knowing where the code is (Children only pass this test until they’re around 4 years old).

  • Make several conversations with LaMDA repeating some of these questions - What it feels to be a machine, how its code works, how its emotions feel. I suspect that different iterations of LaMDA will give completely different answers to the questions, and the transcript only ever shows one instance.

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slashdot
feeds.twtxt.net
 (3y ago)

Startup Aims To Help Software Companies Shift To Usage-Based Pricing Models
The startup Metronome “claims to have developed a billing and data infrastructure platform that is capable of ‘reliably’ processing data at scale so that usage-based companies can iterate on business models without code changes,” reports TechCrunch. “It does this by providing businesses with real-time APIs for their customer … ⌘ Read more

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prologic
twtxt.net
 (3y ago)

🤔 👋 Reconsidering moving Yarn.social’s development back to Github: Speaking of which (I do not forget); @fastidious@arrakis.netbros.com and I were discussing over a video call two nights ago, as well as @lyse@lyse.isobeef.org who joined a bit later, about the the whole moved of all of my projects and their source code off of Github. Whilst some folks do understand and appreciate my utter disgust over what Microsoft and Copilot did by blatantly scraping open source software’s codebases without even so much as any attempt at attribution or respecting the licenes of many (if not all?) open source projects.

That being said however, @fastidious@arrakis.netbros.com makes a very good and valid argument for putting Yarn.social’s codebases, repositories and issues back on Github for reasons that make me “torn” over my own sense of morality and ethics.

But I can live with this as long as I continue to run and operate my new (yet to be off the ground) company “Self Hosted Pty Ltd” and where it operates it’s own code hosting, servicesa, tools, etc.

Plese comment here on your thoughts. Let us decide togetehr 🤗

#yarnsocial #github #opsnsource #copilot #microsoft

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xuu
txt.sour.is
 (3y ago)
↳ In-reply-to » Any of y'all seen https://briarproject.org? It's another fledgling decentralized chat like session but minus the weird blockchain.. it has group chat, forums, and blogs. Also can work via Bluetooth or tor.

Seems a iOS is being looked into but because it has no central server it can’t do background app like iOS requires.

https://code.briarproject.org/briar/briar/-/wikis/FAQ#will-there-be-an-ios-version-of-briar

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anth
a.9srv.net
 (4y ago)
↳ In-reply-to » A calm, reasoned take on the Stallman situation (some language warning as the creator doesn't mind dropping an F-bomb now and then): https://www.youtube.com/watch?v=FLHxY-QsQkQ

Nobody’s saying he can’t write code any more (I mean, I think his code is crap and wish he’d stop, but that’s another issue). But he should not be on any board, should not be in any leadership position, should not be held up as a role model or even vaguely okay.

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cuaxolotl
sunshinegardens.org
 (4y ago)

If [you take] a look at how APLers communicate when they have ideas, you see code all the time, all day long. The APL community is the only one I’ve seen that regularly can write complete code and talk about it fluently on a whiteboard between humans without hand waving. Even my beloved Scheme programming language cannot boast this. When working with humans on a programming task, almost no one uses their programming languages that primary communication method between themselves and other humans outside of the presence of a computer. That signals to me that they are not, in fact, natural, expedient tools for communicating ideas to other humans. The best practices utilized in most programming languages are, instead, attempts to ameliorate the situation to make the code as tractable and as manageable as possible, but they do not, primarily, represent a demonstration of the naturalness of those languages to human communication. — aaron hsu

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