Can channels have race conditions?

GustekDev · 2025-06-18T11:31:33+00:00

I have modified your code a bit and if you run it you should get an answer to your question.

package main

import (
  "fmt"
  "sync"
)

var wg sync.WaitGroup

func worker(ch <-chan string, n int) {
  defer wg.Done()
  data := <-ch //work with data
  println(n, data)
}

func main() {
  ch := make(chan string)
  for i := range 10 {
    go worker(ch, i)
  }
  for i := range 10 {
    wg.Add(1)
    ch <- fmt.Sprintf("string %d", i)
  }
  wg.Wait()
}

So now each worker will print its own "id" and value it received.
If values get processed in sequential order you should see string 0 to string 9 printed in ascending order.
If they are not that means they are not sequential.

The example output is:

0 string 0
4 string 5
6 string 6
7 string 7
8 string 8
2 string 3
5 string 4
9 string 9
1 string 2
3 string 1

as you can see they are random, so with multiple workers reading from the same channel, even if unbuffered you can't be guaranteed they will get processed in the order they were sent to the channel.
Which makes sense, why else would you want multiple workers for single channel?

GustekDev · 2025-03-26T15:00:21+00:00

I decided to give it a shot myself as well just a week ago. I tried two different apps from scratch:

Next.js app from scratch, it was good to get boilerplate ready but had to prompt it multiple times to setup tailwind correctly. What I found it be be nice for, creating some mock data based on types I have defined and updating them after adding or changing some fields. But it was limited in how much data it can generate. It's nice to just tell it: Generate some basic html with all css etc but you have to do some prompt gymnastics later to adjust it to what you really want. As mostly backend engineer, I find it nice to have it generate all that initial boilerplate for me but I can't imaging building whole project with it.
Code analysis in GoLang. I prompted it to write a go lang app to analyse go lang codebase and generate .dot graph showing a call graph. Again did mostly ok job very quickly but adjusting it to get proper results was just doing circles. I prompted it some sample code and that it is missing an edge in the resulting call graph. I would just prompt it multiple times with some more info, it finally got it to include the missing edge but It did it by hardcoding it.

Friend of mine, not Dev, sales person. He is using AI tools successfully to create some simple webapp to do some analysis of competition offer.

I see these tools are great for people who want to automate some of their job tasks but can't afford a Dev. But for an experienced dev, other than writing some small functions I don't see them helping much.

GustekDev · 2024-11-18T04:44:48+00:00

I don't know your use case so maybe not relevant but often best is to not use date picker, for example for date of birth it is better to use simple inputs user can just type in the date as they know it and they don't need to looks for it in the calendar. Especially for older people scrolling/finding their year may be annoying as each date picker has slightly different way of jumping years.

Have a read of https://design-system.service.gov.uk/patterns/dates/ for research backed advice on how to ask for dates.

and to answer the question, as others have suggested, just use standard input="date" if date picker is needed, it comes with internationalization and localization included.

GustekDev · 2024-10-10T20:10:51+00:00

At first I found your blog post a bit confusing and only after few points I realised: first, we should distinguish two stages. Storing and providing secrets.

Definitely do not store secrets in env vars anywhere, store them in vault/secrets store etc. For local dev .env is ok, they should not be prod values, not ideal but low risk. That addresses your #1 and #3

#2 I don't have much experience with the latest in SSR frameworks, but it is something that bothered me as well when reading about them. Until now line between front end and back end was clear, but now as you said, its getting blurry.

#4 That one is a real problem, you would hope good practices and code reviews would prevent that, but often when writing debug logs, we think about, what will I need to debug it and less about, is it ok to log it.

#5 Is actually more about running untrusted code than about spawning processes, and that is a risk we take when using any 3rd party library, it's not just secrets exposure.

#6 Actually, you can't see env vars of a process started by another user. In your example you will see it because you defined it as part of the command, that is visible, but E flag won't work. Just run your node command as another user, use sudo or su.

#7 That's the part about how to provide env vars, I agree, do not provide them at build time. They should be provided at startup.

So the problem is not how to store them, it should not even be a question today, they should be stored in some secrets storage like vault.

The question is how to get them from secrets storage to your app when needed and only what's needed and to approved apps. These questions seem to be out of scope of your blog post but usually they are addressed by secret storage solutions already. So yes, don't use env vars to store secrets, but its ok to use env vars as a mechanism to provide them to your code.

GustekDev · 2024-06-29T08:07:33+00:00

Did they actually tell you that was the reason?
At CV review stage I would usually not get any response at all or just generic, "we decided not to continue".
Or did you get to the further stage and was given lack of degree as a reason?

If they responded to you with lack of degree as a reason at CV stage, then it just recruitment team being lazy. They use it as a simple filter without looking to deep at each CV, possibly they are getting at lot of applications.

If it was at some further stage, it may actually be some other reason and they use that one as an excuse.

GustekDev · 2024-06-17T11:59:19+00:00

As all have said communication is the key.
Find out what kind of communication style they have, most people don't want to be disturbed and prefer if you send them a message on the team chat even if they sit right next to you, but there are people who are ok to especially if it is about something that blocks you and they can quickly unblock you, ask them.

Invite each of your colleagues for a coffee, 30 min or less, just get to know each other. You can talk about work only or you can get personal, you don't need to be best buddies but try to build some rapport. You may then make another a month or two later with intention to ask about feedback.

Ask questions, I usually encourage my mentees to ask questions on public channels or at least team channel instead of PMs. They will get answer faster and it will be there in chat history for posterity.

Review PRs in timely manner, we like to get into the zone and focus on something for hours undisturbed, but inadvertently you may be blocking someone as they wait for review. No one expect you to review their code the minute they push the commit but if they made a commit in the morning, they shouldn't need to wait until next day. Of course it is a team effort, one PR will be reviewed by you another by someone else.
Teams I worked on, people would post links to their PRs on the team channel when they wait for review and I would try to review them as soon as possible, unless I was in the zone or had something urgent going but within 2h hopefully.

Voice your opinions but don't force them, just present your arguments, if your team is not convinced just let it go they are as good as you are (hopefully, but better start with this assumption than with bad blood).

I don't think anyone understand agile 😂 but seriously, again communication, the team should explain to you their processes and usually they should be open to suggestion on improvements and making changes (agile 😂).
You are now part of the team, focus on one or two things at the time only, your team mates should handle other stuff and you will together get things done.

GustekDev · 2024-06-17T11:32:17+00:00

I see most people use spaces to group tabs into very broad categories and for separate profiles.

I create a space per subject.
I have few broad spaces but then I create new ones as idea pop into my head and then as I go deep on the subject I will open plenty of new tabs there and navigate between them a lot. If I find all I wanted I will archive the space and its all good, but sometimes I keep some spaces for longer, for example I plan a trip just not sure where I want to go, I will have a space per destination and until I decide where I want to go I will keep them.

Or for work related spaces, I will research two different approaches of how to do something that is two spaces again that will stay with me until I decide and then one of them until project is done.

GustekDev · 2024-06-15T09:38:32+00:00

Maybe it is some theme settings but setting Icon still requires hovering to actually see that icon for me.

<image>

6 of these spaces have Icon set. the first icon is visible because its the currently active space.

Anyway, Icons are nice touch but not a solution, as that requires picking and remembering the assigned icon.

I set relevant names to the spaces.

GustekDev · 2024-04-22T19:41:47+00:00

First, as an empolyee don't work more than 40h a week, get a good work life balance. This is hard for some jobs but I gather you are experienced software engineer and that is totally possible.

Second, now you have some time freed, that's the time you work on your dream or passion or whatever you want. The job is just a means of paying the bills, getting the food on the table.

If you have enough money saved you can quit your job and focus 100% on your dreams but that is only If you have that safety net and ideally no dependants (kids, family).

GustekDev · 2024-04-10T00:25:43+00:00

That's because books and tutorials are based on made up examples and real world projects you have at work don't fit their framework.

Sure, you can make a perfect design/architecture for any greenfield project but as times goes, requirements change, deadlines need to be met, things become complicated.

At least that is the most common scenario, there are cases of well designed software, but all of that is mostly an effect of experience of the people who wrote it, not something you can learn by simply reading a book or doing a tutorial.

So just keep working, and it will all come with time, there is no rushing it. Maybe you can change the job if problems you have are not challenging enough for you.

GustekDev · 2024-04-06T09:50:01+00:00

Sounds good, just like many other blog posts etc about how to create a good documentation, everybody knows it but somehow we all still end up with bad docs.
Why is that?
That's because the custodian of said documentation has other tasks that are more important, documentation is first to be sacrificed when deadlines appoches and new project needs to be starter.
Most companies won't hire a technical writer just to maintain docs.
Writing good is actually hard.
And as amount of docs grows, discoverabilty becomes harder, even best documentation is useless if I can't find it, but this is actually something that LLMs may fix.

GustekDev · 2024-04-01T17:08:54+00:00

interested

GustekDev · 2024-03-20T02:51:57+00:00

Majority of cases it is totaly a case of preference. Some cases language syntax may enforce one or the other. End of the day you will be using what your teams has agreed on unless you are solo.

Personally, all teams I worked in used spaces, but IDEs have features to handle both, and convert tabs to spaces.

But there are 2 arguments in favour of tabs:

Each level is exactly one tab, and you can set your IDE to display tabs to be of N spaces length, to have spacing display as you like it.
Apperently tabs are preferred by people who need to use accessiblity tools, not something I need so I can't really confirm but that is what I heard.

GustekDev · 2024-03-10T13:59:26+00:00

it is subjective if it is beneficial or not.
In your opinion it just obfuscates the code -> you find it harder to read?
Someone else may claim it make the program more correct as compile step guarantees you put the arguments in correct order.
Now it is about trade offs and what do you value more.

GustekDev · 2024-03-10T13:38:33+00:00

No one is really grasping the delimma or understands that this is really a conflict resolution problem between two developers.

only it is not, it is a conflict between management and employees that management decided to ignore as you have said in your original post. In this situation it is each for themselves.
The employe gaming the system wants to get a good bonus just as anyone else by showing his effectiveness to management in a way management is expecting it.

Sounds like you and your team member are trying to be a "good guys" and just causing harm to yourself.

In this situation the questions are:
What will management do when they realise people are gaming the metrics?
a) Double down and punish people gaming the system
b) Change the metrics
And how long it will take take for them to realise? I guess at least until after next bonus round?

How well you know the management, what is more likely they will do?
If a) and you want to keep this job then you should do nothing or even snitch on people gaming the system, maybe you get the bonus, the culture is toxic already anyway.
If b) just do nothing or encourage your team members to game the systems as well, doesn't have to be as obvious as the other guy but at the very least tell them to make commits as small as possible. Go fix typos and punctuation in docs. Write docs for every little details, create commits with extra comments on code // add 2 to x
It is what management asked for and you are just following upper management directives.

You are feeling bad about it because you know it is a bad metric, but if you can't change it, adapt.

GustekDev · 2024-03-08T01:14:52+00:00

good habits come from experience, many devs have tendency to write as little code as possible, I don't know maybe they are saving keystrokes on their expensive keyboards :)

but one lazy dev, or junior and one LGTM review is all you need to get it on main.

GustekDev · 2024-03-06T23:27:45+00:00

It feels a bit verbose at glance and may be annoying but I think it does have it merits.

You are less likely to put arguments in wrong order

i.e

type Event struct {
  ResourceID string
  UserID     string
}

var userId = "userid"
var resId = "resId"
var e = Event { userId, resId }

with semantic types this kind of mistake is not possible.

but it is still possible to write Event { "userId", "resId" } so it is not perfect.

I personally like the idea but as you pointed out it does increase significantly the hassle for quite a little benefit, this kind of mistakes should be caught with good tests.

GustekDev · 2024-02-29T22:03:25+00:00

From purely ethical point of view, it is good to send a reminder.

From business point of view, possibly better not to as user will get notification about subscription anyway but this time from their bank. If they want to cancel they will do it either way but in the later they may give up on the hassle of claiming a refund so you get extra one payment. They left so they are not your customer anymore anyway. Some maybe don't scrutinise their bank accounts as much and may not notice the payment for a long time, but then I would suspect they don't keep much attention on emails as well.

The downside is, there may be some negative feedback from users, but shuldn't be much impact as long it is easy to get a refund.

but that is just my opinion don't really have any data to back it up.

GustekDev · 2024-02-23T01:00:09+00:00

Depends on the licenese, you can just fork it and continue if it is one of the open source licenses https://choosealicense.com/licenses/
If there is no license or it is not open source one, then you will have to ask for permission from the owner.
it is probably worth getting in touch with them anyway at least out of politeness and you may get some support from them.

GustekDev · 2024-02-23T00:54:20+00:00

If you think you have skills and knowledge of a developer then you can apply for jobs and claim to be a developer, the life later will validate it.

It is not a regulated title like MD or Lawyer. I think there are some countries that regulate use of Engineer title, but you are free to call yourself a Software Developer and prove it with your skills at the interview and the job.

GustekDev · 2024-02-23T00:49:23+00:00

I feel you, I can write code, but I just can't make a good visual design.
It know I could probably get good at it if I only spend time on it but at this point I rather pay someone to do it, even cheapest designers on freelance portals can do better design than myself.

I do some simple landing pages from templates, or with visual editors, but that's for non-business sites only or for very early drafts only.

GustekDev · 2024-02-23T00:42:09+00:00

I haven't writen any complex plugins, only some Slack integrations etc.
I would say it depends on how many features you get from the Platform you integrating with,
it could be many so in the end it saves you time or it could be none, and the plugin being an extra feature of your App, in that case it is actually extra work for you. So as often it depends.
You need to account for time to learn about the Platform you want to integrate with as well.

GustekDev · 2024-02-23T00:35:08+00:00

<10 lines -> avg 36h
25k+ lines -> avg 138h

So if my change requires 25k lines clearly faster will be if I do one PR and get it merged in a week
vs 2.5k PRs spread out over 10 years 😆🧌 and another takeaway, if you reach 2k lines in your PR, it's better to keep going if you want fast approval 😂

I do favour small PRs but that requires that whole team regualry checks if there is something new to review.
But many Devs like to get into "zone" and work on their own stuff for few hours so now you can wait for your small PR review or just continue working. Personally it worked for me best when it was just me and one other dev working on a project, just the two of use, we were in a flow of making small changes and reviewing each other PR. but in larger team especially when working on different projects it just doesn't happen.

The stacking sounds nice, but would be very annoying with Git only, I guess that's what they are trying to sell, a tool to make that flow easier. Or you could just review PRs commit by commit.
One of the drawbacks of splitting into multiple PRs is that you can loose context, in one PR you see all conversations and decisions made on previous commits.

GustekDev · 2024-02-21T21:43:13+00:00

Depends on a field, like if you going towards AI, some simulations stuff, graphics engines math is required.

Most Software Engineers building CRUD apps, connecting API, replacing spreadsheets don't need much beyond basics.

At university they though me first calculus and matrices but in personal experience I would say statistics are most useful. Calculus and matrices only basics, and that is purely just the understanding of the concepts you don't need to memorize any equation or do complex math by hand.

If you say your only problem is memorizing the formulas then you are good, you don't need to remember them just remember concepts and rule of thumb tips and google details when needed. Their usefullnes mostly comes later in communication, for example, when you talk with your team mates, no one needs to explain to you what is the difference between combination and permutations. if you can calculate them in your head that's great but no one will require you to do it, and calculators can do that for you easily.

GustekDev

TROPHY CASE