sandeepk

So I was fixing some slow tests, and whenever I ran them through the pytest command, I was greeted with the dreaded max_locks_per_transaction error.

My first instinct? Just crank up the max_locks_per_transaction from 64 to 1024.

But... that didn’t feel right. I recreate my DB frequently, which means I’d have to set that value again and again. It felt like a hacky workaround rather than a proper solution.

Then, like any developer, I started digging around — first checking the Confluence page for dev docs to see if anyone else had faced this issue. No luck. Then I moved to Slack, and that’s where I found this command someone had shared:

pytest -n=0

This was new to me. So, like any sane dev in 2025, I asked ChatGPT what this was about. That’s how I came across pytest-xdist.

What is pytest-xdist?

The pytest-xdist plugin extends pytest with new test execution modes — the most common one is distributing tests across multiple CPUs to speed up test execution.

What does pytest-xdist do?

Runs tests in parallel using <numprocesses> workers (Python processes), which is a game changer when: – You have a large test suite
– Each test takes a significant amount of time
– Your tests are independent (i.e., no shared global state)

That’s pretty much it — I plugged in pytest -n=0 and boom, no more transaction locks errors.

Cheers!

References – https://pytest-xdist.readthedocs.io/en/stable/ – https://docs.pytest.org/en/stable/reference/reference.html

#pytest #Python #chatgpt #debugging

I’ve been working on a few side projects and using ChatGPT for ideation and brainstorming around ideas and features for the MVP. As part of this, I needed a logo for my app. Naturally, I turned to AI to help me generate one.

However, I noticed that when generating images, ChatGPT doesn’t always follow the guidelines perfectly. Each time I asked for a new version, it would create a completely different image, which made it difficult to iterate or make small tweaks.

But I found a better way.

Instead of generating a brand new image every time, I first explained my app idea and the name. ChatGPT generated an image I liked.

So I asked ChatGPT to generate the JSON for the image instead. I then manually tweaked the JSON file to adjust things exactly the way I wanted. When I asked ChatGPT to generate the image based on the updated JSON, it finally created the image as per my request — no random changes, just the specific adjustments I needed.

Exploration Phase

SplitX logo

{
  "image": {
    "file_name": "splitX_icon_with_text.png",
    "background_color": "black",
    "elements": [
      {
        "type": "text",
        "content": "SplitX",
        "font_style": "bold",
        "font_color": "white",
        "position": "center",
        "font_size": "large"
      },
      {
        "type": "shape",
        "shape_type": "X",
        "style": "geometric split",
        "colors": [
          {
            "section": "top-left",
            "gradient": ["#FF4E50", "#F9D423"]
          },
          {
            "section": "bottom-left",
            "gradient": ["#F9D423", "#FC913A"]
          },
          {
            "section": "top-right",
            "gradient": ["#24C6DC", "#514A9D"]
          },
          {
            "section": "bottom-right",
            "gradient": ["#514A9D", "#E55D87"]
          }
        ],
        "position": "center behind text",
        "style_notes": "Each quadrant of the X has a distinct gradient, giving a modern and vibrant look. The X is split visually in the middle, aligning with the 'Split' theme."
      }
    ]
  }
}

Final Design

SplitX logo Updated JSON

{
  "image": {
    "file_name": "splitX_icon_with_text.png",
    "background_color": "transparent",
    "elements": [
      {
        "type": "shape",
        "shape_type": "X",
        "style": "geometric split",
        "colors": [
          {
            "section": "top-left",
            "gradient": [
              "#FF4E50",
              "#F9D423"
            ]
          },
          {
            "section": "bottom-left",
            "gradient": [
              "#F9D423",
              "#FC913A"
            ]
          },
          {
            "section": "top-right",
            "gradient": [
              "#24C6DC",
              "#514A9D"
            ]
          },
          {
            "section": "bottom-right",
            "gradient": [
              "#514A9D",
              "#E55D87"
            ]
          }
        ],
        "position": "center ",
        "style_notes": "Each quadrant of the X has a distinct gradient, giving a modern and vibrant look. The X is split visually in the middle, aligning with the 'Split' theme."
      }
    ]
  }
}

If you want to tweak or refine an image, first generate the JSON, make your changes there, and then ask ChatGPT to generate the image using your updated JSON. This gives you much more control over the final result.

Cheers!

P.S. Feel free to check out the app — it's live now at https://splitx.org/. Would love to hear what you think!

1. Why did you make the blog in the first place?

This blog initially started as part of the summer training by DGPLUG, where the good folks emphasize the importance of blogging and encourage everyone to write—about anything! That motivation got me into the habit, and I’ve been blogging on and off ever since.

2. What platform are you using to manage your blog and why did you choose it?

I primarily write on WriteFreely, hosted by Kushal, who was kind enough to host an instance. I also occasionally write on my WordPress blog. So yeah, I have two blogs.

3. Have you blogged on other platforms before?

I started with WordPress because it was a simple and fast way to get started. Even now, I sometimes post there, but most of my recent posts have moved to the WriteFreely instance.

4. How do you write your posts?

I usually just sit down and write everything in one go. Followed by editing part—skimming through it once, making quick changes, and then hitting publish.

5. When do you feel most inspired to write?

Honestly, I don’t wait for inspiration. I write whenever I feel like it—sometimes in a diary, sometimes on my laptop. A few of those thoughts end up as blog posts, while the rest get lost in random notes and files.

6. Do you publish immediately after writing or do you let it simmer a bit as a draft?

It depends. After reading a few books and articles on writing, I started following a simple process: finish a draft in one sitting, come back to it later for editing, and then publish.

7. Your favorite post on your blog?

Ahh! This blog post on Google Cloud IAM is one I really like because people told me it was well-written! :)

8. Any future plans for your blog? Maybe a redesign, changing the tag system, etc.?

Nope! I like it as it is. Keeping it simple for now.

A big thanks to Jason for mentioning me in the challenge!

Cheers!

In CSS, combinators are used to select content by combining selectors in specific relationships. There are different types of relationships that can be used to combine selectors.

Descendant combinator

The descendant combinator is represented by a space “ ” and typically used between two selectors. It selects the second selector if the first selector is the ancestor (parent, parent parent's) element. These selectors are called the descendant selectors.

.cover p {
    color: red;
}

<div class="cover"><p>Text in .cover</p></div>
<p>Text not in .cover</p>

In this example, the text “Text in .cover” will be displayed in red.

Child combinators

The child combinator is represented by “>” and is used between two selectors. In this, an element is only selected if the second selector is the direct child of the first selector element. This means there should not be any other selector between the first selector element and second element selector.

ul > li {
    border-top: 5px solid red;
} 

<ul>
    <li>Unordered item</li>
    <li>Unordered item
        <ol>
            <li>Item 1</li>
            <li>Item 2</li>
        </ol>
    </li>
</ul>

In this example, the <li> element with the text “Unordered item” will have a red top border.

Adjacent sibling combinator

The adjacent sibling combinator is represented by “+” is placed between the two CSS selector. In this element is selected if the selector element is directly followed by the first element selector or only the adjacent sibling

h1 + span {
    font-weight: bold;
    background-color: #333;
    color: #fff;
    padding: .5em;
}

<div>
    <h1>A heading</h1>
    <span>Veggies es bonus vobis, proinde vos postulo essum magis kohlrabi welsh onion daikon amaranth tatsoi tomatillo
            melon azuki bean garlic.</span>

    <span>Gumbo beet greens corn soko endive gumbo gourd. Parsley shallot courgette tatsoi pea sprouts fava bean collard
            greens dandelion okra wakame tomato. Dandelion cucumber earthnut pea peanut soko zucchini.</span>
</div>

In this example, the first element will have the given CSS properties.

General sibling combinator

The general sibling combinator is represented by “~“. It selects all the sibling element, not only the direct sibling element, then we use the general sibling combinator.

h1 ~ h2 {
    font-weight: bold;
    background-color: #333;
    color: #fff;
    padding: .5em;
}

<article>
    <h1>A heading</h1>
    <h2>I am a paragraph.</h2>
    <div>I am a div</div>
    <h2>I am another paragraph.</h2>
</article>

In this example, every <h2> element will have the given CSS properties.

CSS combinators provide powerful ways to select and style content based on their relationships in the HTML structure. By understanding combinators, we can create clean, maintainable, and responsive web designs.

Cheers!

References – MDN Web Docs

#CSS #Combinators #WebDevelopment #FrontendDev

Today, I decided to analyze my bank account statement by downloading it from the day I opened my bank account. To my surprise, it was presented as a web page. Initially, my inner developer urged me to write code to scrape that data. However, feeling a bit lazy, I postponed doing so.

Later in the evening, I searched the web to find an alternate way to extract the data and discovered that HTML tables can be converted to CSV files. All I had to do was save the code in CSV format. I opened the Chrome browser's inspect code feature, copied the table, saved it with the CSV extension, and then opened the file with LibreOffice. Voila! I had the spreadsheet with all my transactions.

Cheers!

#TIL #CSV #HTML Table

The Debug Diary – Chapter I

Lately, I was debugging an issue with the importer tasks of our codebase and came across a code block which looks fine but makes an extra database query in the loop. When you have a look at the Django ORM query

jato_vehicles = JatoVehicle.objects.filter(
    year__in=available_years,<more_filters>
).only("manufacturer_code", "uid", "year", "model", "trim")

for entry in jato_vehicles.iterator():
    if entry.manufacturer_code:
        <logic>
    ymt_key = (entry.year, entry.model, entry.trim_processed)
...

you will notice we are using only, which only loads the set of fields mentioned and deferred other fields, but in the loop, we are using the field trim_processed which is a deferred field and will result in an extra database call.

Now, as we have identified the performance issue, the best way to handle the cases like this is to use values or values_list. The use of only should be discouraged in the cases like these.

Update code will look like this

jato_vehicles = JatoVehicle.objects.filter(
    year__in=available_years,<more-filters>).values_list(
    "manufacturer_code",
    "uid",
    "year",
    "model",
    "trim_processed",
    named=True,
)

for entry in jato_vehicles.iterator():
    if entry.manufacturer_code:
        <logic>
    ymt_key = (entry.year, entry.model, entry.trim_processed)
...

By doing this, we are safe from accessing the fields which are not mentioned in the values_list. If anyone tries to do so, an exception will be raised.

** By using named=True we get the result as a named tuple which makes it easy to access the values :)

Cheers!

#Django #ORM #Debug

select_for_update is the answer if you want to acquire a lock on the row. The lock is only released after the transaction is completed. This is similar to the Select for update statement in the SQL query.

>>> Dealership.objects.select_for_update().get(pk='iamid')
>>> # Here lock is only required on Dealership object
>>> Dealership.objects.select_related('oem').select_for_update(of=('self',))

select_for_update have these four arguments with these default value – nowait=False – skiplocked=False – of=() – nokey=False

Let's see what these all arguments mean

nowait

Think of the scenario where the lock is already acquired by another query, in this case, you want your query to wait or raise an error, This behavior can be controlled by nowait, If nowait=True we will raise the DatabaseError otherwise it will wait for the lock to be released.

skip_locked

As somewhat name implies, it helps to decide whether to consider a locked row in the evaluated query. If the skip_locked=true locked rows will not be considered.

nowait and skip_locked are mutually exclusive using both together will raise ValueError

of

In select_for_update when the query is evaluated, the lock is also acquired on the select related rows as in the query. If one doesn't wish the same, they can use of where they can specify fields to acquire a lock on

>>> Dealership.objects.select_related('oem').select_for_update(of=('self',))
# Just be sure we don't have any nullable relation with OEM

no_key

This helps you to create a weak lock. This means the other query can create new rows which refer to the locked rows (any reference relationship).

Few more important points to keep in mind select_for_update doesn't allow nullable relations, you have to explicitly exclude these nullable conditions. In auto-commit mode, select_for_update fails with error TransactionManagementError you have to add code in a transaction explicitly. I have struggled around these points :).

Here is all about select_for_update which you require to know to use in your code and to do changes to your database.

Cheers!

#Python #Django #ORM #Database

Today, we are going to see how we can use | operator in our python code to achieve clean code.

Here is the code where we have used map and filter for a specific operation.

In [1]: arr = [11, 12, 14, 15, 18]
In [2]: list(map(lambda x: x * 2, filter(lambda x: x%2 ==1, arr)))
Out[2]: [22, 30]

The same code with Pipes.

In [1]: from pipe import select, where
In [2]: arr = [11, 12, 14, 15, 18]
In [3]: list(arr | where (lambda x: x%2 ==1) | select(lambda x:x *2))
Out[3]: [22, 30]

Pipes passes the result of one function to another function, have inbuilt pipes method like select, where, tee, traverse.

Install Pipe

>> pip install pipe

traverse

Recursively unfold iterable:

In [12]: arr = [[1,2,3], [3,4,[56]]]
In [13]: list(arr | traverse)
Out[13]: [1, 2, 3, 3, 4, 56]

select()

An alias for map().

In [1]: arr = [11, 12, 14, 15, 18]
In [2]: list(filter(lambda x: x%2 ==1, arr))
Out[2]: [11, 15]

where()

Only yields the matching items of the given iterable:

In [1]: arr = [11, 12, 14, 15, 18]
In [2]: list(arr | where(lambda x: x % 2 == 0))
Out[2]: [12, 14, 18]

sort()

Like Python's built-in “sorted” primitive. Allows cmp (Python 2.x only), key, and reverse arguments. By default, sorts using the identity function as the key.

In [1]:  ''.join("python" | sort)
Out[1]:  'hnopty'

reverse

Like Python's built-in “reversed” primitive.

In [1]:  list([1, 2, 3] | reverse)
Out[1]:   [3, 2, 1]

strip

Like Python's strip-method for str.

In [1]:  '  abc   ' | strip
Out[1]:  'abc'

That's all for today, In this blog you have seen how to install the Pipe and use the Pipe to write clean and short code using inbuilt pipes, you can check more over here

Cheers!

#100DaysToOffload #Python #DGPLUG

My work required me to profile one of our Django applications, to help identify the point in the application which we can improve to reach our North Star. So, I thought it will be great to share my learning and tools, that I have used to get the job done.

What is Profiling?

Profiling is a measure of the time or memory consumption of the running program. This data further can be used for program optimization.

They are many tools/libraries out there which can be used to do the job. I have found these helpful.

Apache JMeter

It is open-source software, which is great to load and performance test web applications. It's easy to set up and can be configured for what we want in the result report.

Pyinstrument

Pyinstrument is a Python profiler that offers a Django middleware to record the profiling. The profiler generates profile data for every request. The PYINSTRUMENTPROFILEDIR contains a directory that stores the profile data, which is in HTML format. You can check how it works over here

Django Query Count

Django Query Count is a middleware that prints the number of database queries made during the request processing. There are two possible settings for this, which can be found here

Django Silk

Django Silk is middleware for intercepting Requests/Responses. We can profile a block of code or functions, either manually or dynamically. It also has a user interface for inspection and visualization

So, here are some of the tools which can be of great help in profiling your code and putting your effort in the right direction of optimization applications.

Cheers!

#100DaysToOffload #Python #DGPLUG

Nowadays, every project has a docker image, to ease out the local setup and deployment process. We can attach these running container to our editor and can do changes on the go. We will be talking about the VS Code editor and how to use it to attach to the running container.

First thing first, run your container image and open up the VS Code editor, you will require to install following plugin

  1. Remote-Container
  2. Remote Development

Now, after installing these plugins, follow the steps below.

  • Press the F1 key to open Command Palette and choose Remote-Containers: Attach to Running Container... VS Code Palette
  • Choose your running container from the list, and voilà.
  • After this step, a new VS Code editor will open, which will be connected to your code. VS Code bar
  • You need to re-install plugin for this again form marketplace.

After this, you are all set to playground the code.

Cheers!

#100DaysToOffload #VSCode #Containers #Docker