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Category: Misc Languages

Azure Functions and (Lack of) F# Support

Published 2021-08-04 by Kevin Feasel

Jamie Dixon has a shaggy dog tale:

When Azure Functions first came out, F# had pretty good support – templates, the ability to run a .fsx file, cool examples written by Don… Fast forward to 2021 and we have bupkis. I recently wrote a dictionary of amino acid weights that would be perfect as a service: pass in a kmer length and weight, get all hits from amino acids.

I first attempted to create a function app, select a .fsx template, and write the code in my browser. Alas, only .csx scripting is available.

Not to be too cutesy about it, but it would be nice if the product which allows for the execution of functions in a cloud service would support the .NET language which most explicitly embraces the notion of functions. If you feel similarly, there is an open feedback ticket.

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An Introduction to ML.NET

Published 2021-07-30 by Kevin Feasel

Ivan Matec gives us a walkthrough of the ML.NET library and its Model Builder component:

Before we dive into our example, let’s talk a bit about ML.NET history and its current state.

ML.NET draws its origins from the 2002’s Microsoft Research project named TMSN, which stands for “test mining search and navigation.” Later it was renamed to TLC, “the learning code.” ML.NET war derived from the TLC library. Initially, it was used on internal Microsoft products.

The first publicly available version ML.NET 1.0 was released in 2019. It included the Model Builder add-in and AutoML (Automated Machine Learning) capabilities.

The current version is 1.6.0. More details about all releases can be found on the official ML.NET release page.

ML.NET is not a bad library if you need to do some fairly simple work

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Working with App Secrets in .NET Core

Published 2021-07-30 by Kevin Feasel

Santosh Hari shows us how to use application secrets when building .NET Core applications:

I was writing a sample dotnetcore console application for a talk because why I felt using a sample aspnet core web app was overkill. The app was connecting to a bunch of Azure cloud and 3rd party services (think Twilio API for SMS or LaunchDarkly API for Feature Flags) and I had to deal with connection strings.

Now I have a nasty habit of “accidentally” checking in connection string and secrets into public GitHub repositories, so I wanted to do this right from the get go.

That’s a bad habit to be in, and Santosh shows us how we can avoid doing that via use of application secrets.

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Visualizing Data over Time with F#

Published 2021-07-30 by Kevin Feasel

Codesuji takes us through creating an interesting video:

How is this accomplished? I reach into F#’s bag of tricks to leverage Deedle, Plotly.NET, and ffmpeg in order to transform a series of data files into a singular video showing county-level drought data from 1900-2016. Together these bring static data into a dynamic representation. For reference, the Palmer Drought Severity Index (PDSI) typically ranges from -10 (dry) to 10 (wet). Putting this all together is pretty straight-forward, but I wanted to call out a couple specific parts. For this particular example Deedle is overkill, but pairing it with Plotly.NET can often be useful in more complex situations. Plotly offers some nice customization options, which I take advantage of below. Once all the images are generated with Plotly, F# can shell out to ffmpeg to perform the video assembly. I do this in two parts, creating both an mp4 and webm file.

We’re reading datasets, parsing text files, deserializing JSON contents, building a visual for each point in time, and then creating a video out of it—all in 100 lines of code. Not bad.

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Contrasting Scala and Python wrt Spark

Published 2021-07-20 by Kevin Feasel

Sanjay Rathore contrasts two of the three key Apache Spark languages:

Imagine the first day of a new Apache Spark project. The project manager looks at the team and says: which one to choose, scala or python. So let’s start with “scala vs python for spark”. 

You may wonder if this is a tricky question. What does the enterprise demand say? Is this like asking iOS or Android? Is there a right or wrong answer?

So we are here to inform and provide clarity. Today we’re looking at two popular programming languages, Scala and Python, and comparing them in the context of Apache Spark and Big Data in general.

Read on for the comparison. I’m at a point where I think it’s wise to know both languages and roll with whichever is there. If you’re in a greenfield Spark implementation, pick the one you (or your team) is more comfortable with. If you’re equally comfortable with the two, pick Scala because it’s a functional programming language and those are neat.

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Uncommenting XML from C#

Published 2021-05-05 by Kevin Feasel

Joy George Kunjikkur needs to remove some XML comment tags:

Requirement 

As part of the installation, some XML fragments (eg: <authentication>) need to be uncommented in web.config file based on the environment,. This can be done either via PowerShell or C#.Net as this has to be triggered from MSI installation. Never during the runtime of the application.

Alternatives

We can either do string-based detection and replace it. Or use XML parser of .Net. Since the string parser is complex, let us stick with the .Net library to replace it.

Read on for one way to do this.

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A Modern C++ Kafka API

Published 2021-04-15 by Kevin Feasel

Kenneth Jia and Benedek Thaler announce an open source library:

Morgan Stanley uses Apache Kafka® to publish market data to internal clients and to persist it for replay purposes. We started out using librdkafka’s C++ API, which maintains C++98 compatibility. C++ is evolving quickly, and we wanted to break away from this compatibility requirement so we could take advantage of new C++ features. This led us to create a new C++ API for Kafka that uses modern C++ features (i.e. C++14 and later). We’ve open sourced this client and hope you enjoy it.

Click through to learn more. What interests me about this is that most of the other languages’ support for Kafka (for example, .NET) is based off of librdkafka. I don’t know if there’s any benefit to moving to this new library.

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Predicting Insurance Prices with ML.NET

Published 2021-04-12 by Kevin Feasel

Chandra Kudumula shows off ML.NET:

There are three ways to begin with ML.NET

– API Model: You can start ML.NET through a Framework API and write code in C# or F#
– GUI Model: Use ML.NET Model builder in Visual Studio.
– CLI Model: For cross-platform development like Mac and Linux, use ML.NET CLI.

Let’s get started with API Model for predicting the insurance premium using ML.NET Framework.

I’m using Microsoft (MS) Visual Studio 2019 and creating a Console Application. Be sure that you have the latest version of VS and that .NET 5 SDK is installed.

Click through for the demo in Visual Studio using C#.

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Embracing the XML

Published 2021-04-06 by Kevin Feasel

Grant Fritchey has some advice:

While XML is, without a doubt, a giant pain in the bottom, sometimes, the best way to deal with Extended Events is to simply embrace the XML.

Now, I know, just last week, I suggested ways to avoid the XML. I will freely admit, that is my default position. If I can avoid the XML, I will certainly do it. However, there are times where just embracing the XML works out nicely. Let’s talk about it a little.

Just need to do a little victory dance here. I didn’t explicitly say “embrace the XML” but close enough…

I think the biggest problem DBAs have with XML is that they end up treating it like a dreadful task: I need to shred XML for an extended event. But to do that, I have to learn how to query it using this quasi-language, and so they get stuck trying to fuss with something somebody else did, moving symbols around in the hopes that they get the right incantation. By contrast, a day or two really focusing in on how XQuery and XPath work would clarify a lot and make the process much simpler.

There is a fair counter-point in asking how often you’ll use this, and if the answer is “probably never,” then poke through and just try to get it working. But I’ve got a bit of bad news: “probably never” is probably wrong.

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Retrieving Counts of Cosmos DB Collections

Published 2021-04-01 by Kevin Feasel

Manoj Pandey shows how you can retrieve counts of records in Cosmos DB using the .NET client:

Here in this post we will use C# .net code (for beginners like me) to see how to:
1. Connect to a Cosmos DB instance
2. Get list of all Databases in a Cosmos DB
3. Iterate through all the Databases and get the list of all Collections (or Tables)
4. Get COUNT of all documents/items (or records) in these Collections

Click through to see how.

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