Manipulating Data With F#

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I’ve been working with our corporate website for the past few days. I’m trying to get analytics for some A/B split testing. As a part of that, I got to play with some really neat FSharp features. Type providers have allowed me to use a snippet of json to build a type hierarchy without doing the heavy lifting myself. And recursive sequences allow me to consume a paginated webservice as though it was a single data set.

Bringing My Customers Together

The data I’m currently interested in is, as far as I can discover, only available by asking each Hubspot contact for their list of form submissions so I can count the number of submissions to each form. But I can only ask for 100 customers at a time. The response will tell me if I can fetch more and the vid-offset I can use to get to the right spot in the pagination.

let rec Contacts offset =
   seq { let data = HubspotContacts.Parse(Http.RequestString("http://api.hubapi.com/contacts/v1/lists/all/contacts/all",
                                                             // apikey not included ;) 
                                                             query=["hapikey", apikey; "count", "100"; "vidOffset", offset],
                                                             headers=[Accept HttpContentTypes.Json]))
         yield! data.Contacts
         if data.HasMore then
            yield! Contacts (data.VidOffset.ToString())}

What’s happening? The seq structure creates a seq computation (think IEnumerable) and allows us to write code that generates a seq. The yield! keywork takes a collection and doles each element out in turn. If we find the collection has more, we yield the results of a call with the offset. This means our first call will use the offset “”.

Types are your friends

FSharp type providers are wonderful. They can, at compile time, parse out some code and generate a type tree. In particular, using the FSharp.Data library I can give it a snippet of JSON and get back a strongly typed parser.

// I'm leaving a lot out of the json snippet.
// You don't need to see the details of my customer data
let [] ExampleResponse = """ { "contacts" : [ {"form-submissions": [{ ... }]}
                                                       { ...} ],
                                        "has-more" : true,
                                        "vid-offset": 1234 } """
type HubspotContacts = JsonProvider

Reductio ad absurdum

The only thing left for me to do is take this and map / reduce my way to a collection of form-ids and counts.

Contacts ""
// Transform from a seq of contacts to a seq of form submissions
|> Seq.map (fun c -> c.FormSubmissions)
|> Seq.concat
// Extract the form id
|> Seq.map (fun fs -> fs.FormId)
// Collect the counts of unique formIds
|> Seq.fold (fun s v -> Map.tryFind v s with
                        | Some(count) -> Map.add v (count+1) s
                        | None -> Map.add v 1 s) Map.empty
// Report the FormId and Count
|> Map.iter (fun formId count -> printfn "%A %i" formId count)
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Are You Doing Anything Real With It?

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I’ve been playing with Clojure recently and loving it. However, most of the stuff I’ve been doing with it recently has been Exercism.io, and not actual application code. To rectify that, I pounded out (slammed my head against a few problems) a simple application (sure, now that it’s written) to get my secret feed from NSScreencast and download the videos.

Two Great Houses

Reading a feed and downloading movie files is very simple on the surface. There are two things complicating the issue, but they are two very important parts. First, feeds are stored as RSS, and XML is best treated as a tree data structure, not as text to Regex over. Second, NSScreencast uses a CDN, but that means the video URLs return a redirect.

The Forest of Xml

The Clojure community has taken a shining to using Zippers for traversing large trees of data. Xml is just a tree of data. Once you parse the damn thing. Fortunately, Clojure has a few libraries for handling this; Clojure.xml, Clojure.zip, and Clojure.data.zip.xml.

Our Imports

            [clj-http.xml :as xml]
            [clojure.data.zip.xml :as zip-xml]
            [clojure.zip :as zip]

Building a zipper

Eventually, I need to have an xml zipper from the Clojure.zip library. For that to happen, I need to give Clojure.xml’s parse an input-stream based on the feed’s url.

(defn make-feed [uri]
  (-> uri
      input-stream
      xml/parse
      zip/xml-zip))

The feed I process is build the following:

(def feed (make-feed "https://nsscreencast.com/private_feed/«secret_key»?video_format=mp4"))

Yeah, I’m not giving you my secret key. Go subscribe! They are good!

Traversing a zipper

Here’s an example of the xml we are navigating. This is taken from NSScreencast’s free video feed and only has the first two entities.

<?xml version="1.0" encoding="UTF-8"?>
<feed xml:lang="en-US" xmlns="http://www.w3.org/2005/Atom">
  <id>tag:nsscreencast.com,2005:/feed</id>
  <link rel="alternate" type="text/html" href="http://nsscreencast.com"/>
  <link rel="self" type="application/atom+xml" href="http://nsscreencast.com/feed"/>
  <title>NSScreencast (free videos)</title>
  <updated>2014-01-29T00:00:13Z</updated>
  <entry>
    <id>tag:nsscreencast.com,2005:Episode/93</id>
    <published>2013-09-26T10:02:32Z</published>
    <updated>2013-09-26T10:02:32Z</updated>
    <link rel="alternate" type="text/html" href="http://nsscreencast.com/episodes/87-xcode-5-autolayout-improvements"/>
    <title>#87 - Xcode 5 Autolayout Improvements</title>
    <content type="text">This week we have another free bonus video on the improvements that Xcode 5 brings to Autolayout.  As something that has been quite obnoxious to work with in the past, many people dismissed auto layout when it was introduced to iOS 6.  With these improvements it is much more friendly and dare I say... usable?</content>
    <link rel="enclosure" xml:lang="en-US" title="Xcode 5 Autolayout Improvements" type="video/mp4" hreflang="en-US" href="http://nsscreencast.com/episodes/87-xcode-5-autolayout-improvements.m4v"/>
    <author>
      <name>Ben Scheirman</name>
    </author>
  </entry>
  <entry>
    <id>tag:nsscreencast.com,2005:Episode/91</id>
    <published>2013-09-19T10:01:59Z</published>
    <updated>2013-09-19T10:01:59Z</updated>
    <link rel="alternate" type="text/html" href="http://nsscreencast.com/episodes/85-hello-ios-7"/>
    <title>#85 - Hello, iOS 7</title>
    <content type="text">To celebrate the launch of iOS 7, here is a bonus free screencast covering a few of the concepts in iOS 7 such as the status bar behavior, tint color, and navigation bar transitions.  We'll also take a look at Xcode 5 with a couple of the new features, including the integrated test runner.</content>
    <link rel="enclosure" xml:lang="en-US" title="Hello, iOS 7" type="video/mp4" hreflang="en-US" href="http://nsscreencast.com/episodes/85-hello-ios-7.m4v"/>
    <author>
      <name>Ben Scheirman</name>
    </author>
  </entry>
</feed>

Once I have the zipper for the feed, I need to traverse the feed’s tree. What I want eventually is a list of file names and urls for that file. the file name will come from the feed, but I need to find the url from traversing all entry tags, their child link tags, but only the link tags with a rel="enclosure". But honestly, I only care about the href attribute.

(zip-xml/xml-> feed
               :entry
               :link
               [(zip-xml/attr= :rel "enclosure")]
               (zip-xml/attr :href))

Once we have this, we need to find the file name. Anything between the last / and the only ? is the file name. The way clojure returns Regex matches, however, is a match followed by the group. So, if we spread out the regex to match the whole Uri, we have the two peices we need for further processing. Well, we need to map over first before doing anything because of the way re-seq returns data.

(defn link-file-pairs []
  (->> «feedTraversal»
       (map #(re-seq #".*/(.*)\?.*" %))
       (map first)))

Looking in the wrong place

While Clojure’s input-stream is capable of handling a uri, it has some trickyness with SSL urls and more importantly, the redirect to the CDN is handed back as a document I have to parse by hand. Fortunately, clj-http.client handles all this for us. We’ll require the lib as client. To copy a file from a uri to the disk, we use our copy-file routine.

(defn copy-file [[uri file]]
  (with-open [w (output-stream (fullname file))]
             (.write w (:body (client/get uri {:as :byte-array})))))

the function client/get returns a map of data, and we only care about the :body. We ask for the body to be returned as a byte-array with {:as :byte-array}. with-open is used to close the output-stream once we’re done. And since we are using this to map over a vector of uri and file, we will destructure the vector in the argument list.

Fleshing out the rest

The main algorithm of the downloader is to get a list of link-file-pairs, filter the videos I’ve already downloaded, and copy all the files. I tag a doall to ensure any lazy seqs actually execute.

(defn -main []
   (->> (link-file-pairs)
        (filter not-downloaded)
        (map copy-file)
        (doall)))

Determining if a file is downloaded is fairly simple. Figure out the full path of the expected file, make it a file object, and ask if it exists. But I want the inverse of exists, so we’ll tag a not on the end.

(defn not-downloaded [[uri file]]
  (-> file
      fullname
      as-file
      .exists
      not))

What’s in a name?

I’ve already downloaded some files, so I wanted to make sure they had the same naming scheme. Also, the fullname function knows where on my machine the files are supposed to go. The details arent interesting as the prefix makes life more difficult than it needs to be.

(defn zero-pad [n number-string]
  (->> (concat (reverse number-string) (repeat \0))
       (take n)
       reverse
       (apply str)))

(defn prefix [file-name]
  (clojure.string/replace file-name #"^\d+" #(zero-pad 3 %)))

(defn fullname [file]
  (str "C:\\Users\\bjball\\Videos\\NSScreencasts\\ns" (prefix file)))

The Details

The code is available on Github. As a part of a literate programming exercise, the structure is all laid out below.

(ns nsscreencast-fetcher.core
  (:use [clojure.java.io :only [output-stream as-file input-stream]])
        (:require [clj-http.client :as client]
                  «xmlDecls»))
«makeFeed»
«feed»
«linkFilePairs»
«fullName»
«copyFile»
«notDownloaded»
«main»
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Principles In Practice – It Will Go Wrong

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It’s Murphy’s Law. If it can go wrong, it will. What’s your application’s opinion on errors? If we take a stance on errors, these principles will tell us exactly how the application will behave. Shared understanding means less miscommunication. Here are some of the things I’m talking about.

Operators have the accurate information – your data is already wrong

If you’ve ever heard the following conversation, you know data entry will always be out of sync with the real world. “I know the database is telling me that bus 7 has transmission 8 installed, but I’m looking at transmission 3. Don’t tell me I can’t uninstall transmission 3, because I just did.”

What does that mean for implementation? Favor “soft validations,” warning that errors are present, but allow overrides. If I have a misallocated part in the database, I need to uninstall it from where the database “thinks” it is and mark that uninstall as something needing follow up by people in the field.

It’s all fun and games until someone dies. – The data must have integrity

Particularly in the medical field, the configuration of a medical device should be exactly what you intend with no mistakes or corruptions. Corrupt data can kill. Also, data must meet certain validations to be used, but can fail during editing.

Never write over the data file. Always write to a shadow file, test the integrity and in one atomic action, move the new data file over the old one. If there is ANY failure of integrity, the old data file is a safe fallback position.

In addition, the internal data structures might be “persistent” allowing undoing to a known good state if any operation fails an integrity check. Some transient operations might lead to bad values, like changing a medical dosing schedule might temporarily exceed safe dosages within a time frame, but you should not exit the schedule edit until the schedule validates.

If it crashes, I can use the browser, right? – The application must stay running

This is useful for kiosk or embedded applications. However some long running applications also need to handle failure.

Use multiple executables. The less an application does, the less likely it is to crash. In addition, a supervisor application can restart parts of the application that fail. Operations with risky components like using third party drivers or that can enter bad states because of bad data can run in their own sandbox and die if they ever enter a corrupt state.

There is real money involved

Real money requires an audit log. In addition, duplicate submissions are a killer and should be identified ASAP to avoid duplicate charges.

Operations, like purchases and fulfillments, are seen and recorded as first class data. The engineering team may lean on CQRS for these operations. Operations may be given an identifier early in the process. For example your cart my always have a “next order Id” so commands may be made idempotent preventing duplicate submissions.

Take a bit and think about how your application can fail and what can go wrong. Pick your battles and identify the ones that are the most likely and the ones that cause the most havoc. How are you going to handle them?

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Principles of Architecture

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There is no correct software architecture. But there are an unlimited number of ways to incorrectly architect your software. The best we can do is state some principles and use those to help narrow the solution space of all possible architectures. This will help us identify a more correct architecture.

Architecture – a quick definition

Building Architecture is a combination of two things, making the building suitable for purpose and making the overall structure pleasing to the eye.

Making a building suitable for purpose is mostly dividing the space in to boundaries. Like rooms are often grouped near one another. Some structural considerations may help this grouping, such as bathrooms being above the kitchen to limit the number of wet walls. Some rooms may have internal subdivisions like nooks and archways that don’t limit the flow or utility of a space but visually define these regions. This defines the utility of a building.

Aesthetic considerations help make the building feel as it belongs. This means it fits in the surrounding landscape as well as feels balanced and consistent with itself. The balance and feel contribute to the habitability of a space.

Utility and Habitability in Software

Software architecture also controls the utility and habitability of a program.

Software Architectural utility is not the UX, but the software’s ability to perform its tasks quickly enough, reliably enough, and a host of other so-called -ilities. This is done by determining if you need extra caching for speed, separation of the active data set from the reporting data set, splitting the application in to multiple programs to better handle failure, and interfacing with other systems. And that’s just a start!

Software Architectural habitability is about the ease of development. Simple changes should be simple. Changes that depend on multiple business concepts interacting should only be as complex as those interactions. This is done by being deliberate about what code interacts with other code, by drawing boundaries between software concepts that reinforce boundaries between business concepts.

These forces can be in tension. Adding robustness to an application can make changes harder. Making it more flexible can degrade performance. Focusing solely on making easily changeable software if fine for small scale software. Wringing every last ounce of throughput is perfect for less complex software. Finding the balance is the art of Software Architecture.

Principles for Improving Communication

If you need someone called “Architect” on your project, the odds are you have a team larger than the two-pizza rule. That means that several decisions a day are going to need the architect to be there, and some times she can’t be present in person. Be stating not only the design goals but what purpose they serve, the architect empowers the team to make correct choices when they find themselves on their own.

It isn’t sufficient to say the software must be robust. But if we say minimize the impact of failure on non-related operations and enable a manual retry of failed transactions we are clearly stating what we mean by robust. When dealing with a design decision I can now ask myself a few questions to guide my implementation.

  1. Does failure impact other users?
  2. Do I have enough information to recreate this request if it fails to complete?
  3. When I fail, can I undo the partial operation?
  4. Are my operations Idempotent?

By stating the outcomes desired instead of the means we use to get there, the architect prevents the same problem being addressed by nothing more than a bunch of null checks and try/catch blocks.

It’s Only Business

Theses principles should come from the business case for the software. How many users are you supporting at once? Are they _occasionally connected_ or always connected? What is the impact of failure on a sale? The impact of failure on trust in the system? How about the impact of failure in the lives of thousands of children? Will someone die if your software falls down or corrupts data?

What are the reasons for your architecture choices? Have your design choices helped or hindered those goals? Is there tension between the design impacts of your business goals? Do you have some design changes to go deal with?

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It’s not been abstracted away yet, has it?

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There is a bug in my code that I finally squashed last week. I had been visiting it and kicking it down the road for a couple of weeks as the feature is still being written. When I move to a specific view in our application, I needed a TextBox to gain focus. When navigating away from this view, some button or other will grab focus so returning will not show the TextBox as having focus. The view knows when it is being activated, so why can’t I just tell it to focus on the TextBox then?

A Timer? Really?

Elsewhere in the inherited code base, I saw them do essentially that. When the view is activated, tell the TextBox to focus. Only they used a timer with a very short duration. This is obviously a code smell, so I did it very differently. Here’s some sanitized WPF code to describe what I saw and what I did.

Their Code

A DispatchTimer runs on the UI thread. So I made an assumption the only reason this was being done was to make sure UI code was happening on the UI thread.

public void FocusTextBox(object sender, EventArgs e){
  var time = new DispatcherTimer{ Interval = TimeSpan.FromSeconds(0.01) };
  timer.Tick += delegate {
    timer.Stop();
    if(FocusedTextBox != null){
      FocusedTextBox.Focus();
      FocusedTextBox.SelectionStart = FocusedTextBox.Text.Length;
    }
  };
  timer.Start;
}

This works. It makes my skin crawl because it uses a timer, seemingly only for thread hopping.

My Initial Version

I just told the Dispatcher to run some code for me. The simplest way to get code running on the main thread.

public void FocusTextBox(){
  Action makeFocused = delegate {
    if(FocusedTextBox != null){
      FocusedTextBox.Focus();
      FocusedTextBox.SelectionStart = FocusedTextBox.Text.Length;
    }
  };
  Dispatcher.Invoke( DispatcherPriority.ApplicationIdle, makeFocused );
}

But, as the documents say,

Events and Sequence Diagrams

GUI applications run via an Event Loop. We all but ignore this by hiding it behind APIs like Application.Run that handle the loop for us. Our base classes wire in to the event loop allowing buttons to register their touches. All this abstraction gives us an illusion of concurrency. But it isn’t really concurrent.

If you debug a .NET application, you will notice that a line of code that triggers an event will immediately stop the execution of the current method and start executing the event handler.

I was using the Dispatcher to ensure I was working on the UI Thread, but what if I started on the UI Thread?

I’m not 100% positive, but here’s the theory for what’s happening:



* A touch down event changes tab


* This causes the tab selection index to change triggering an event handler


* The event handler sets the focus on the text box


* and returns control to the tab control


* The tab control finishes


* and returns control to the event loop


* which processes a touch up event changing focus

joy.

My Final Version

The fix was simple. I need to add an event to the queue without interrupting the current pass through the even queue. Fortunately, the Dispatcher allows us to enqueue a bunch of operations and even manipulate them in flight so to speak via a DispatcherOperation. Let’s try calling BeginInvoke on the dispatcher instead!

public void FocusTextBox(){
  Action makeFocused = delegate {
    if(FocusedTextBox != null){
      FocusedTextBox.Focus();
      FocusedTextBox.SelectionStart = FocusedTextBox.Text.Length;
    }
  };
  Dispatcher.BeginInvoke( DispatcherPriority.ApplicationIdle, makeFocused );
}

And it works. The touches are fully processed before I try to set focus. And I don’t use a timer for flow control.

Takeaway

The main takeaway is the event loop still exists, even if our abstractions try to hide it. Event based programming is amazing. But we must remember that it only creates an illusion of concurrent programming. All of those actions are still happening sequentially. It does pay to really understand the arcane secrets programming frameworks use to enable their abstractions.

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Music as a Metaphor

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Music is a highly structured art form… usually. This structure makes use of repetition and variation of form. Music can be monophonic or polyphonic, one voice or many voices interacting with each other. That’s what makes it interesting as a way of exploring code structure.

Symphonies

A Symphony is a collection of songs, called movements, connected in some manner. They share a collection of themes and other musical ideas. But each song operates in its own reality.   Each song has its own musical key, tempo, and time signature giving each movement a very different feel. Each song still serves to bolster the Symphony as a whole.

Some applications have such different responsibilities we express each responsibility as a different executable program. A time sheet software may have a time entry client, a time entry server, time code management, a reporting system, and a payroll system. The themes that string everything together are the Ubiquitous Language and shared data interfaces. Each program has a shared understanding, but can act on that understanding in the manner that best fits its unique responsibilities to the application as a whole. In addition, some programs/services may serve to alter the data from one format to another, such as waiting until generating invoices to transform from a format used by most of the application to the format needed by our third party software.

Verse-Chorus Form

Your basic pop song has an internal structure called Verse-Chorus form.  The verses have similarities to their internal structure but vary differently in the content. The variance is usually the words of the verse. The chorus is the same, used to break up the verses.

We can see Verse-Chorus form in an app with several data screens, like the time entry client.  Each screen is a Verse stitched together with both a data layer and navigation framework, the Chorus.

On occasion, a song has a radical change called the Bridge. This can alter the musical key as well as rhythmic underpinnings and has little similarity to the rest of the Verse-Chorus form but serves to add interest before returning to the original structure. As our time client grows, we find reports and off-line syncing that are important to our application, but are structurally very different from itself.

Canon

A Canon is a way of manipulating a melody. The simplest example would be Row Row Row Your Boat, where the melody is time shifted by one third. When this happens twice, for a total of three instances, we get a special class of canon called a Round and can repeat the layered melody Ad infinitum.

In our time application, we can think of the canon as the series of transformations we need to apply to our employees’ time data this billing period.  We collect, group, transform, and collect again.  In C# this can be a rather long list of Linq operations.  In SQL, a very complex query.  But a lot of the data accumulation and transformation can be carefully done in parallel.  Much like a canon.

Why Care?

This is an incomplete metaphor. I wouldn’t use it as a means of laying out your code base. Instead, I can see it used to seed discussion about similarities and structure. By understanding that parts of your application have similarities and differences, the hope is we can group our code in a way that helps separate responsibilities, give clarity, and let developers quickly find the code they need.

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Programming is Math?

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This sculpture is known by some students as the Cecil T. Lobo Whatzit. This sculpture was installed on the Rose-Hulman campus by the Civil Engineering Department as an example of 17 different the steel joints. It is an amazing technical challenge to find harmony and balance with in the constraints of 17 steel girder joints, all “Golden-Gate Red”.

Quite frankly it looks like junk to my untrained eye.

I had a conversation one morning where we were talking about art for the sake of art. We talked about collaborations and other art projects that are interesting to those steeped in the art form, but not to the uninitiated.

One phrase I keep hearing stated as a universal truth is “Programming is Math.” I’ve tried to ask people what they mean by this, but I have yet to find someone who doesn’t think I’m trolling them. The problem is EVERYTHING is Math. Economics is Math. Engineering is Math. Architecture is Math. Even Painting is Math.

But everything is also Poetry. Ask a Poet.

I was trained as an Engineer. Capital E. I took classes on fluid dynamics, forces on static structures, and circuit design. I see the world as a list of Knowns specific to a problem, a bunch of Given universal truths and equations, and a solution I’m attempting to Find. Elegance never entered in to that much. But then I began seeing how solutions work for real people, how they impact their lives. Defining the problem became much more interesting. Math was only something I used to get there. In programming that was usually Algebra, Boolean Logic, and Trigonometry.

Okay, lets get back to software. There are a bunch of techniques we use when architecting software. There are books and books of patterns on the subject. We try to find a pattern to match the entire solution, but we will fail. That’s not to say we shouldn’t understand these techniques and explore them, just that we shouldn’t confuse a study with art just because it is well done.

The problem I have with this is first and foremost, it is seen as an obvious truth that needs to be stated, but once stated is self evident. When making such a statement, you should be offering help on the road to enlightenment, not merely shouting from the mountain top that you have achieved satori. It annoys me that I’ve yet to find a way in to this secret understanding of Math having always been horrible at wrote computation we teach kids in American Math classes. But it also feels counter to what I have come to understand about software in my 13 years as a professional practitioner.

“The Second Law of Consulting: No matter how it looks at first, it’s always a people problem.” – Gerald Weinberg

The things that make my life difficult aren’t a lack of technical choices, but understanding the implications of how those choices fit together. Especially if I wasn’t there to participate in the evolution of thought and circumstance.

The thinking of Programming as Math feels like we are suborning the technique to the expression. The art is getting lost in the technical aspects of the art form. I want to say communication and clarity to my fellow developers and collaborators is far more important than technical details of my solution. There are techniques that help me do that, but only if they serve the communication.

And I still can’t see where programming like this is Math as I understand it.

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Architecture Vs. Structural Engineering

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We like to use a metaphor comparing software design to building architecture. Some people accept that this is flawed. Others cling to this metaphor too tightly, seeing developers as little more than tradesmen installing carpet in a new skyscraper.

A Building Architecture project includes a Structural Engineer. Her job is to ensure the building stands up. Her job is to determine what materials are used in the wall interiors. Her job is to make sure the windows will withstand the forces of straight line prairie winds against the 30th floor.

She is active in the design. The architect defines taste, purpose, form, function, and values. The Architect’s role is to define the spaces where she works. This, in my mind, is a very different role in software. I posit that most conflict between Architects and development teams stem from misunderstanding the role of the Structural Engineer.

Lets look at a large system. I have a web application that is used to track employee time spent on projects and turn that in to purchase orders. We have concerns about using this tool on client computers exposing sensitive data. We need to manage project membership. We would also like to use that to build employee and company “résumés” used in explaining our expertise to our clients. I’m not picking this real example because I think our current incarnation of this tool is wrong, but because this tool is an example of a large system that has many responsibilities.

What should I as the Architect spend my time doing? Should I start mandating the use of certain threading patterns? Building the ERD for the highly normalized database? Or start determining the bounded contexts, core contexts, use cases, external constraints, target response times, and security requirements?

I would get my Tech Leads in to a room and discuss how each context needs to talk with the other contexts. I would focus on how the contexts are realized and coordinate with each other. I would let my Tech Leads figure out the internals.

How do I make sure I understand the design tensions between the contexts? I would need to work on several teams, pairing with developers who work deep in the code to find where our abstractions are breaking down. An building architect spends time on site during construction for just this reason.

But I would make sure the teams are still talking, and still hitting those request times. They are my system engineers. While I may or may not know better than them as a developer, my job is to teach them to make the right choices, not make decisions for them.

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Why I Blog

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I told a friend of a plan. It was one of those crazy master plans that will probably change to world. He seemed nonplused. I said, “How about a writers workshop for blogging?” He said, “I don’t like writing. So why should I come?”

I won’t convince a veteran of the “Blog Battles” of ’aught 11 and ’aught 12 like him that writing is fun if he has already decided it isn’t. But maybe I can convince him, and maybe you, that blogging is important. And I’ll try by sharing with everyone why I blog.

To think things through

When approaching an idea that I may not quite completely understand, I don’t always consider it from all angles without some sort of framework. Blogging is one of the frameworks I use. By trying to think through an explanatory narrative, I come to understand what was a vague notion before.

To find later

I have come across the occasional hard fraught nugget of knowledge. Unfortunately, I have mind that is quirky about what actually sticks. Fortunately, I have referenced my blog myself.

As a shorthand for explaining to others

Nothing makes me happier when having a chat with my colleagues and being able to say, “Have you tried #{thing}?” Bonus points if I can point them to a blog post where I actually have something constructive to say.

To participate with the community

I look forward to the SEP blog battles. Not only is it fun to think about how I’m going to approach the topic, but I love reading the posts my coworkers write. It is wonderful to see a new perspective from the thoughts I’ve been having.

Because I have time

I used to spend evenings for a month at a time prepping presentations. I wrote code while watching TV with my Wife. I’m now a Dad. I would rather spend time with my Wife and Daughter than a laptop. But I still read. And since I have my phone at almost all times, I can write when my baby Daughter sleeps on my shoulder. Like now.

To improve my communications

The most important thing I do all day is communicate. Usually, it is written communication. I write for the compiler. I write to my friends in chat. I write to my team and company in email. I write code that needs to communicate to not only only my other team members, but myself when I come back to this code in the future Writing is a skill and blogging is a way to practice.

This is why I write. Your motive for blogging or not are your own. But I would recommend you occasionally write something.

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Checks Over $10,000 Require Two Signatures

work safe

When I get a check from SEP, there is a note and a blank line by Traci’s signature. It states that any check for more than $10,000 needs a second person to agree. While I’m sure there are some fraud prevention reasons this is a standard business practice, it serves a better purpose in our Demming based world view. We assume Traci is doing her best and has the truest of intentions,
but it sets a line on the sand for when she should get a collaborator. It is one thing for the IT staff to buy a new workstation for a couple grand. Once we are acquiring Oracle licenses it is nice to have a second person to say, “yes, there is no better way to achieve this goal other than to give Oracle everything in our bank account.”

We are reading Lean Architecture for Sep’s book club. It seems to be a good book because there is some agreement and some disagreement with its contents.

One such disagreement was over separating modules basd on teams. Why make such an artificial distinction? Isn’t it far too heavy to have to hand off a feature from a business layer team to a UI team to create a new feature? Yes. But that’s not what we are talking about. We are talking about distinctions of usage, not necissarily infrastructure. The graphs verses the import logic For example.

It was also mentioned that we have yet to talk about changing the architecture. The pithy answer is, of course, you change it every time you write any new code. The less pithy answer is any time another team is impacted by your code.

Crossing from one module to another is the trigger. Since it will cause changes on the code of another module, I should not make these design choices alone. It is a firewall against the inevitable descent in to the big ball of mud. It is the second signature line on the check.

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