April 8th, 2014

# Forked processes, concurrency, and memory problems

Last week I expressed my doubts about Unicorn (and the idea that it uses processes, therefore it uses Unix, therefore it must be good). Here is another article that looks at Unicorn, and in particular the memory consumption that goes along with forked processes:

Unicorn uses forked processes to achieve concurrency. Since forked processes are essentially copies of each other, this means that the Rails application need not be thread safe.

This is great because it is difficult to ensure that ...

April 7th, 2014

# Yahoo has some very stupid programmers

Good lord, why is this developer at Yahoo so slow on the uptake?

Thank you for your submission to Yahoo! Unfortunately we are unable to reproduce the bug due to insufficient information. Please provide us with a proof of concept or any other additional evidence required to reproduce the issue.

** The attacker would have to know the invitation id correct?

One has the sense that the person reporting the bug is shocked by the lack of concern shown by Yahoo:

d4d1a179c0f3 changed ...

April 7th, 2014

# The Clojure workflow still suffers and the REPL is not a cure all

Stuff like this happens to me:

Here is a scenario that you might recognize. You’ve done a pretty substantial refactor, including new dependencies in project.clj. You need to bounce the REPL. Knowing that this will take forever you immediately switch to Prismatic. 15 minutes later you look at your Emacs again where you notice that there is a syntax error so the REPL didn’t launch. You parse the impossibly long stack trace and fix the bug. cider-jack-in again and switch back ...

April 6th, 2014

# Behavior driven development is broken

This is very good:

If it takes you ten lines to communicate the idea of adding subpages, then you’ve wasted my time. I’m not alone in thinking this. BDD expert Elizabeth Keogh tells us:

“If your scenario starts with ‘When the user enters ‘Smurf’ into ‘Search’ text box…’ then that’s far too low-level. However, even “When the user adds ‘Smurf’ to his basket, then goes to the checkout, then pays for the goods” is also too low-level. You’re looking for something ...

April 5th, 2014

# Why has Linux not seen more forks?

Strong language, and strong opinions, as always, from Linus Torvalds. Now that I think about it, isn’t it amazing that Linux remains stable, even after all these years. I remember someone predicting, years ago, that Linux would split apart into a million useless forks, just like Unix did a long time ago. But that never happened. There are a lot of distros, but the kernel remains 100% under the control of Torvalds. That must mean people trust him. And ...

April 4th, 2014

# Using Gloss to change bytes into Clojure data structures

Interesting:

I started creating a very simple protocol to allow clients to connect via telnet. So it is:

PUT LSA |*

We have two main commands, PUT and LSA. For PUT, author is the guy speaking, via is who noted it, and the fact is the statement itself. And for LSA command, you can pass the author’s name and the system will return all the facts spoken by the author. * means you want to read all the facts.

Any other command ...

April 4th, 2014

# Hashmaps versus btrees

Interesting:

Unsuprisingly, a hash map performs far and above the rest. This is to be expected, mapping is exactly what hash maps are for and, in most situations, they should perform insertions and lookups with amortized O(1) time complexity. However, for situations where you made wish to preserve order, a tree may be a better choice. For that, you can see that a well-tuned btree was outperforming a red/black tree by more than 2 times.

As memory architectures begin to behave more ...

April 4th, 2014

# Just Libraries – the composition of small apps

Clojure favors the composition of small apps. The Clojure community has shown a resistance to monolithic frameworks like Rails. Now Immutant is moving further down the small app road.

For its second major release, Immutant will simply be a collection of libraries, one for each of the commodity services currently available to applications using an Immutant 1.x container: web, scheduling, messaging, caching, and transactions. These services will be provided by the following underlying components: Undertow, Quartz, HornetQ, Infinispan, and Narayana, ...

March 31st, 2014

# The worst web site ever: healthcare.gov

What an incredible disaster. I say this as a professional who develops websites. Several states, such as Kentucky, built their own web sites, which have worked great. But the Federal site, even 6 months after launch, remains a disaster.

This is the error message I got when I just now tried to sign up:

Today’s the last day to sign up for Obamacare if you’re planning on using the healthcare.gov website. Unfortunately for people who tried to log onto the ...

March 31st, 2014

# Java 8 has an Optional to deal with NullPointerException

I don’t think I am impressed with this. The idea is borrowed from Scala. I have no love for Java or Scala, and I only follow Java because it impacts Clojure. If this enables Clojure to do something clever with NullPointerException, then maybe I will reevaluate this.

Source

March 31st, 2014

# Content Security Policy and Ruby and Clojure

Although I love Clojure, I must admit that Ruby and Rails have an impressive depth of gems to help with every aspect of web development, including security. John P Hackworth recently wrote of the weakness of the Clojure eco-system, although his criticism is also an attack on the whole of idea of “small libraries that compose well” which amounts to an attack on the idea of “small pieces, loosely joined”. Clearly, good security can be achieved with small libraries that ...

March 31st, 2014

# Using Clojure to build a microservices CMS

Many of us become cynical about technologies that promise big breakthroughs in productivity, so we become overly careful in our choices, but this is a good question for managers to always be asking:

“Why would a large organisation with a mix of technologies and legacy systems want to muddy the waters with a completely new language?”

If you want to make the conservative choice, and stick with what you already have, you should be able to articulate the reasons as clearly as ...

March 30th, 2014

# eat food for food in foods when food isnt ‘chocolate’

Of the many attempts to re-invent Javascript, the mostly puzzling to me are those that do not fix any problems, and then invents some more. I realize there is a strong desire to borrow ideas from Ruby and bring them to Javascript, but where one can’t do that cleanly, one shouldn’t do it at all.

It’s a tool, that is all. Ambiguous code is a poorly thought out contrived example with a simple solution. To me, this: eat food for ...

March 30th, 2014

# Chris Granger: more problems with object oriented programming

At this point the evidence against object oriented programming seems overwhelming. I’ve linked to many articles here on this blog. Chris Granger offers another take on this issue:

Programming is unobservable

We can’t see how our programs execute. We can’t see how our changes affect our programs. And we can’t see how our programs are connected together. That basically means we can’t observe anything. The state of the art in observability is a stepwise debugger, which forces us to stop the world ...

March 30th, 2014

# NoSQL is a new of doing things, not a drop-in replacement for SQL

I like this:

Both NoSQL and Erlang had a burst of use and interest but because they were seen as silver bullets. Soon people realized you couldn’t simply translate your imperative code to Erlang and see improvements but instead regressions. Additionally, throwing your relational data at a NoSQL databases caused the same.

I feel the NoSQL culture and programmers haven’t retracted to the core yet as much as Erlang. Though Erlang may see another surge of misuse and misinterpretation now with the ...

March 27th, 2014

# The advantages of Ruby on Unicorn

This is an interesting way to look at things. Since so much of Ruby code is not thread safe, the fact that Unicorn spins up processes that don’t talk to each other is the most safe way to get concurrency in Ruby. That is a good point, though it is equivalent to saying “Since the code is broken, the the application server to do something weird to compensate for the brokenness.” Clearly, some people have good results with this, though ...

March 27th, 2014

# More negative views about Rails

Rails lacks a story for concurrency. This is written by a Go programmer. Their criticisms are similar to mine, though for me the answer is “use Clojure” and so I end up doing JVM tuning, which is brought up as something scary to keep people away from jRuby. My impression is that the case against jRuby is weaker than the case against MRI Ruby (the C version).

Rails is fundamentally – and catastrophically – slow.

This well-known set of webapp ...

March 25th, 2014

# If Unix is good for Unicorn, why can’t Unicorn handle slow connections?

I wrote about this recently, but I want to add to what I said.

In what I now think of as a famous essay, Ryan Tomayko said “I like Unicorn because it’s Unix“. There must be something to this because the essay has been widely quoted, and I remember it, and I have re-read 3 times in the last 4 years. It had an impact.

And yet, nothing in it convinced me to adopt that model. I rejected it and went ...

March 24th, 2014

# Photon could save PHP

I have been extremely critical of PHP for the last 2 years. See “Why PHP is obsolete“. However, I just stumbled across Photon, which seems to address some of the core problems I see with PHP (especially the lack of any tools for dealing with concurrency):

Why targeting Mongrel2?

Mongrel2 is a very well designed, high performance server developed by pragmatic users who do not like bloated software. The use of ZeroMQ as the communication hub makes it extremely flexible while keeping ...

March 24th, 2014

# The tremendous innovation in Javascript

There is no question that tremendous innovation is happening in the vast extended eco-system that touches upon Javascript. Sadly, I am not much interested in it. Maybe that is because I am not focused on the frontend right now. But also because I’m interested in solving these issues in other ways. All the same, Sam Ruby’s walkthrough of Angular.js is interesting:

We have a model, view, and controller on the client, seemlessly interacting with the model, view, and controller on ...

March 24th, 2014

# Radical workarounds for the limits of MongoDB

Whoa. This gives me interesting ideas:

To reduce lock contention, we decided to run multiple MongoDB instances on one machine and create more granular databases in each instance. Basically data is stored in different instances based on its usage and in every MongoDB instance one database is created for each partner.

Some people hate the fact that MongoDB forces you to do more in your own app, but I prefer designing with those constraints in mind.

This has similarities to ...

March 24th, 2014

# Strange facts about HTML

I feel like I’ve been away from HTML for awhile. 10 years ago I thought of myself as having some design skill, and I did a lot of front-end work, but in 2009, I moved to New York City and worked in some big companies with strict divisions of labor. I was a backender, and backenders are never frontenders. So I’ve been away from the frontend for awhile. It is slowly becoming foreign territory to me. I was surprised to ...

March 24th, 2014

# Why is the technology for blogs so difficult?

Back in 2005, David Heinemeier Hansson offered a Rails tutorial showing how you could create a blog in 15 minutes

:

This was a world changing moment. Everyone I knew watched that video and talked about it. Here was a huge shift away from the overly complex frameworks of the past, and yet here was a framework that really worked, something we could use instead of dealing with the chaos of writing everything ourselves.

You could build blog software in 15 ...

March 24th, 2014

# Once again, the shift to “smart services, dumb pipes”

Yesterday I linked to the article over at Martin Fowler’s website where he wrote about the shift away from complex routing frameworks, towards a system of “smart services, dumb pipes”. Here is one more data point:

At Digg our SOA consisted of many Python backend services communicating with each other as well as being used by our PHP frontend servers and Tornado API servers. They used Apache Thrift for defining the interfaces, clients and as the underlying protocol.

…Coming off the Digg ...

March 24th, 2014

# Often businesses handle a degree of inconsistency in order to respond quickly to demand

Perfect consistency is too rigid for most businesses, and it is painful when technical teams try to enforce this on a company, out of some ideological commitment to doing things the “correct” computer science way. “Eventual consistency” has been the standard that businesses have striven after since the Arab-Hindu cultures first invented dual-entry accounting, more than 500 years ago, and this is the standard that tech teams should enable for the businesses they serve.

Choosing to manage inconsistencies in this ...

March 24th, 2014

# What kind of standards are useful to your team?

I love this:

Its a bit of a diochotomy that microservice teams tend to eschew the kind of rigid enforced standards laid down by enterprise architecture groups but will happily use and even evangelise the use of open standards such as HTTP, ATOM and other microformats.

The key difference is how the standards are developed and how they are enforced. Standards managed by groups such as the IETF only become standards when there are several live implementations of them in the wider ...

March 24th, 2014

# The conceptual model of the world will differ between systems

Decentralization of data management presents in a number of different ways. At the most abstract level, it means that the conceptual model of the world will differ between systems. This is a common issue when integrating across a large enterprise, the sales view of a customer will differ from the support view. Some things that are called customers in the sales view may not appear at all in ...

March 23rd, 2014

# A complexity that is frankly breathtaking

How can anyone possibly think this is a good idea?

To quote James Lewis and Martin Fowler:

Certainly, many of the techniques in use in the microservice community have grown from the experiences of developers integrating services in large organisations. The Tolerant Reader pattern is an example of this. Efforts to use the web have contributed, using simple protocols is another approach derived from these experiences – a reaction away from central standards that have reached a complexity that is, frankly, ...

March 23rd, 2014

# The pushback against the monolithic framework

I am pleased to think that others are as ready as I am to abandon the concept of the monolithic framework:

Monolithic applications can be successful, but increasingly people are feeling frustrations with them – especially as more applications are being deployed to the cloud . Change cycles are tied together – a change made to a small part of the application, requires the entire monolith to be rebuilt and deployed. Over time it’s often hard to keep a good modular ...

March 23rd, 2014

# Leave the error checking in your code

I leave the asserts in my Clojure code. I see a similarity of spirit expressed in the sentiment of James Hague (I especially like the use of the word “reckless”):

That error checking is great during development was not controversial, but opinions after that were divided. One side believed it wasteful to keep all that byte and cycle eating around when you knew it wasn’t needed. The other group claimed you could never guarantee an absence of bugs, and wouldn’t ...

March 23rd, 2014

# A defense of MongoDB

I posted this on Hacker News and now re-post it here.

MongoDB offers the greatest benefit to those who have an evolving concept of their schema, and that tends to be startups, though I have worked in large firms that entirely re-invented their schemas. I worry that I would seem tedious if I listed the places that I have worked, and yet, on Hacker News, when I speak in abstract terms, I tend to get downvoted, so I will name a ...

March 21st, 2014

# Announcing Humorus-MG

I just released Humorus-MG. This is an admin CMS for managing a collection in MongoDB. The app is written in Clojure.

The README contains an unintentional mini-manifesto of what I believe about creating web software. This part in particular comes close to summarizing the kind of software that I would like to create this year:

—————-

1.) This app will never have more than 2,000 lines of Clojure code. None of my apps will ...

March 20th, 2014

# Why I use MongoDB

I posted this on HackerNews. I am in agreement with what Jun Xu wrote.

I think this is true:

“For a technology startup with limited resources, broadly adopting a new DBMS means betting its own future on the DBMS. ”

It has become popular to attack MongoDB, but I think it is difficult to get an objective view of what people are doing with it. If you want to read a really scathing attack on MongoDB, consider this post:

http://www.sarahmei.com/blog/2013/11/11/why-you-should-never-use-mongodb/

But I recall reading that ...

March 9th, 2014

# Criticker gives away all of its users passwords

Criticker gives away all of its users passwords in plain text. Of course the site is written in PHP. While you can make mistakes in any language, this kind of laziness is what you expect in PHP.

Every request contains the secret key in the url. So all I need to do is capture a single request sent by the app and I have the key. Easy.

My theory was that I’d get the list of users that the app had ...

March 8th, 2014

# Working with images using Clojure

I am intrigued by Mike Anderson’s “imagez” library:

Source

March 8th, 2014

# How to monitor Clojure apps?

Interesting:

Powerful stream primitives

(where (or (service #”^api”) (service #”^app”)) (where (tagged “exception”) (rollup 5 3600 (email “dev@foo.com”)) (else (changed-state (email “ops@foo.com”)))))

Riemann streams are just functions which accept an event. Events are just structs with some common fields like :host and :service You can use dozens of ...

March 8th, 2014

# How to bankrupt a successful software company

Interesting:

Quark 5 and OS9 was what we were used to, but it was pretty miserable. The things that stick out:

Restarting your computer and losing your unsaved work over software freezes was a regular part of your day. Like, many times a day. We had all these crazy workarounds to achieve certain effects like drop shadows or change-and-repeat. It was all pretty rudimentary and hard to standardize across many designers in a department. Shapes were pretty much a non-issue, so we had to ...

March 7th, 2014

# The downside of Unit Testing

Interesting:

I’m back in Java-land these days, which is culturally very pro-unit testing. After getting exposed to it again for a few months again I’ve come to side with the author here. I’ve never really been comfortable with the amount of time certain people dedicate to unit testing, especially the TDD crowd, but in my hiatus something has arisen in popularity which has made it all the worse: mockito. Prior to mockito, unit testing was (more or less) limited to testing that ...

March 4th, 2014

# Darren Holloway walks through the philosophy of Ring/Clojure

Darren Holloway has written a post that should be added to the wiki on Github where Ring is hosted. He covers all the stuff that had me the most confused when I started doing web development with Clojure. He offers easy examples in pseudo-code to get the basic ideas across. I wish every project on Github had an introductory tutorial written in this style.

An excerpt:

Ring Conceptually

Technically, Ring isn’t a framework or an application, but rather a specification ...

March 4th, 2014

# What it is like to think you are talented when you are ignorant

Despite the “worst practices” approach, the thing worked.

I like this story very much. My own story is a bit different, circa 2000-2005 I built a CMS out of PHP, and I did eventually find good ways to structure it, and I remain an opponent of “object oriented programming”. But other than that, a lot of this story overlaps my own.

Despite what I now refer to as my “worst practices” approach, the thing worked. Every bad tutorial, every anti-PHP ...

March 3rd, 2014

# Emotional intelligence and success with Bitcoin

Or rather, maladaptive ways to deal with stress:

After Mt. Gox was hacked for the first time in summer of 2011, a friend asked Powell to help out, and soon, the San Francisco entrepreneur found himself on a plane to Tokyo. After landing, he rushed to Shibuya station, where he was met by his friend, Roger Ver, one of the world’s biggest bitcoin supporters who just happened to live across the street from Mt. Gox. Without bothering to drop off ...

March 3rd, 2014

# The difference between database indexes and database histograms

Several things occurred to me when I read this, some of them off-topic, including my use of MongoDb, and how I have been unthinkingly re-creating histograms without even giving them that name. I do not regard that as a problem with MongoDb, it gives flexibility by doing very little itself, everyone using it is hopefully aware of the need to re-create database functionality within one’s own app.

Then I asked myself the question: how does Oracle estimate that there are ...

March 3rd, 2014

# I still don’t get PAAS

This is the problem for me:

In my ideal world, deploying my apps wouldn’t require any platform-specific code, or if it did, that code would be portable between platforms.

If I have to be aware of my servers, at all, then I’m still doing sysadmin, and if I have to do sysadmin, I want all the tools of sysadmin. I don’t want to do sysadmin on a crippled account that limits my options. Maybe someday there will be a real PAAS such ...

March 1st, 2014

# What is correct HTML syntax?

Matias Meno of Colorglare asks the question “TO CLOSE OR NOT TO CLOSE?”

This is from Ian Hickson in 2006, regarding the emergence of HTML5:

Regarding your original suggestion: based on the arguments presented by the various people taking part in this discussion, I’ve now updated the specification to allow “/” characters at the end of void elements.

To which Sam Ruby responded:

This is big. PHP’s nl2br function is now HTML5 compliant. WordPress won’t have to completely convert to HTML4 before people who ...

February 9th, 2014

# Bloated software promises a stability which might be a liability

Interesting:

IT organizations are facing accelerating pressure to support companies’ growing need for business agility, innovation, customer responsiveness, and adaptability. This pressure doesn’t stop with so-called systems of engagement. It goes all the way back to systems of record. In fact, the distinction between the two is starting to erode. Enterprises are responding to this pressure by upgrading application architectures within and around the system-of-record tier. They are starting to view the “stability” of their legacy applications as a liability rather ...

February 9th, 2014

# Drupal is bloated software

Stuff like Drupal offers ease of use for standard operations, and yet, when I work with clients, I find they have very few “standard” operations. Everything needs to be customized, and that is where Drupal becomes difficult:

Drupal, much like many other CMSs, follows a development methodology that I call reverse development. It is the simple idea that the most fundamental moving parts of the technology have been already built for you, or are modifiable using a trivial UI, and ...

February 9th, 2014

# What is a Spruce Goose software project?

I have worked on software that was just like this:

Now the Spruce Goose was trying to fly. People couldn’t take their eyes off it. Who could comprehend its size! Three hundred-foot wingspan, seven-story tail, 200 tons of plane with room for 700 soldiers. It upstaged even the ocean liners lounging nearby. There it was, $25 million worth of prototype seaplane, skating along toward take-off, engines cackling and fuming. Howard Hughes, America’s most publicized aviator, designed it, swore by it, ... Read More Source February 9th, 2014 No Comments # Getting useful info out of git logs Interesting: git churn It’s possible to get valuable insight from history of a project not only by viewing individual commits, but by analyzing sets of changes as a whole. For instance, git-churn is a simple but valuable script that wraps git log to compile stats about which files change the most. For example, to see where the development of an app was focused on in the past 6 months:$ git churn –since=’6 months ago’ app/ | tail Incidentally, such analysis also highlights ...

February 7th, 2014

# The most difficult thing about programming

Everything is working, then it breaks, and you never know why. The technologies we rely on are too numerous and complicated for us to understand them all — this is disempowering. I find this the most difficult thing about being a programmer: the surprise that even we can not understand all the technologies we use.

When I’d finished this article, I wanted to spell check the content. emacs-ispell mode decided to go on strike. It could not find aspell, the ...

February 5th, 2014

# Trying to use the Formative library

This is an interesting problem. I have records in a MongoDb database. Every record has a “created-at” field, stored as a datetime. This is a screenshot of the value:

When I load this value via into a form via Formative, all the values fill in except for the year. Check out the screenshot:

I wonder if this is a bug or if I have to reformat the datetime?

Source

February 5th, 2014

# Working with Clojure and Dire

Here is a puzzle. I had a function “fetch” in namespace “controller” and it calls a function in namespace “secretary”. The secretary stores documents away, and then later gets them back, or it might return nothing, if there is nothing to return. I have a query “paginate-items” which on some pages correctly returns nothing, because on some pages there is nothing to paginate. But this function has been giving me problems. I decided to split my “fetch” function into a ...

February 4th, 2014

# Git is complicated because there are 5 places content can go

Interesting:

Why do these Places Exist? These places are part of the power and flexibility of Git over other systems.

With an index, we can choose how to commit a multitude of changes, without having to commit to all our changes at once. This is a great flexibility. With the local repository versus the remote repository, we turn Git into a distributed version control system, where each repository is conceptually just as equal to the next one. With stash, ...

February 3rd, 2014

# Lisp as a mathematical formalism for recursive functions

Very interesting:

One of my favorite classes in school was 15-453: Formal Languages, Automata, and Computation, which used Sipser’s Introduction to the Theory of Computation:

One aspect that I really enjoyed was that there was a narrative; we started with Finite State Automata (FSA), analyzed the additional power of Pushdown Automata (PDA), and saw it culminate in Turing Machines (TM). Each of these models look very similar and have a natural connection: they are each just state machines with different types ...

January 28th, 2014

# Mistakes that startups make

This reminds of the change between Symfony 1.x and 2.0:

The first mistake was made about 3 years ago, when we started building a new product, LiveRebel. When making the choice of technology we decided on the new web application framework Play, which fitted most of our development requirements very very well. Of course 6 months later Play committers made a decision to completely break backwards-compatibility for Play 2. So we were stuck with a technology that had an uncertain ...

January 23rd, 2014

# Why PHP is obsolete

I was a huge fan of PHP back in the year 2000. I started using it right before the official release of 4.0 in April of that year. At that time, if you wanted to build a website, the main alternatives were C, Java, Perl and ASP. My criticism of those 4 were:

1.) C — too complicated for a fast changing website. Compiling an app took time, compiling was slower back then, there were fewer Open Source tools, and ...

January 23rd, 2014

# A language non-programmers praise while getting drinks at a bar

Interesting:

When out with friends recently, one of them mentioned how awesome Julia is. I was surprised to hear someone talk about it, even from another person in science. She turned and gushed about how awesome it was, how supportive the community was, even though she was “not really someone who likes programming.” And she liked it so much she was telling her friends about it at a bar!

If you make a programming language that people who don’t like programming love ...

January 20th, 2014

# No one reads anyone else’s code for fun

Interesting:

January 17th, 2014

# The argument against type hinting in Clojure

Intersting:

But it doesn’t hurt, does it? So one might think: “It doesn’t help, but it doesn’t hurt either, so I sprinkle hints all over the place to give myself some info on what this function returns.” And indeed this thinking is wrong. By now it should be clear that type hints are a low-level construct. Using them in the above mentioned way over specifies the types the functions take and return. You basically lock the code which could in theory be ...

January 17th, 2014

# Aliases for namespace qualified keywords in Clojure

Interesting:

However what happens if two libraries modify the same map? On the same key? Then we are in trouble, because one overwrites the other. To remedy this issue, Clojure provides (similar to Symbols) namespace-qualified keywords. Simply add a double-colon in front and the keyword will be qualified with the current namespace. user=> ::foo :user/foo Using the fully-qualified form, we can create keywords with an arbitrary namespace. user=> :my.company.division.project.module-a/keyword :my.company.division.project.module-a/keyword So we can communicate with a library using its own qualified keywords. The library can then ...

January 17th, 2014

# Why are forums so badly designed?

This is ugly. I wonder why, since the 90s, forums have always had such awful graphic design?

Source

January 14th, 2014

# The awful magic syntax of Scala

Interesting:

Magic Syntax Over the years I’ve found that the easiest programming languages to get started with are those with the ‘simplest’ syntax. Simplicity is a hard thing to define, but in this case it is not the same as flexible. It’s actually closer to regular, or limited with extension options. I’ve found Lisp, Ruby and HyperTalk to be great examples. I’ve found AppleScript and Perl to be terrible.

Scala is easily the worst I’ve seen. That punctuation-strewn build system I was forced ...

January 12th, 2014

# Your app is not real time if anything blocks

Interesting:

(My background: I work for Google, I did a real-time web prototype using the client libraries for GChat back in 2009 when real-time search was all the rage, my Noogler mentor at Google was the frontend tech lead for the eventual real-time search product we launched, and before Google I’d worked in financial software, where real-time responsiveness really is required.) I think that the folks currently building prototypes in Meteor dramatically underestimate the difficulty of scaling up real-time software to production-grade ...

January 11th, 2014

# Broken ad technology

See screenshot. I was served the same ad 3 times on 1 page. This has to be a broken ad technology, yes? This cannot be deliberate: that would be idiotic.

Source

January 8th, 2014

# Functional programs are much more readily appreciated as mathematical objects

Interesting:

I write to you because of a rumor of efforts to replace the introductory programming course of our undergraduate curriculum the functional programming language Haskell by the imperative language Java, and because I think that in this case the Budget Council has to take responsibility lest the decision be taken at the wrong level.

You see, it is no minor matter. Colleagues from outside the state (still!) often wonder how I can survive in a place like Austin, Texas, automatically assuming ...

January 6th, 2014

# Deploying Clojure to production

This is a very interesting architecture for Clojure:

And this is an interesting bit of deploy info:

#!/bin/bash

set -u # Treat unset variables as an error set -e # Exit immediately if a simple command exits with a non-zero status

APP_HOME=/var/www/rssminer cd $APP_HOME INDEX_PATH=/var/rssminer/index TMP_INDEX_PATH=/var/rssminer/index2 LOG_DIR=/var/log/rssminer sudo mkdir -p$LOG_DIR && sudo chown deploy $LOG_DIR PER_MONGTH=date +”%Y-%m” # year-month- SHARED=”${LOG_DIR}/${PER_MONGTH}” nohup java -server -Dsun.jnu.encoding=UTF-8 ... Read More Source January 5th, 2014 No Comments # What are the advantages of functional programming? On Hackers News someone asked if those of us working with Clojure missed Object Oriented programming (OO). I responded: Short answer: no. Longer answer: an argument can be made that OO is a proven failure, and that there exists 40 years of evidence that OO is a failure. I will start by talking about the general case, and then I will narrow my remarks to the web, since that is what you are asking about. The least charitable way to describe OO is this: ... Read More Source January 4th, 2014 No Comments # The end of the HTML/CSS guru I am actually surprised this lasted so long. I switched to CSS in 2000. But apparently what mattered was not the practitioners, but the browsers themselves: once they unified on standards, the need for specialists disappeared. The reason the Web Standards Movement mattered was that the browsers sucked. The stated goal of the Movement was to get browser makers on board with web standards such that all of our jobs as developers would be easier. What we may not have realized ... Read More Source January 3rd, 2014 No Comments # Where Google fails at search Martins Programming Blog says there is a post on Hacker News with the title “Why is Clojure so slow?” So I run this search on Hacker News: “Why is Clojure so slow” site:news.ycombinator.com I get 9 pages of results, and none of them point me to the article. Source January 2nd, 2014 No Comments # Why git won as a distributed version control system Interesting: The third problem was Bazaars stance on completely immutable history. Software developers aren’t historians or lawyers. A lot of users were keen to keep their history simple. They cared about tracking what changes had happened to their trunk and having that sequence of changes be legible, not really about the individual commits and mistakes that led up to the patch that landed on trunk. Git offered “rebase”, which basically reapplies local changes on top of the upstream tree. Git is ... Read More Source December 31st, 2013 No Comments # Kill processes running on a certain port This is clever: searchAndDestroy() { lsof -i TCP:$1 | grep LISTEN | awk ‘{print $2}’ | xargs kill -9 echo “Port”$1 “found and killed.” }

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December 29th, 2013

# How to listen for the delivery of a promise in Clojure

The problem:

add-watch was alpha in Clojure 1.2:

it is still alpha now, in Clojure 1.5:

I am curious what the plan is for add-watch?

I was just reading this:

http://nurkiewicz.blogspot.com/2013/03/promises-and-futures-in-clojure.html

and this struck me:

And here is where the greatest disappointment arrives: neither future nor promise in Clojure supports listening for completion/failure asynchronously. … As much as I love Clojure concurrency primitives like STM and agents, futures feel a bit underdeveloped. Lack of event-driven, asynchronous callbacks that are invoked whenever futures ...

December 29th, 2013

# The lack of future listeners in Clojure

Interesting:

Futures behave pretty much the same way in Clojure from user perspective – they are containers for a single value (of course it can be a map or list – but it should be immutable) and trying to dereference future before it is resolved blocks. Also just like promises, futures can only be resolved once and dereferencing resolved future has immediate effect. The difference between the two is semantic, not technical. Future represents background computation, typically in a thread ...

December 28th, 2013

# How to reload an app in the REPL with Clojure

I have been working with Clojure now for much of the last 18 months, so I am no longer a complete noob. But I was slow to get used to working at the REPL. Working with the REPL is taken for granted in the Clojure community, so much so it is tough to find step-by-step instructions for doing it. For me, a confusing issue for a long while was, if I wanted to get back into an app, what are ...

December 27th, 2013

# Clojure is concise

So now I have a working, multi-threaded CMS, written in Clojure, and it has less than 1400 lines of code. This is a beautiful language.

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December 25th, 2013

# Dependency Injection is more important than dependency injection frameworks

Interesting:

I was one of the earliest adopter of Spring in Norway. We developed a large system where we eventually had to start thinking about things like different mechanisms for reuse of XML configuration. Eventually, this evolved into the @Autowire and component-scan which took away the problem with huge configuration files, but in return reduced the ability to reason about the whole source code – instead isolating developers in a very small island in the application.

The applications tended to blossom in ...

December 25th, 2013

# The rise of the algorithm economy

Interesting:

They seem to agree on one thing: from a workaday perspective, math is essentially useless. Lisp programmers (we are told) should be thankful that mathematics was used to work out the Lambda Calculus, but today mathematics is more a form of personal enlightenment than a tool for getting anything done.

This view is mistaken. It has prevailed because it is possible to be a productive and well-compensated programmer — even a first-rate hacker — without any knowledge of science or ...

December 25th, 2013

# Why Scala should be outlawed

Wow:

/** * Join 22 futures. The returned future is complete when all * underlying futures complete. It fails immediately if any of them * do. */ def join[A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V](a: Future[A],b: Future[B],c: Future[C],d: Future[D],e: Future[E],f: Future[F],g: Future[G],h: Future[H],i: Future[I],j: Future[J],k: Future[K],l: Future[L],m: Future[M],n: Future[N],o: Future[O],p: Future[P],q: Future[Q],r: Future[R],s: Future[S],t: Future[T],u: Future[U],v: Future[V]): Future[(A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V)] = join(Seq(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v)) map { _ => (Await.result(a),Await.result(b),Await.result(c),Await.result(d),Await.result(e),Await.result(f),Await.result(g),Await.result(h),Await.result(i),Await.result(j),Await.result(k),Await.result(l),Await.result(m),Await.result(n),Await.result(o),Await.result(p),Await.result(q),Await.result(r),Await.result(s),Await.result(t),Await.result(u),Await.result(v)) }

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December 25th, 2013

# When programmers say “types” what do they mean?

Interesting:

What To Know Before Debating Type Systems I would be willing to place a bet that most computer programmers have, on multiple occasions, expressed an opinion about the desirability of certain kinds of type systems in programming languages. Contrary to popular conception, that’s a great thing! Programmers who care about their tools are the same programmers who care about their work, so I hope the debate rages on.

There are a few common misconceptions, though, that confuse these discussions. This article ...

December 25th, 2013

# Music is training for concurrent programming

I suspect music is the best training for concurrent programming. This is interesting:

Rich Hickey Q&A by Michael Fogus Best known as the inventor of Clojure, a Lisp that runs on the Java Virtual Machine and the first new member of the Lisp family to attract any widespread interest since Scheme and Common Lisp, Rich Hickey has been a software developer and consultant for two decades. Prior to starting work on Clojure, he made four attempts to combine Lisp with either Java or ...

December 25th, 2013

# What I learned from Clojure

Someone on Hacker News asked “Why use Functional Programming”. I wrote this in response:

I don’t have an answer for you, but for the last year I have been learning Clojure, and I have found it fascinating. I do not think this will satisfy you, but I would like to share some of the things that I find interesting about Clojure.

Lately I’ve been studying the source code of Aleph, a web server written by Zach Tellman. Zach is a very ...

December 24th, 2013

# This is why Rails sucks

50 minutes of Yehuda Katz talking about Rails. He says he wants to answer the accusation that there is too much bulk in Rails. He argues that much of that bulk is doing important stuff that you don’t know about, and that if they do their jobs intelligently, as designers of a framework, you should never have to think about all the cool stuff that the code is doing for you, but that you should be grateful that all that ...

December 21st, 2013

# How to organize namespaces in Clojure?

This is good:

You can think of namespaces as a tool to express something about your application. Here are some ideas to get you started:

Group functions into namespaces based on type of data they manipulate. For example, functions to manipulate customer data go in the “customer” namespace. This technique is familiar from object-oriented languages, but it has the same limitations: where do you put functions concerning relationships among two or more types? The OO answer would be to make a new ...

December 19th, 2013

# Contract programming in Clojure

I’ve been drifting toward a contract style in my Clojure code. Among other things I’m discovering along the way, I’ve been rethinking the need to be clear about arguments to function. This used to seem like the Right Way:

Then I added assert statements:

(defn- add-items-to-map-of-related-items [map-of-items seq-of-items-to-add] (timbre/spy :debug “map-of-items given to add-items-to-map-of-related-items : ” ...

December 17th, 2013

# The marriage of math and computers

Amazing:

On last Thursday at the Heidelberg Laureate Forum, Vladimir Voevodsky gave perhaps the most revolutionary scientific talk I’ve ever heard. I doubt if it generated much buzz among the young scientists in advance, though, because it had the inscrutable title “Univalent Foundations of Mathematics,” and the abstract contained sentences like this one: “Set-theoretic approach to foundations of mathematics work well until one starts to think about categories since categories cannot be properly considered as sets with structures due to ...

December 14th, 2013

# Can we avoid firewalls by re-using obsolete ports?

Port numbers under 1000 tend to be associated with essential network services, so these are the least likely ports to be restricted by firewalls, yes? I am looking through the list of unix network socket ports on Wikipedia.

I am intrigued by the number of lower port numbers that seem to be available because their original official use has gone obsolete.

For instance: http://en.wikipedia.org/wiki/Xerox_Network_Systems

had ports 52, 54 and 58. Current status:

“Last used by Xerox for communication with the DocuTech 135 Publishing System, ...

December 14th, 2013

# When will media companies understand technology?

The big media event today is Beyonce’s new video. So of course, the server is down? The error is a WordPress error. When do media people learn how to use software and servers to handle big spikes in traffic?

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December 13th, 2013

# The heyday of unix

Usually when something is at its peak its victory seems so natural that no one really appreciates it in the moment. It is worth noting that Microsoft lost momentum with developers at some point in the period 2000 – 2005, and this has lead to the heyday of Unix, mostly Linux. All of the competitors are dead. I am not sure what comes after Unix, but it is noteworthy how much it dominates the landscape for applications that do not ...

December 9th, 2013

# Find all field names in MongoDb

I am switching from PHP/Mysql to Clojure/MongoDb. In Clojure, hyphens in names are more idiomatic than underscores. So I wanted to find all the field names, so I could see where the underscores were. Having done a straight import of all of my database tables into a single MongoDb collection, I ran this Javascript at the Mongo shell to get all the field names.

var arrayOfFieldNames = [];

var items = db.tma.find();

while(items.hasNext()) { item = items.next(); for(var index in ...

December 4th, 2013

# How to work with Clojure’s EDN

This is a fantastic little write up about how to work with EDN:

The first place I started with EDN, was with the clojure.edn namespace, which has a very short API documentation and this was my first point of confusion. I could see a read and read-string method… but couldn’t see how I would actually write EDN? Coming from a background that was used to JSON, I expected there to be some sort of equivalent Clojure to-edn function lying ...

December 3rd, 2013

# Scala is horrible

I had to work with Scala for a few weeks at Timeout. I hated it. I notice that most programmers who have been exposed to Scala and Clojure will either prefer Scala or Clojure — I have not yet met anyone who liked them both. Scala or Clojure are extreme opposites. But why do programmers divide over this issue? I was leaning toward the idea that it had something to do with types, with some programmers liking algebraic types (and ...

December 3rd, 2013

# The difference between Scala and Clojure

Check out this matrix that shows which languages have projects that allow them to output code in another language. The difference between Scala and Clojure is extreme. Clojure has more targets than any other language, and Scala has none. Nobody uses Scala to produce some other code, whereas it is clearly a huge source of joy for Clojure programmers.

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November 30th, 2013

# What is bound-fn good for?

In Clojure, this is a great example of how and why to use bound-fn:

At work we have some tests that spin up various jetty instances that return sample test data. We use these to mock out other services on our platform and switch the app’s config at test time to point at them instead of the real services. It’s actually a pretty great set up that I plan to talk about at a later date but a specific issue ...

November 30th, 2013

# How to handle loops in bash

This is a great collection of bash tips:

1. for i in $(ls *.mp3) One of the most common mistakes BASH programmers make is to write a loop like this: for i in$(ls *.mp3); do # Wrong! some command $i # Wrong! done for i in$(ls) # Wrong! for i in ls ...

November 30th, 2013

# Church Numerals make all numbers the results of funtions

Lately I’ve been wondering a lot about where numbers come from. My research lead me to this interesting post about Church Numerals.

Assume we have a programming language that doesn’t support numbers or booleans: a lambda is the only value it provides. It is an interesting question whether we can nonetheless create some system that allows us to count, add, multiply, and do all the other things we do with numbers. Church numerals use lambdas to create a representation of numbers. The idea ...

November 24th, 2013

# A brilliant attack on object oriented programming

This is very good. I wish I had written it:

Jake’s on the job

Phil: Hey Jake. I’ve been looking at this class of yours. It’s a little bit too big.

Jake: Sorry. And what’s the issue with that?

Phil: Well, thing is. It’s got too many responsibilities. It does too much.

Jake: And?

Phil: Well think about it. If it does too much, it means that it touches many parts of the system. So the probability of having to touch the class when changing code ...

November 12th, 2013

# Pipe-and-filter architectures are among the most successful design patterns ever

This is the first time I have ever felt like I understood what Storm is for. I have tried to read about Storm, but every description I’ve read leaves me confused. Consider the official description from the Github page: “Distributed and fault-tolerant realtime computation: stream processing, continuous computation, distributed RPC”. Does that tell you anything? I am left confused. This instead make sense to me:

Pipe-and-filter architectures are among the most successful design patterns ever. They dominate data ingestion and processing ...

November 9th, 2013

# Small apps and specialized machines

This is a bit of speculation on my part. I wrote previously about using small apps to build big web sites. I want to re-emphasize the Big Ideas from that article:

1.) big apps eventually become expensive to maintain

2.) small apps are easy to maintain

3.) an architecture of small apps might leave you with a lot of apps, which need to be managed, but managing them becomes a management issue, rather than a technical issue. Technically, the app is easy ...

November 7th, 2013

# Michael Drogalis shows a very concise pipeline

Michael Drogalis has another one of those posts from which I learn a lot. In this case I am impressed that he manages to get the abstract concept of a pipeline down to the minimum of code:

(defn pipeline [] (let [bound 10000 m-ch (chan bound) n-ch (chan bound) o-ch (chan bound)] (go (while true ...

November 7th, 2013

# Object oriented artifacts in a functional world

I love this:

In the world of object-oriented programming, it is common to create classes to represent data elements from your domain. These classes run into all kinds of trouble. First, they tend to breed closely coupled classes like DTOs and XML type mappers. Second, they rarely contain any intelligence and sometimes don’t contain any behavior at all. Third, proliferating concrete classes can make it hard to see common abstractions trying to escape.

In the past, I answered all of those ...

October 16th, 2013

# lsof files of a particular user or process

I sort of knew that lsof was a useful command, but these are nice examples of how to see files in use by just a particular user or process:

6. List files opened by a specific user

In order to find the list of files opened by a specific users, use ‘-u’ option.

# lsof -u lakshmanan

COMMAND PID USER FD TYPE DEVICE SIZE/OFF ...

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