add "pipelines considered harmful" post
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4 changed files with 209 additions and 30 deletions
18
Gemfile
18
Gemfile
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@ -1,10 +1,15 @@
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source "https://rubygems.org"
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gem "jekyll", "~> 4.2.0"
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gem "webrick", "~> 1.7"
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gem "jekyll", "~> 4.2"
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group :jekyll_plugins do
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gem "jekyll-feed", "~> 0.12"
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gem "jekyll-seo-tag", "~> 2.7"
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gem "jekyll-seo-tag", "~> 2.8"
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end
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require "rbconfig"
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if RbConfig::CONFIG["target_os"] =~ /(?i-mx:bsd|dragonfly)/
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gem "rb-kqueue", ">= 0.2"
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end
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platforms :mingw, :x64_mingw, :mswin, :jruby do
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@ -12,9 +17,6 @@ platforms :mingw, :x64_mingw, :mswin, :jruby do
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gem "tzinfo-data"
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end
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gem "wdm", "~> 0.1.1", :platforms => [:mingw, :x64_mingw, :mswin]
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require 'rbconfig'
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if RbConfig::CONFIG['target_os'] =~ /(?i-mx:bsd|dragonfly)/
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gem 'rb-kqueue', '>= 0.2'
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platforms :mingw, :x64_mingw, :mswin do
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gem "wdm", "~> 0.1.1"
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end
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39
Gemfile.lock
39
Gemfile.lock
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@ -1,20 +1,20 @@
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GEM
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remote: https://rubygems.org/
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specs:
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addressable (2.8.0)
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public_suffix (>= 2.0.2, < 5.0)
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addressable (2.8.1)
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public_suffix (>= 2.0.2, < 6.0)
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colorator (1.1.0)
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concurrent-ruby (1.1.9)
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concurrent-ruby (1.1.10)
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em-websocket (0.5.3)
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eventmachine (>= 0.12.9)
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http_parser.rb (~> 0)
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eventmachine (1.2.7)
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ffi (1.15.4)
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ffi (1.15.5)
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forwardable-extended (2.6.0)
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http_parser.rb (0.8.0)
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i18n (1.8.11)
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i18n (1.12.0)
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concurrent-ruby (~> 1.0)
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jekyll (4.2.1)
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jekyll (4.2.2)
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addressable (~> 2.4)
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colorator (~> 1.0)
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em-websocket (~> 0.5)
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@ -29,52 +29,53 @@ GEM
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rouge (~> 3.0)
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safe_yaml (~> 1.0)
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terminal-table (~> 2.0)
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jekyll-feed (0.15.1)
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jekyll-feed (0.16.0)
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jekyll (>= 3.7, < 5.0)
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jekyll-sass-converter (2.1.0)
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jekyll-sass-converter (2.2.0)
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sassc (> 2.0.1, < 3.0)
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jekyll-seo-tag (2.7.1)
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jekyll-seo-tag (2.8.0)
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jekyll (>= 3.8, < 5.0)
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jekyll-watch (2.2.1)
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listen (~> 3.0)
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kramdown (2.3.1)
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kramdown (2.4.0)
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rexml
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kramdown-parser-gfm (1.1.0)
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kramdown (~> 2.0)
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liquid (4.0.3)
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listen (3.7.0)
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listen (3.7.1)
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rb-fsevent (~> 0.10, >= 0.10.3)
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rb-inotify (~> 0.9, >= 0.9.10)
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mercenary (0.4.0)
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pathutil (0.16.2)
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forwardable-extended (~> 2.6)
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public_suffix (4.0.6)
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rb-fsevent (0.11.0)
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public_suffix (5.0.0)
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rb-fsevent (0.11.1)
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rb-inotify (0.10.1)
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ffi (~> 1.0)
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rb-kqueue (0.2.7)
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rb-kqueue (0.2.8)
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ffi (>= 0.5.0)
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rexml (3.2.5)
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rouge (3.26.1)
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rouge (3.30.0)
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safe_yaml (1.0.5)
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sassc (2.4.0)
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ffi (~> 1.9)
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terminal-table (2.0.0)
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unicode-display_width (~> 1.1, >= 1.1.1)
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unicode-display_width (1.8.0)
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webrick (1.7.0)
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PLATFORMS
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amd64-freebsd-12
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amd64-freebsd-13
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DEPENDENCIES
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jekyll (~> 4.2.0)
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jekyll (~> 4.2)
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jekyll-feed (~> 0.12)
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jekyll-seo-tag (~> 2.7)
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jekyll-seo-tag (~> 2.8)
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rb-kqueue (>= 0.2)
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tzinfo (~> 1.2)
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tzinfo-data
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wdm (~> 0.1.1)
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webrick (~> 1.7)
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BUNDLED WITH
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2.2.27
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2.3.21
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10
_config.yml
10
_config.yml
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@ -2,16 +2,20 @@ title: fef's blog
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description: Shitposts about tech, gender, and the Big Sad.
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baseurl: "/"
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url: "https://fef.moe"
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hs_url: "http://pv3gsakv2vlbknfnet7nkn532zzejowdxwrxajnrtasadwnitsgpawyd.onion"
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plugins:
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- jekyll-seo-tag
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mirrors:
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tor: "http://pv3gsakv2vlbknfnet7nkn532zzejowdxwrxajnrtasadwnitsgpawyd.onion"
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dn42: "https://fef.dn42"
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author:
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name: anna
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email: owo -at- fef.moe
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email: owo -at- fef . moe
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pgp:
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fingerprint: "9D39A75A5CDA0A5DAE78F92EEC22E476DC2D3D84"
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url: "/pgp.txt"
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fedi:
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user: fef
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host: notbird.site
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host: catcatnya.com
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twitter: libfef
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matrix:
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user: fef
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172
_posts/2023-02-21-pipelines-considered-harmful.md
Normal file
172
_posts/2023-02-21-pipelines-considered-harmful.md
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@ -0,0 +1,172 @@
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---
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layout: post
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title: "Pipelines Considered Harmful"
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tags: tech
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---
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Today, we're gonna have a closer look at pipes and what i consider "harmful" about them.
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Because i just *love* spicy takes that make a certain group of people with unreasonably strong
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opinions about computers really angry.
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UNIX pipelines, or just pipes for short, have been around for over half a century.
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The fact alone that they still see widespread use today is a manifestation of the genius behind their idea.
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However, they have some limitations that we apparently just accepted to have to live with.
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## What Is A Pipe?
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Before we dive in, though, let's briefly go over what pipelines are and what makes them so useful,
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just to make sure we're all on the same page.
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I know that you know what a pipe is, but i promise the following paragraphs are relevant to my point.
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Pipelines are an IPC mechanism that (at least in this form) first appeared in the UNIX operating system.
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They consist of a chain of multiple processes, where the standard output of the first one feeds
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into the standard input of the next one, and so on.
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In conjunction with the basic UNIX shell tools like
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[`grep(1)`](https://man.freebsd.org/cgi/man.cgi?query=grep&manpath=FreeBSD+13.1-RELEASE)
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or
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[`sort(1)`](https://man.freebsd.org/cgi/man.cgi?query=sort&manpath=FreeBSD+13.1-RELEASE),
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and even powerful stream processors like
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[`awk(1)`](https://man.freebsd.org/cgi/man.cgi?query=awk&manpath=FreeBSD+13.1-RELEASE),
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they enable composing sophisticated scripts within just a single line.
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This embracing of modularity over monolithic designs is a core aspect of the
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[UNIX philosophy](https://en.wikipedia.org/wiki/Unix_philosophy).
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And it makes perfect sense from the perspective of a programmer like
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[Douglas McIlroy](https://en.wikipedia.org/wiki/Doug_McIlroy)
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(the dude who came up with pipes) because programming just so happens to be all about
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abstraction and keeping things modular.
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## Plaintext Is Simple, Stupid
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An interesting aspect of UNIX command-line tools is that they operate predominantly on plaintext.
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And this is no coincidence.
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[Peter H. Salus](https://en.wikipedia.org/wiki/Peter_H._Salus)
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summarized Ilroy's documentation of the UNIX philosophy as follows:
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- Make programs that do one thing and do it well.
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- Write programs to work together.
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- Write programs to handle text streams, because that is a universal interface.
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What i'm obviously referring to is the third point, the one about plaintext.
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And i'm not saying it's wrong, but i want you to take a moment to think about this.
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At the time, the most complicated data you probably ever had to deal with was the output of `ls -l`.
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What's more, the vastness of different kinds of data has exploded since then.
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To give a practical example of where i'm headed, i have a small script that runs whenever i open up
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a new shell.
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It fetches my
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[canary message](https://fef.moe/canary.txt)
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using
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[`curl(1)`](https://man.freebsd.org/cgi/man.cgi?query=curl&manpath=FreeBSD+13.1-RELEASE+and+Ports),
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and extracts its `last-modified` HTTP header.
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It then compares this header with the current time and, if it is more than six days in the past,
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prints a message to the standard output reminding me to update the canary.
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Sounds simple, right?
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I must admit there is probably a more elegant solution, but the entire point of pipelines is to
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*avoid* having to spend too much time with such seemingly simple tasks.
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Also, the version below is somewhat simplified to make it easier to read;
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my original version is a true one-liner.
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Anyway, here goes:
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```sh
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SIX_DAYS=518400
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CANARY_DATE=`curl -I https://fef.moe/canary.txt |
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grep -i last-modified |
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cut -c 16-` # cut off the "last-modified: " part
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[ $(echo `date +%s` - `date -d "$CANARY_DATE" +%s` | bc) -ge $SIX_DAYS ] &&
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echo "update your canary ffs"
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```
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This works.
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However, i believe it is unnecessarily complex.
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It is the year 2023, and for some reason we still use the same shells as in the 1970s.
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Sure, zsh makes your life way easier, but no matter what you use,
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you're still limited to piping text from one program to another.
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Yes, HTTP response headers *can* be represented as plaintext; here is the output from the `curl`
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command in the example above:
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```
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$ curl -I https://fef.moe/canary.txt
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HTTP/2 200
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server: nginx/1.22.1
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date: Tue, 21 Feb 2023 15:11:30 GMT
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content-type: text/plain; charset=utf-8
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content-length: 3347
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last-modified: Tue, 21 Feb 2023 01:35:24 GMT
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vary: Accept-Encoding
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(remaining headers omitted for brevity)
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```
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## The goto Of Data
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But do we *have* to do it like that?
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The thing that makes pipelines "harmful" to me is that plaintext is just too dynamic.
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It could be *anything*.
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Parsing is a wildly complex problem of computer science,
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so why would we do that if there was an easier way?
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In his original article, Dijkstra considered the `goto` statement harmful because it lacks
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the clear structure of an `if` statement.
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This might be a little far-fetched, but you could view plaintext as the "goto of data".
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## Getting Spicy
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Computers have become powerful enough that performance pretty much isn't an issue for
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command-line tools anymore.
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Except for `dnf`; that one is just horrible.
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Microsoft have been exploring other ways of piping data from one program to another:
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[objects](https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_objects?view=powershell-7.3).
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Now, i don't really like PowerShell because it has several other poor design decisions,
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and the fact that it is a Microsoft invention is generally a gigantic red flag.
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However, i do believe that we could learn something from it.
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Why can't my shell script look something like this:
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```
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SIX_DAYS=518400
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CANARY_DATE=`curl -I https://fef.moe/canary.txt`.headers['last-modified']
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[ $(echo `date +%s` - `date -d "$CANARY_DATE" +%s` | bc) -ge $SIX_DAYS ] &&
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echo "update your canary ffs"
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```
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I'm not saying this syntax is good, what i care about is the idea.
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That program output *can* have a machine-readable structure, kind of like a JSON object.
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If someone were to design a specification for UNIX objects
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**and included a way to transform these objects back into plaintext for backwards compatibility**,
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i believe we would have a much easier time dealing with computers.
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Basically, something like this:
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```c
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struct attribute {
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char *name;
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char *value;
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};
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struct object {
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struct attribute *attributes;
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char *(*to_string)(struct object *);
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};
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```
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The `to_string` method would simply transform the object into the old-school textual representation.
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An actual implementation would of course have to deal with nested attributes and so on,
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but again, this is about the basic idea and not the details.
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## Computer Science Is A Process
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Don't get me wrong.
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As i clearly stated at the beginning of this article, i find the idea of pipelines as they exist
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today nothing short of ingenious.
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However, the field of programming is for some reason incredibly conservative.
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Why wouldn't we challenge ideas of the past, even if they work well for *most* use-cases?
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All that this "if it ain't broke, don't fix it" mentality has given us is an inability to spot
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shortcomings and limitations of existing technology.
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And that is, in my IMO, just sad.
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I'm not saying we should throw away everything.
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Just that maybe we should reevaluate our design decisions a little more often,
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and not be afraid of trying wild new concepts.
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