1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
<!doctype html><html lang=en-us><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"><link href="data:image/x-icon;base64,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" rel=icon type=image/x-icon><title>Re-Inventing Task Runner That I Actually Used Daily</title><meta name=description content="Couple of months ago I had this brilliant idea of re-inventing the wheel bymaking an alternative for make."><link rel=alternate type=application/rss+xml title="Mitja Felicijan's posts" href=https://mitjafelicijan.com/index.xml><link rel=alternate type=application/rss+xml title="Mitja Felicijan's notes" href=https://mitjafelicijan.com/notes.xml><style>body{padding:1rem;max-width:760px;background:#fff;font-family:times new roman,Times,serif;line-height:1.35rem}hr{margin-block-start:1.5rem}h1,h2,h3{line-height:initial}footer{margin-block-start:3rem}table{max-width:100%;border-collapse:separate;border-spacing:2px;border:1px solid #000;border-left:1px solid #999;border-top:1px solid #999}blockquote{font-style:italic}table thead{background:#eee}td,th{border:1px solid #000;padding:4px;border-right:1px solid #999;border-bottom:1px solid #999;text-align:left}pre{text-wrap:nowrap;overflow-x:auto;margin-block-start:1.5rem;margin-block-end:1.5rem;padding:.5rem 0;border-top:1px solid #000;border-bottom:1px solid #000}pre code{line-height:1.3em}pre,code,pre *,code *{font-family:monospace;font-size:initial!important}img,video,audio{max-width:100%}header{display:flex;flex-direction:row;gap:3rem}nav{display:flex;gap:.75rem}.pstatus-orange{background:gold}.pstatus-green{background:#9acd32}.pstatus-red{background:#cd5c5c}@media only screen and (max-width:600px){header{flex-direction:column;gap:1rem}a{word-wrap:break-word}}</style><header><nav class=main><a href=/>Home</a>
<a href=https://git.mitjafelicijan.com/ target=_blank>Git</a>
<a href=https://files.mitjafelicijan.com/ target=_blank>Files</a>
<a href=/mitjafelicijan.pgp.pub.txt target=_blank>PGP</a>
<a href=/curriculum-vitae.html>CV</a>
<a href=/index.xml target=_blank>RSS</a></nav></header><main><div><h1>Re-Inventing Task Runner That I Actually Used Daily</h1><p>May 31, 2023<div><p>Couple of months ago I had this brilliant idea of re-inventing the wheel by
making an alternative for make. And so I went. Boldly into the battle. And to my
big surprise my attempt resulted in not a completely useless piece of software.<p>My initial requirements were quite simple but soon grow into something more
ambitious. And looking back I should have stuck to the simple version. My
laziness was on my side this time though. Because I haven’t implemented some of
the features I now realise I really didn’t need them and they would bog the
whole program and make it be something it was never meant to be.<p>My basic requirements were following:<ul><li>Syntax should be a tiny bit inspired by Rake and Rakefiles.<li>Should borrow the overall feel of a unit test experience.<li>Using something like Python would be a bit of an overkill.<li>The program must be statically compiled, so it can run on same architecture
without libc, musl dependencies or things like that.<li>Install ruby for rake is a bit overkill and can not be done with certain
really lightweight distributions like Alpine Linux. This tool would be usable
on such lightweight systems for remote debugging.<li>I want to use it for more than just compiling things. I want to use it as an
entry-point into a project, and I want this to help me indirectly document the
project as well.<li>It should be an abstraction over bash shell or the default system shell.<ul><li>Each task essentially becomes its own shell instance.</ul><li>Must work on Linux and macOS systems.<li>By default, running <code>erd</code> list all the available tasks (when I use make, I
usually put a disclaimer that you should check Makefile to see all available
target).<li>Should support passing arguments when you run it from a shell.<li>Normal variable as the same as environmental variables. There is no
distinction. Every variable is also essentially an environment variable and
can be used by other programs.<li>State between tasks is not shared, and this makes this “pure” shell instances.<li>Should be single-threaded for the start and later expanded with <code>@spawn</code>
command.<li>Variables behave like macros and are preprocessed before evaluation.<li>Should support something like <code>assure</code> that would check if programs like C
compiler or Python (whatever the project requires) are installed on a machine.</ul><p>Quite a reasonable list of requirements. I do this things already in my
Makefiles or/and Bash scripts. But I would like to avoid repeating myself every
time I start working on something new.<p>So I started with the following syntax.<pre tabindex=0 style=background-color:#fff><code><span style=display:flex><span>@env on
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:green># Override the default shell.</span>
</span></span><span style=display:flex><span>@shell <span style=color:#a31515>/bin/</span>bash
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:green># Assure that program is installed.</span>
</span></span><span style=display:flex><span>@assure docker-compose pip python3
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:green># Load local dotenv files (these are then globally available).</span>
</span></span><span style=display:flex><span>@dotenv .env
</span></span><span style=display:flex><span>@dotenv .env.sample
</span></span><span style=display:flex><span>@dotenv some_other_file
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span><span style=color:green># This are local variables but still accessible in tasks.</span>
</span></span><span style=display:flex><span>@var HI = <span style=color:#a31515>"hey"</span>
</span></span><span style=display:flex><span>@var TOKEN = <span style=color:#a31515>"sometoken"</span>
</span></span><span style=display:flex><span>@var EMAIL = <span style=color:#a31515>"m@m.com"</span>
</span></span><span style=display:flex><span>@var PASSWORD = <span style=color:#a31515>"pass"</span>
</span></span><span style=display:flex><span>@var EDITOR = <span style=color:#a31515>"vim"</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>@task dev <span style=color:#a31515>"Test chars .:'}{]!//"</span> does
</span></span><span style=display:flex><span> echo <span style=color:#a31515>"..."</span> $HI
</span></span><span style=display:flex><span><span style=color:#00f>end</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>@task clean <span style=color:#a31515>"Cleans the obj files"</span> does
</span></span><span style=display:flex><span> rm .obj
</span></span><span style=display:flex><span><span style=color:#00f>end</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>@task greet <span style=color:#a31515>"Greets the user"</span> does
</span></span><span style=display:flex><span> echo <span style=color:#a31515>"Hi user $TOKEN or $WINDOWID $EMAIL"</span>
</span></span><span style=display:flex><span><span style=color:#00f>end</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>@task stack <span style=color:#a31515>"Starts Docker stack"</span> does
</span></span><span style=display:flex><span> docker-compose -f stack.yml up
</span></span><span style=display:flex><span><span style=color:#00f>end</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>@task todo <span style=color:#a31515>"Shows all todos in source files and count them"</span> does
</span></span><span style=display:flex><span> grep -ir <span style=color:#a31515>"TODO|FIXME"</span> . | wc -l
</span></span><span style=display:flex><span><span style=color:#00f>end</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>@task test1 <span style=color:#a31515>"For testing 1"</span> does
</span></span><span style=display:flex><span> unknown-command
</span></span><span style=display:flex><span> echo <span style=color:#a31515>"test1"</span>
</span></span><span style=display:flex><span> ls -lha
</span></span><span style=display:flex><span><span style=color:#00f>end</span>
</span></span><span style=display:flex><span>
</span></span><span style=display:flex><span>@task test2 <span style=color:#a31515>"For testing 2"</span> does
</span></span><span style=display:flex><span> echo <span style=color:#a31515>"test1"</span>
</span></span><span style=display:flex><span> ls -lha
</span></span><span style=display:flex><span> docker-compose -f samples/stack.yml up
</span></span><span style=display:flex><span><span style=color:#00f>end</span>
</span></span></code></pre><p>One thing that I really like about Errand. Yes, this is what it is called. And
it is available at <a href=https://git.mitjafelicijan.com/errand.git/about/>https://git.mitjafelicijan.com/errand.git/about/</a>. Moving
on. One thing that I really like is that a task is a persistent shell. By that I
mean, that the whole task, even if it contains multiple command in one shell.
In make each line in a target is that and you need to combine lines or add <code>\</code>
at the end of the line.<pre tabindex=0 style=background-color:#fff><code><span style=display:flex><span><span style=color:green># How you do this things in make.</span>
</span></span><span style=display:flex><span>target:
</span></span><span style=display:flex><span> source .venv/bin/activate <span style=color:#a31515>\
</span></span></span><span style=display:flex><span><span style=color:#a31515></span> python script.py
</span></span></code></pre><p>This solves this problem. Consider each task and what is being executed in that
task a shell that will only close when all the tasks are completed.<p>By self-documenting I mean that if you are in a directory with <code>Errandfile</code> in,
if you only type <code>erd</code> and press enter it should by default display all the
possible targets. In make i was doing this by having a first target be something
like <code>default</code> that echos the message “Check Makefile for all available target.”
Because all of the tasks in Errand require a message I use that to display let’s
call it table of contents.<p>Because I don’t use any external dependencies this whole thing can be statically
compiled. So that also checked one of the boxes.<p>It works on Linux and on a Mac so that’s also a bonus. I don’t believe this
would work on Windows machines because of the way that I use shell instances. By
you could use something like Windows Subsystem for Linux and run it in
there. That is a valid option.<p>To finish this essay off, how was it to use it in “real life”. I have to be
honest. Some of the missing features still bother me. <code>@dotenv</code> directive is
still missing and I need to implement this ASAP.<p>Another thing that needs to happen is support for streaming output. Currently
commands like <code>docker-compose</code> that runs in foreground mode is not compatible
with Errand. So commands that stream output are an issue. I need to revisit how
I initiate shell and how I read stdout and stderr. But that shouldn’t be a
problem.<p>I have been very satisfied with this thing. I am pleasantly surprised by how
useful it is. I really wanted to test this in the wild before I commit to it. I
have more abandoned project than Google and it’s bringing a massive shame to my
family at this point. So I wanted to be sure that this is even useful. And it
actually is. Quite surprised at myself.<p>I really need to package this now and write proper docs. And maybe rewrite
tokeniser. Its atrocious right now. Site to behold! But that is an issue for
another time.</div></div></main><footer><hr><div><h3>Want to comment or have something to add?</h3>You can write me an email at
<a href=mailto:m@mitjafelicijan.com>m@mitjafelicijan.com</a> or catch up
with me
<a href=https://telegram.me/mitjafelicijan target=_blank>on Telegram</a>.</div><hr><p>This website does not track you. Content is made available under
the <a href=https://creativecommons.org/licenses/by/4.0/ target=_blank rel=noreferrer>CC BY 4.0 license</a> unless specified
otherwise. Blog feed is available as <a href=/index.xml target=_blank>RSS feed</a>.</footer><script src=https://cdn.usefathom.com/script.js data-site=XHQARKXP defer></script>
|
