Daphne's dependencies

A gentle introduction to dependency-cruiser

Daphne is a software engineer. She works on a project where everything in a folder called sub (not her choice) got deprecated. So she adds rule to the .dependency-cruiser.json in the root of her project:

{
  "forbidden": [
    {
      "name": "sub-not-allowed",
      "severity": "error",
      "from": { "pathNot": "sub" },
      "to": { "path": "sub" }
    }
  ]
}

Dependencies from everywhere to the sub folder are verboten from now on. Except when they come from sub itself. :heart:.

dot

To get a feel of what she's in to, she runs a dep-cruise and runs the result through dot. (Daphne is like that. She and her command line: a terrifying weapon.)

dependency-cruise -v -T dot test/fixtures | dot -T png > sample-dot-output.png

err

Her Makefile already has dep-cruise target, which is run as part of the checks on her ci. (She also has a run script in her package.json, because her colleagues like that, but she prefers make herself - it's how she's wired)

Lo and behold - on the next push to her feature branch the build neatly fails. She loves how the exit code reflects the number of offending dependencies when she uses the err output type:

dependency-cruise -T err -v test/fixtures

  error sub-not-allowed: test/fixtures/cjs/root_one.js → test/fixtures/cjs/sub/dir.js
  error sub-not-allowed: test/fixtures/cjs/two_only_one.js → test/fixtures/cjs/sub/dir.js

✖ 2 violations (2 errors, 0 warnings)

make: *** [dependency-cruise] Error 2

(Daphne also loves how -T err just shuts up and stays out of her way if there's nothing wrong.)

So she gets on to refactor the code to obliterate those doubly blasted modules in sub.

html

In the mean Alex, who's an architect in Daphne's project, gets a whiff of what is afoot and heads over to the visual build output.

The build server knows its architect, so it put a dependency report in a spot where Alex can find it easily. This is the command:

dependency-cruise -v -T html -f stuff-for-alex/sample-dot-output.html test/fixtures

(Actually the build server didn't. You know that. Build servers aren't that nice. In fact that darn clever Daphne put it in her Makefile. Near her coverage reporting. The build server just ran it blindly.)

Alex gets a little cramp in her neck, just when she discovers the tiny little rotate button. That's better:

csv

Daphne and Alex are covered. Their micro-managing spreadsheet hugging senior environs, however, is not. Hence: comma separated values. In a file. So excel (or LibreOffice) can chug it like it's 1999:

dependency-cruise -v -T csv -f sample-dot-output.csv test/fixtures

json

This is there for the persona 'Marty the maintainer', so he can debug things.

dependency-cruise -T json -v -f sample-json-output.json test/fixtures

The result is rather voluminous, so here's just a link if you want to see it assets/sample-json-output.json.