../jekyll-to-zola

Migrating from Jekyll to Zola while preserving permalinks

Intro

I've been deploying this blog using Jekyll for quite a while now. This is the default choice for GitHub Pages, so why not. I've only been writing here occasionally from the same laptop, so it did not bother me too much. Until it did.

Jekyll is Ruby-based software. So you need to deal with Ruby. I tried wrapping it into nix, which I've been using at one of my jobs, but it was almost painfully slow. Also, I did not have any inspiration to write my custom themes and I did not find anything pretty for Jekyll. The default minima theme is honestly just hot garbage.

I tried Hugo, but it just didn't sit right with me. So, after doing some searching I settled with the combination of Zola with the Anemone theme. It is beatiful, it is fast, it does live reloads out of the box and Zola is just a single binary. No dependency hell, yay! And just a superior experience overall.

But the transition is not very straightforward. When you have a bunch of links you posted across the Internet, you want to keep them alive regardless of what software you use to generate your site. With the default settings (that I have been using, of course), Jekyll generates permalinks that look like this: /blog/<year>/<month>/<day>/<page-name>. Well, Zola doesn't do that. And doesn't plan to do that. Not a big issue for any future pages, I literally don't care. But old permalinks and the feed need to be preserved somehow. Oh, and the time format is incompatible too, since Zola sticks to RFC3339.

Ok, this is going to be an interesting evening and I need some beer. Let's get started...

The setup

Assuming you have done the initial setup with Zola and Anemone, let's create our blog page:

mkdir content/blog
cp themes/anemone/content/blog/_index.md content/blog

Now we have an empty blog. Next, let's copy the contents of our old Jekyll-based blog.

cp <path-to-jekyll-blog>/_posts/*.md content/blog

Now we have an empty blog that doesn't work. Awesome.

Timestamps

That's an easy one. Jekyll timestamps this form 2018-08-11 18:42:00 +0300 aren't RFC-compatible. But something like this is: 2018-08-11 18:42:00+03:00. This calls for a simple sed line:

sed -i -e 's/ +0300/+03:00/g' content/blog/**/*.md

If you have multiple timezones, just do that for these timezones as well. It can be done nicer, but for me it was only two timezones, so I can't be bothered.

Now we have the blog that works, but the permalinks are not the same and we need to fix that.

We have no choice but to make up for the lack of this capability in Zola by leveraging the directory structure. E.g. do something like this:

content
├── blog
│   ├── 2018
│   │   ├── 08
│   │   │   ├── 11
│   │   │   │   ├── 2018-08-11-tiny-docker-images.md

Yes, it's bad, but it works and these are old posts, so I am not going to touch most of them anyway.

I did the job with a simple Python script:

import os
import pathlib
import shutil

# front matter for intermittent _index.md files
FRONT_MATTER = """
---
render: false
transparent: true
redirect_to: "/blog/"
---
"""

BASE = "content/blog/"

files = os.listdir(BASE)

for file in files:
    # don't do anything for _index.md
    if file == "_index.md":
        continue
    # construct directory paths
    sections = file.split("-")[:3]
    pf = BASE + "/".join(sections)
    # create these dirs
    pathlib.Path(pf).mkdir(parents=True, exist_ok=True)
    # magical _index.md files
    for i in range(1, 4):
        p = BASE + "/".join(sections[:i]) + "/_index.md"
        with open(p, "w") as f:
            print(FRONT_MATTER, file=f)
    # move our post to the correct place
    shutil.move(BASE + file, pf + "/" + file)

This script creates the appropriate directory structure, places our article inside it and creates empty _index.md files in all subdirectories. They are not rendered, but are needed for Zola to see your directory structure correctly. Otherwise your posts are not going to be rendered. transparent: true makes it so that whatever theme you are using it sees the posts nested inside these directories.

Preserving feed.xml

If your Jekyll blog generated the RSS/Atom feed, you want to have it with Zola as well. Good news: Zola can do that. Bad news: out of the box you are limited to either atom.xml or rss.xml. That one is easy to solve, though. Just copy Zola's template to your templates directory and rename it:

wget https://raw.githubusercontent.com/getzola/zola/b965c89d12689d658a70f67f78d9de76b1a1cf48/components/templates/src/builtins/atom.xml
mv atom.xml feed.xml

Then add this to your config.toml:

generate_feed = true
feed_filename = "feed.xml"

Woohoo, you are set! Almost...

If you are using Anemone, this section is for you. If you don't, do check that all links in your templates are correct. I warned you.

Anyway, here are the patches to fix links in Anemone:

Just apply these patches and you are finally done.

Conclusion

While the proper transition was definitely not straightforward, I definitely enjoy my new setup. It looks nice and it's a pleasure to work with. Zola is a great software and it has a vibrant community with some pretty nice design, like the one you are looking at right now.