add post on drone-hugo

content/posts/2020-03-11-drone-hugo-plugin-that-works.md

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+date = "2020-03-11"
+title = "A Drone Hugo plugin that works"
+tags = ["drone", "hugo", "docker"]
+description = "building and publishing your static website with CI is awesome - when it works"
++++
+
+_This article contains some background to why I wrote this plugin. If you just want to use it, 
+see [github.com/ariejan/drone-hugo][github] for details._
+
+---
+
+I recently moved away from [Gitlab + Gitlab CI][gitlab] to a [Gitea][gitea] + [Drone][drone] setup.
+Both Gitea and Drone are lightweight and fast, and let's be honest, more than enough for 
+an engineering enthusiast like myself. They now also run on my ~~NAS~~ [Homelab Server][freenas] as docker
+containers, which helps to save a few bucks every month in hosting fees.
+
+## Hugo
+
+This website (and a few others I manage) are built using the static site generator named [Hugo][hugo]. It's
+written in Go andis super fast:
+
+```
+ ~/src/devroom.io $ hugo
+
+                   |  EN   
+-------------------+-------
+  Pages            | 1209  
+  Paginator pages  |    0  
+  Non-page files   |   13  
+  Static files     |  249  
+  Processed images |    0  
+  Aliases          |  450  
+  Sitemaps         |    1  
+  Cleaned          |    0  
+
+Total in 3073 ms
+```
+
+Because I like using `.scss` and some other goodies, I need to use `hugo_extended`. 
+
+## Drone + Hugo
+
+There's an official Hugo plugin for drone, but it has two problems:
+
+ * The official documentation is lacking on the use of the _extended_ version of hugo
+ * When you manage to get the extended version installed, it doesn't work
+
+As a good open source citizen, I opened up [the code][drone-hugo-plugin] and took a look around.
+At this point I noticed a few more "problems" with this plugin. 
+
+ * The plugin needs to run on multiple architectures\
+ * It contains a custom Go program to kick-off hugo builds
+ * It supports a metric ton of command line options for Hugo
+ 
+ ## Can I do better?
+
+ I could have taken up the official plugin and try to make it work. The problem here is that it's a 
+ rather complicated piece of software for a rather simple task:
+
+  1. Download the specified versio of Hugo
+  2. Run `hugo` to generate static HTML files
+
+What I found is that a Drone plugin can be written in whatever. Settings from `.drone.yml` are passed
+on as environment variables with a `PLUGIN_` prefix. 
+
+So, I opened up Vim and started to write a simple shell script that would download the proper,
+extended version of hugo and run it. This is all there is to it:
+
+```sh
+#!/bin/sh
+HUGO_VERSION=${PLUGIN_HUGO_VERSION:-"0.67.0"}
+HUGO_ARCH="64bit"
+
+HUGO_URL="https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_extended_${HUGO_VERSION}_Linux-${HUGO_ARCH}.tar.gz"
+
+echo "Fetching Hugo ${HUGO_VERSION} from ${HUGO_URL}"
+wget -q -O- ${HUGO_URL} | tar xz -C /usr/local/bin
+
+hugo
+```
+
+This will take the specified Hugo version (or default 0.67.0), download and untar it and run it. That's all I need.
+
+It does need to be packaged up in a Docker image to be useful with Drone, so I needed a `Dockerfile` as well.
+
+```Dockerfile
+FROM alpine:3.11
+
+RUN apk add --no-cache \
+    ca-certificates \
+    mailcap \
+    git \
+    wget \
+    libc6-compat \
+    libstdc++
+
+ADD drone-hugo.sh /bin/
+RUN chmod +x /bin/drone-hugo.sh
+
+ENTRYPOINT /bin/drone-hugo.sh
+```
+
+Again, this is pretty straighforward. Use alpine for a small image size, add some dependencies and copy over the shell script.
+
+## Using ariejan/drone-hugo
+
+In your `.drone.yml` you can add a `build` step. You'll want to follow that up with something that uploads your HTML files. 
+
+```yaml
+steps:
+  - name: build
+    image: ariejan/drone-hugo
+    settings:
+      hugo_version: 0.65.3
+```
+
+At this time there's no option to pass along any arguments to Hugo - as I don't need that. Instead of exposing each option
+manually, I'm considering to add a single `hugo_args` for that purpose. 
+
+You can find the full source and install instructions on [github.com/ariejan/drone-hugo][github].
+
+[gitlab]: https://about.gitlab.com/
+[gitea]: https://gitea.com/
+[drone]: https://drone.io/
+[freenas]: /2020/02/28/building-a-diy-home-server-with-freenas/
+[hugo]: https://gohugo.io
+[drone-hugo-plugin]: https://github.com/drone-plugins/drone-hugo
+[github]: https://github.com/ariejan/drone-hugo