Use Ubuntu base image for main container

[felixvanoost]

Replaces the base Docker image for yuzutech/kroki (eclipse-temurin:11.0.17_8-jre-alpine) with the Ubuntu flavour of the latest JRE 11 image (eclipse-temurin:11.0.18_10-jre-jammy). This variant has both arm64 and amd64 variants available, which should resolve one of the last remaining roadblocks to adding native ARM support to Kroki.

The use of a Ubuntu base image may have some other secondary advantages as well, e.g. more widespread support during development/debugging.

Notes:

• I still need to quantify the final size difference between the Ubuntu and Alpine images.
• The latest version of graphviz available using apt (2.42.2) is behind the latest version available using apk (3.00.0), so there may be some unexpected consequences from this change.

[felixvanoost]

@ggrossetie I'm getting the following error related to canvas when trying to run Vega with PNG or PDF files. This also happens locally on my machine:

response: Error 500: Error: CanvasRenderer is missing a valid canvas or context

What's puzzling me is that kroki-builder-vega seems to be working fine; it passes all the dpkg tests. This leads me to believe that it's something related to how canvas is being brought into the main image. I noticed that it's currently being copied separately:

COPY --from=kroki-builder-vega /app/app.bin /usr/bin/vega
COPY --from=kroki-builder-vega /app/canvas.node /usr/bin/canvas.node

Do you know why this was done? I'm not really familiar with Node.js but it seems like the the Vega app.bin shouldn't need any external dependencies?

[ggrossetie]

Do you know why this was done? I'm not really familiar with Node.js but it seems like the the Vega app.bin shouldn't need any external dependencies?

As far as I remember, canvas is an external dependency. I don't recall exactly why but https://github.com/vercel/pkg cannot include it inside the vega binary, that's why we need it.

If you get an error Error: CanvasRenderer is missing a valid canvas or context, please install the canvas package (or install vega-cli).

From https://vega.github.io/vega-lite/usage/compile.html

[felixvanoost]

@ggrossetie I found a way to include the canvas package within the final binary executable generated by adding it as a pkg asset (see docs). This avoids the manual copy step and seems to fix the issue I was having. All the tests are passing locally on my machine now.

[ggrossetie]

@felixvanoost Nice! Let's see how it goes on the CI.

[felixvanoost]

This is ready to merge from my side. If approved, I'll use this as the starting point for creating an arm64 version of the main image in a separate PR.

[ggrossetie]

Thanks, I will take a closer look this week-end.

[ggrossetie]

LGTM, thanks again for your contribution 👌🏻