How to produce tikz diagram with HTML output?

[adamryczkowski]

I use Ubuntu 24.04 with
Asciidoctor 2.0.23 with asciidoctor-diagram and
Runtime Environment (ruby 3.2.3 (2024-01-18 revision 52bb2ac0a6) [x86_64-linux-gnu]) (lc:UTF-8 fs:UTF-8 in:UTF-8 ex:UTF-8)

I have also pdf2svg and TeXLive installed.

On my setup I can render asciidoctor-pdf tikz-demo.adoc -r asciidoctor-diagram -o tikz-demo.pdf where contents of tikz-demo.adoc are taken from https://docs.asciidoctor.org/diagram-extension/latest/diagram_types/tikz/.

How do I generate output for HTML (with SVG)?

asciidoctor tikz-demo.adoc -r asciidoctor-diagram -o tikz-demo.html

just inlines the tikz code into the html without executing it and does not return any error.

[pepijnve]

If you see the tikz code inlined then the image generation failed. You should get an error message on the console then. You could try adding on-error=abort as attribute to the tikz block. That should force asciidoctor to abort on error instead.
To get SVG output, you'll also have to add format=svg to the block.