Set mermaid configuration

[GuillaumeDesforges]

Mermaid has a bunch of features that need to be set at configuration level, such as mainBranchName for gitGraph.

Would it be possible to change mermaid configuration in a HTTP call?

[ggrossetie]

Hello Guillaume,

Technically, that's possible now that we accept a list of options and propagate them to the companion containers.
However, the Mermaid companion server does not retrieve the query parameters but it's possible to do so in:

kroki/mermaid/src/index.js

Lines 11 to 36 in 5023863

	const server = micro(async (req, res) => {
	// TODO: add a /_status route (return mermaid version)
	// TODO: read the diagram source as plain text
	const outputType = req.url.match(/\/(png|svg)$/)?.[1]
	if (outputType) {
	const diagramSource = await micro.text(req, { limit: '1mb', encoding: 'utf8' })
	if (diagramSource) {
	try {
	const isPng = outputType === 'png'
	const output = await worker.convert(new Task(diagramSource, isPng))
	res.setHeader('Content-Type', isPng ? 'image/png' : 'image/svg+xml')
	return micro.send(res, 200, output)
	} catch (e) {
	if (e instanceof SyntaxError) {
	return micro.send(res, 400, e.message)
	} else {
	console.log('Exception during convert', e)
	return micro.send(res, 500, 'An error occurred while converting the diagram')
	}
	}
	}
	return micro.send(res, 400, 'Body must not be empty.')
	}
	return micro.send(res, 400, 'Available endpoints are /svg and /png.')
	})
	server.listen(8002)

Then, we will need to update the Mermaid default config:

kroki/mermaid/src/task.js

Lines 5 to 32 in 5023863

	this.mermaidConfig = {
	theme: 'default',
	class: {
	useMaxWidth: false
	},
	er: {
	useMaxWidth: false
	},
	flowchart: {
	useMaxWidth: false
	},
	gantt: {
	useMaxWidth: false
	},
	git: {
	useMaxWidth: false
	},
	journey: {
	useMaxWidth: false
	},
	sequence: {
	useMaxWidth: false
	},
	state: {
	useMaxWidth: false
	}
	}
	}

Do you want to give it a try?

[GuillaumeDesforges]

Thanks, looks feasible.

I don't have the bandwidth to do it right now, so if anyone reading this wants it they should not rely on me implementing it.

[jhogendorn]

interested in this but from a different perspective, i'd like to be able to set kroki to have a default set of options for a given engine, or perhaps even a given referrer? ie, if wiki.mydomain.com calls a kroki diagram up, it can go 'oh, yep, the theme for that is this'.

[SayakMukhopadhyay]

Hi, I am a backstage user and I have the same requirement. I will make an attempt to implement this. Just one thing I need help on @Mogztter . How do I run the kroki-server locally, without using Docker and stuff. Preferably, is there a maven command that starts up kroki with a built in server like say spring-boot does?

EDIT:
Wait... do I just run main??? Seems like so...

[SayakMukhopadhyay]

I have created a PR which partially fulfills this issue. For now, it will pretty much work with only theme option for mermaid. Ngl, theme is what I personally need but I am also confused as to how to implement the other configuration params so haven't really worked on them. Let me know what you folks think.

[ggrossetie]

EDIT: Wait... do I just run main??? Seems like so...

Yes, the "gateway" server is a Vert.x stateless web app. You can indeed run the main 😉

I will make an attempt to implement this.

Thanks for contributing!

I have created a PR which partially fulfills this issue. For now, it will pretty much work with only theme option for mermaid. Ngl, theme is what I personally need but I am also confused as to how to implement the other configuration params so haven't really worked on them. Let me know what you folks think.

I will have a look this week-end 👍🏻