Is it possible to create files with template variable replacement?

[moltar]

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Self-hosted

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38

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github.com

What is your question?

I am trying to solve the problem explained in #24882 in a slightly different way.

I want to use postUpgradeTasks option with templates to create a file for changesets.

Initially, I was thinking to just do echo "template" > .changesets/foo.md, but then I realized that this would not work, as after template replacement, there might be characters that will not be escaped and fail to echo.

So, I am wondering, is there an option to create a new file, and pass it thru a templating engine?

Logs (if relevant)

Logs

Copy/paste the relevant log(s) here, between the starting and ending backticks

[rarkins]

postUpgradeTasks can run anything you like, including templating engines. But you would need to make sure that any engine you need is installed

[moltar]

I normally do not do it.

But given that the only option would be to run in postUpgradeTasks, it has to be a CLI then?

I envision something like:

"postUpgradeTasks": [
  "echo \"{{var}}\" > .changesets/changeset-foo.md"
]

But my understanding is that before executing the command, Renovate will replace the templated variables, so that before the command is ran, it will be:

"postUpgradeTasks": [
  "echo \"REPLACED VALUES HERE\" > .changesets/changeset-foo.md"
]

So my concern is that if REPLACED VALUES HERE contains any escape characters, the command will fail.

For example, imagine including the entire {{body}} (changelog content) there. I think it'd be a huge mess, and there's no way to escape it.

[rarkins]

I'm not sure there's any solution to the escaping characters problem here

[moltar]

One possible solution, which currently does not exist, but would be relatively straightforward to implement is a Handlebars helper to convert to Base64, similar to encodeURIComponent.

Which, in Node.js, is basically just a Buffer.from(value).toString('base64')

https://docs.renovatebot.com/templates/#additional-handlebars-helpers

Then:

echo "{{{base64 baseDir}}}" | base64 -d > foo.md

renovate/lib/util/template/index.ts

Lines 8 to 26 in 7d69fa9

	handlebars.registerHelper('encodeURIComponent', encodeURIComponent);
	handlebars.registerHelper('decodeURIComponent', decodeURIComponent);
	handlebars.registerHelper('stringToPrettyJSON', (input: string): string =>
	JSON.stringify(JSON.parse(input), null, 2),
	);
	handlebars.registerHelper('replace', (find, replace, context) =>
	(context ?? '').replace(regEx(find, 'g'), replace),
	);
	handlebars.registerHelper('lowercase', (str: string) => str?.toLowerCase());
	handlebars.registerHelper(
	'containsString',
	(str, subStr) => str?.includes(subStr),
	);
	handlebars.registerHelper('equals', (arg1, arg2) => arg1 === arg2);

[rarkins]

That sounds like a good idea - PR welcome for adding that helper

[moltar]

#26197