Write value to file

[theoephraim]

Often as part of our secrets / config, we encounter certificates or other things that are usually stored in files. Especially if they are large, passing things around through env vars doesn't really make sense. So we want a way to use varlock to fetch the value and write it to a file. The overall goal would be to make this work for any plugin, and to probably keep the "fetch the value" part within an item value, rather than a decorator.

A few options / ideas:

Option 1 - new file data type

Add a new data type called file which is meant to save the contents of the item to a path, and then return the file path as the env var. Conceptually it's a little weirder but is relatively simple.

# @type=file(./certs/my-cert.crt)
MY_CERT=op("op://...")

Option 2 - writeFile resolver which returns the path

Keep the value more related to being a file path, but have the data written as a side effect of a function. (Note that path is not a real type yet, but one that is planned on being added anyway).

# @type=path
MY_CERT_PATH=writeFile(./certs/my-cert.crt, op("op://...")) # writes the file and returns the path

Option 3 - writeFile resolver which returns the file contents

Break it up into 2 items, and have a writeFile function that writes the file but returns the value rather than the path.
In this case we may want another decorator to mark items that should not be injected as env vars (or could maybe use a naming convention). This one allows for validating both the path and the file contents independently, and is perhaps the most clear, but it's also a bit verbose.

We should also consider that often we wouldn't really need to inject the path as an env var because it is going to a known constant location, so you may not always need both items.

# @type=path
MY_CERT_PATH=./certs/my-cert.crt
# @type=crt @noEnvVar
MY_CERT_VALUE=writeFile($MY_CERT_PATH, op("op://..."))