tftp: make file filename mandatory and anchor the regex to the end of line too

[rgl]

I think the following regex should be modified to ^(.+)-[[:xdigit:]]{2}-([[:xdigit:]]{32})-([[:xdigit:]]{16})-([[:xdigit:]]{2})$:

https://github.com/tinkerbell/boots-ipxe/blob/e9e36bd85356785cfeaf9e2f340d5a751f5b1708/tftp/tftp.go#L123

I'm also curious, is there a reason for not using a query string alike syntax? for example, filename?traceparent=xxx?

[jacobweinstock]

Hey @rgl, thanks for the feedback. I'm curious about "make file filename mandatory". Would you mind expanding on this idea?

In regard to "anchor the regex to the end of line", what do you think we gain by capping the name in this way?

"is there a reason for not using a query string alike syntax?"
The reason is that this code was taken from the work already done to enable otel in Boots proper. https://github.com/tinkerbell/boots/blob/129caee6916a2ef9a5cb4af216141654b0bc6e77/cmd/boots/tftp.go#L120

[rgl]

Hey @rgl, thanks for the feedback. I'm curious about "make file filename mandatory". Would you mind expanding on this idea?

the regex .* means its optional, that is, it matches zero or more characters.

In regard to "anchor the regex to the end of line", what do you think we gain by capping the name in this way?

prevent it from being interpreted as something else? that way, the id would be always at the end of the string. not at the middle.

"is there a reason for not using a query string alike syntax?" The reason is that this code was taken from the work already done to enable otel in Boots proper. https://github.com/tinkerbell/boots/blob/129caee6916a2ef9a5cb4af216141654b0bc6e77/cmd/boots/tftp.go#L120

I'm not sure how picky the tftp clients are, but stashing an id in a filename using a regular char (-) is quite odd for me; I would prefer a more structured way (like a query string).