Go: x/build/cmd/coordinator: ssh proxy should support scp

Created on 24 Jul 2017 · 3Comments · Source: golang/go

As of https://golang.org/cl/50750 the build coordinator has an ssh server to proxy to buildlets. (That was bug #19956)

But there's no scp support yet.

This is a tracking bug to figure that out.

Builders FeatureRequest help wanted

Source

bradfitz

Most helpful comment

gomote put and gomote gettar are tedious and don't work with existing tools like rsync.

The normal ssh client isn't supported directly.

It is if you run it by hand. gomote ssh echos out the command you could run on your own.

All that's required to fix this bug (I think) is to respond to "sftp" channel open requests in our ssh server and open a new onward "sftp" channel to the backend and stitch them together with a copy io.Copy goroutines.

bradfitz on 16 Aug 2018

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/cc @dmitshur

bradfitz on 13 Aug 2018

This is one of the issues I'm looking at. In trying to envision how it would work, the following question came up.

Given that we have gomote put, is scp support going to be needed and helpful? Doesn't gomote put already do what scp would let you do? Or are there specific use cases we're aware of that would make this worthwhile.

One observation about ssh vs scp. Gomote currently lets the user "ssh into" a buildlet by running gomote ssh <instance>, but it works by creating an ssh shell and letting the user use it. The normal ssh client isn't supported directly. I don't think the same solution would work for scp, because we don't want to re-implement all the complex syntax that the scp client supports.