[WIP] Allow ssh key override

[aelsabbahy]

Implement the "easy" solution requested in #86.

This adds two features:

• Allow the user to override ssh-key on a per network basis in Supfile
• Allow the user to override the ssh-key on the command line by using the -i flag

[VojtechVitek]

@aelsabbahy well done, this is a very good contribution! Thank you. Just a couple of naming nits and we can merge this..

[VojtechVitek]

They call it identity_file in ssh command. I'm thinking if we should be consistent with them.

[aelsabbahy]

Want it just changed in the docs or do you want the variable to also be renamed in the code?

Also, I take it networks: section should also have it renamed as identity-file?

[VojtechVitek]

We're trying to avoid dashes and underscores in the Supfile API. Can we think of one word here?

identity ... or sshkey ... any other suggestions?

[aelsabbahy]

IdentityFile is more verbose, but would match 1-1 with ~/.ssh/config syntax, thoughts?

[VojtechVitek]

+1

[aelsabbahy]

Sorry for the delay on my end.. been pretty busy and going on vacation.. I'll pick this back up in a few weeks.

[VojtechVitek]

@aelsabbahy no worries, thanks a lot!

[VojtechVitek]

Anyone wants to finish this PR based on the above comments?

btw: Related PR: #123

[kadefor]

@VojtechVitek Could I send a new PR to finish it (based on the PR and above comments)?

Currently, I want to add some features (#128):

• parse some host info (from Networks-Host string) using net/url, the string like this:
  ssh://username:password@hostname:port//path/to/ssh/key?KEY=value&KEY=value

  eg: ssh://tom:123@456@192.168.16.10:22//home/tom/.ssh/abc.key?MYSQL_HOST=127.0.0.1&MYSQL_PORT=3306

  we can get some info from it:

  1. ssh username: tom
  2. ssh password: 123@456
  3. ssh host: 192.168.16.10
  4. ssh port: 22
  5. ssh host+port: 192.168.16.10:22
  6. ssh identity file: /home/tom/.ssh/abc.key or ~/.ssh/abc.key
  7. some shell variables(per host per host env vars #111): MYSQL_HOST=127.0.0.1 and MYSQL_PORT=3306

  we can add a flag like --use-unsecure-password to enable the password feature

• update the package golang.org/x/crypto/ssh

• (Maybe) use flag -i to set (or add?) identity file

Could you give some advice? thank you!

[VojtechVitek]

@kadefor would be great if you could split it into separate PRs :) Thanks!

[mfridman]

@kadefor Just a heads up if considering updating the /x/crypto/ssh package.

In 2017 the Go team made a breaking change to ssh.ClientConfig. (tl;dr, must explicitly specify ssh.HostKeyCallback)

https://go-review.googlesource.com/c/crypto/+/38701