Module: Xshellz::Ssh

Defined in:
lib/xshellz/ssh.rb

Overview

SSH/SFTP data plane, behind a small transport interface for testability.

The real implementation (NetSshTransport) speaks SSH as root to the sandbox. Host keys are auto-accepted (+verify_host_key: :never+): sandboxes are throwaway boxes whose host keys are generated at spawn time, so there is no out-of-band fingerprint to pin against.

Defined Under Namespace

Classes: NetSshTransport

Constant Summary collapse

ENV_NAME = 
/\A[A-Za-z_][A-Za-z0-9_]*\z/

Class Method Summary collapse

Class Method Details

.build_shell_command(command, cwd: nil, env: nil) ⇒ Object

Wrap a command with optional cd and environment exports.

Environment variable names are validated (sshd rarely honours AcceptEnv, so variables are exported in the remote shell instead).



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# File 'lib/xshellz/ssh.rb', line 22

def self.build_shell_command(command, cwd: nil, env: nil)
  parts = []
  if env && !env.empty?
    exports = env.map do |key, value|
      raise Error, "Invalid environment variable name: #{key.inspect}" unless key.to_s.match?(ENV_NAME)

      "#{key}=#{Shellwords.escape(value.to_s)}"
    end
    parts << "export #{exports.join(" ")}"
  end
  parts << "cd #{Shellwords.escape(cwd)}" if cwd
  parts << command
  parts.join(" && ")
end

.load_private_key!(private_key) ⇒ Object

Load/validate an OpenSSH-format private key string; raises a helpful Xshellz::Error when it cannot be parsed.



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# File 'lib/xshellz/ssh.rb', line 39

def self.load_private_key!(private_key)
  Net::SSH::KeyFactory.load_data_private_key(private_key.to_s, nil, false)
rescue StandardError => e
  raise Error,
        "Could not load the private key. Expected an unencrypted " \
        "OpenSSH-format private key (e.g. Sandbox#private_key_openssh). " \
        "Details: #{e.class}: #{e.message}"
end