Neaten up SSH handling

Explicitly use the specified private key where possible. Also, use a
struct for the user, address and private key.

2 files changed, 38 insertions, 1 deletions

diff --git a/lib/remote_host.rb b/lib/remote_host.rb
new file mode 100644
index 0000000..9110394
--- /dev/null
+++ b/lib/remote_host.rb
@@ -0,0 +1,25 @@
+# GOV.UK Mini Environment Admin
+# Copyright © 2018  Christopher Baines <mail@cbaines.net>
+#
+# This file is part of the GOV.UK Mini Environment Admin.
+#
+# The GOV.UK Mini Environment Admin is free software: you can
+# redistribute it and/or modify it under the terms of the GNU Affero
+# General Public License as published by the Free Software Foundation,
+# either version 3 of the License, or (at your option) any later
+# version.
+#
+# The GOV.UK Mini Environment Admin is distributed in the hope that it
+# will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public
+# License along with the GOV.UK Mini Environment Admin.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+RemoteHost = Struct.new(:user, :address, :private_key) do
+  def user_at_address
+    "#{user}@#{address}"
+  end
+end
diff --git a/lib/shell_utils.rb b/lib/shell_utils.rb
index 0cd8947..75ee3ca 100644
--- a/lib/shell_utils.rb
+++ b/lib/shell_utils.rb
@@ -20,6 +20,7 @@
 
 require 'open3'
 require 'shellwords'
+require 'tempfile'
 
 module ShellUtils
   def run_command(*command, run_remotely_on_host: nil)
@@ -28,11 +29,19 @@ module ShellUtils
         Shellwords.escape(arg)
       end
 
+      identity_file = Tempfile.new(
+        'private-identity-file',
+        Rails.root.join('tmp')
+      )
+      identity_file.write(run_remotely_on_host.private_key)
+      identity_file.close
+
       command = [
         'ssh',
         # Use a automatically trust on first use model
         '-o', 'StrictHostKeyChecking=no',
-        run_remotely_on_host,
+        '-i', identity_file.path,
+        run_remotely_on_host.user_at_address,
         *command
       ]
     end
@@ -52,9 +61,12 @@ module ShellUtils
       unless exit_status == 0
         logger.error(self.class) { "failed, exit status #{exit_status}" }
 
+        identity_file.unlink if identity_file
         raise "Running #{command.join(' ')} failed:\n\n#{output.join}\n"
       end
 
+      identity_file.unlink if identity_file
+
       output
     end
   end