Switch to using the public AWS domain of the build machine

Rather than the configured domain, as the corresponding SSH key
shouldn't change for the AWS domain (whereas it does for the
configured domain, if the machine changes).

2 files changed, 29 insertions, 3 deletions

diff --git a/app/models/backends/terraform_aws/backend_methods.rb b/app/models/backends/terraform_aws/backend_methods.rb
index 89509bd..b21c83e 100644
--- a/app/models/backends/terraform_aws/backend_methods.rb
+++ b/app/models/backends/terraform_aws/backend_methods.rb
@@ -20,8 +20,12 @@
 
 module Backends::TerraformAws::BackendMethods
   def create_data_snapshot
+    remote_host = backend_latest_terraform_state.output_value(
+      'guix_daemon_public_dns'
+    )
+
     GovukGuix::CreateDataSnapshotJob.enqueue(
-      run_remotely_on_host: "ubuntu@guix-daemon.#{domain}",
+      run_remotely_on_host: "ubuntu@#{remote_host}",
       backend_type: self.class.name,
       backend_id: id
     )
@@ -101,6 +105,10 @@ module Backends::TerraformAws::BackendMethods
     )
   end
 
+  def backend_latest_terraform_state
+    backend_terraform_states.order(:id).last
+  end
+
   def status
     latest_terraform_state = backend_terraform_states.order(:id).last
 
diff --git a/app/models/backends/terraform_aws/mini_environment_methods.rb b/app/models/backends/terraform_aws/mini_environment_methods.rb
index e0fe03b..6049829 100644
--- a/app/models/backends/terraform_aws/mini_environment_methods.rb
+++ b/app/models/backends/terraform_aws/mini_environment_methods.rb
@@ -22,6 +22,14 @@ module Backends::TerraformAws::MiniEnvironmentMethods
   def build(mini_environment)
     slug = mini_environment.name.parameterize
 
+    remote_build_host =
+      mini_environment
+        .backend
+        .backend_latest_terraform_state
+        .output_value(
+          'guix_daemon_public_dns'
+        )
+
     GovukGuix::BuildMiniEnvironment.build(
       mini_environment.id,
       services: mini_environment.services.map(&:build_argument_string),
@@ -42,7 +50,7 @@ module Backends::TerraformAws::MiniEnvironmentMethods
           '/var/log/govuk-mini-environment-admin=/var/log'
         ]
       },
-      run_remotely_on_host: "ubuntu@guix-daemon.#{domain}"
+      run_remotely_on_host: "ubuntu@#{remote_build_host}"
     )
   end
 
@@ -74,13 +82,23 @@ module Backends::TerraformAws::MiniEnvironmentMethods
     end
   end
 
+  def terraform_states(mini_environment)
+    TerraformState.where(
+      state_id: mini_environment_state_id(mini_environment)
+    )
+  end
+
   def within_terraform_working_directory(mini_environment, &block)
     TerraformWorkingDirectory.new(
-      "mini_environment/#{mini_environment.id}",
+      mini_environment_state_id(mini_environment),
       'terraform/aws/mini_environment'
     ).within_working_directory(&block)
   end
 
+  def mini_environment_state_id(mini_environment)
+    "mini_environment/#{mini_environment.id}"
+  end
+
   def signon_url(mini_environment)
     "https://signon.#{mini_environment.name.parameterize}.#{domain}"
   end