From fecad19b913e77833a52a6a8a8f258e80c74df55 Mon Sep 17 00:00:00 2001
From: simon lehericey <mail@simon.lehericey.net>
Date: Sun, 21 Jun 2020 18:34:59 +0200
Subject: [PATCH] add maintenance mode

---
 app/controllers/ping_controller.rb       | 11 ++++++++---
 spec/controllers/ping_controller_spec.rb | 10 ++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/app/controllers/ping_controller.rb b/app/controllers/ping_controller.rb
index 2ac9e20ff..08f439aec 100644
--- a/app/controllers/ping_controller.rb
+++ b/app/controllers/ping_controller.rb
@@ -1,11 +1,16 @@
 class PingController < ApplicationController
   def index
     Rails.logger.silence do
-      if (ActiveRecord::Base.connected?)
-        head :ok, content_type: "application/json"
+      status_code = if File.file?(Rails.root.join("maintenance"))
+        # See https://cbonte.github.io/haproxy-dconv/2.0/configuration.html#4.2-http-check%20disable-on-404
+        :not_found
+      elsif (ActiveRecord::Base.connected?)
+        :ok
       else
-        head :internal_server_error, content_type: "application/json"
+        :internal_server_error
       end
+
+      head status_code, content_type: "application/json"
     end
   end
 end
diff --git a/spec/controllers/ping_controller_spec.rb b/spec/controllers/ping_controller_spec.rb
index 0649048f7..a288b69c1 100644
--- a/spec/controllers/ping_controller_spec.rb
+++ b/spec/controllers/ping_controller_spec.rb
@@ -11,5 +11,15 @@ describe PingController, type: :controller do
 
       it { expect(subject.status).to eq 500 }
     end
+
+    context 'when a maintenance file is present' do
+      before do
+        allow(File).to receive(:file?).and_return(true)
+      end
+
+      it 'tells HAProxy that the app is in maintenance, but will be available again soon' do
+        expect(subject.status).to eq 404
+      end
+    end
   end
 end