From 2a6fe06ba3cffe7a018508145832052e2cefdb79 Mon Sep 17 00:00:00 2001
From: Rick Carlino <rick.carlino@gmail.com>
Date: Thu, 13 Feb 2020 13:10:48 -0600
Subject: [PATCH 1/2] Cap sensor readings to 5,000 count

---
 .../api/sensor_readings_controller.rb         | 22 ++++++++++++++++---
 .../api/sensor_readings/controller_spec.rb    | 19 ++++++++++++++--
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/app/controllers/api/sensor_readings_controller.rb b/app/controllers/api/sensor_readings_controller.rb
index a0e945873..65feb4c28 100644
--- a/app/controllers/api/sensor_readings_controller.rb
+++ b/app/controllers/api/sensor_readings_controller.rb
@@ -1,7 +1,10 @@
 module Api
   class SensorReadingsController < Api::AbstractController
+    LIMIT = 5000
+    before_action :clean_old
+
     def create
-        mutate SensorReadings::Create.run(raw_json, device: current_device)
+      mutate SensorReadings::Create.run(raw_json, device: current_device)
     end
 
     def index
@@ -17,10 +20,23 @@ module Api
       render json: ""
     end
 
-  private
+    private
+
+    def clean_old
+      if current_device.sensor_readings.count > LIMIT
+        current_device
+          .sensor_readings
+          .where
+          .not(id: readings.pluck(:id))
+          .delete_all
+      end
+    end
 
     def readings
-      SensorReading.where(device: current_device)
+      @readings ||= SensorReading
+        .where(device: current_device)
+        .order(created_at: :desc)
+        .limit(LIMIT)
     end
 
     def reading
diff --git a/spec/controllers/api/sensor_readings/controller_spec.rb b/spec/controllers/api/sensor_readings/controller_spec.rb
index 19a1e8612..9f0aea4fb 100644
--- a/spec/controllers/api/sensor_readings/controller_spec.rb
+++ b/spec/controllers/api/sensor_readings/controller_spec.rb
@@ -18,7 +18,7 @@ describe Api::SensorReadingsController do
           x: nil,
           y: 1,
           z: 2,
-          mode: 1
+          mode: 1,
         }.to_json,
         params: { format: :json }
 
@@ -40,7 +40,7 @@ describe Api::SensorReadingsController do
           y: 1,
           z: 2,
           mode: 1,
-          read_at: read_at
+          read_at: read_at,
         }.to_json,
         params: { format: :json }
 
@@ -105,5 +105,20 @@ describe Api::SensorReadingsController do
       post :create, body: {}.to_json
       expect(response.status).to eq(401)
     end
+
+    it "cleans up excess logs" do
+      const_reassign(Api::SensorReadingsController, :LIMIT, 5)
+      sign_in user
+      10.times do |n|
+        FactoryBot.create(:sensor_reading,
+                          device: user.device,
+                          created_at: n.minutes.ago)
+      end
+      expect(user.device.sensor_readings.count).to eq(10)
+      get :index, params: { format: :json }
+      expect(json.count).to eq(5)
+      expect(user.device.sensor_readings.count).to eq(5)
+      const_reassign(Api::SensorReadingsController, :LIMIT, 5000)
+    end
   end
 end

From c1a9bc63bf0b97ed4228a3ebe6937ce41056b3d8 Mon Sep 17 00:00:00 2001
From: Rick Carlino <rick.carlino@gmail.com>
Date: Thu, 13 Feb 2020 13:15:37 -0600
Subject: [PATCH 2/2] SensorReadingController test improvement

---
 spec/controllers/api/sensor_readings/controller_spec.rb | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/spec/controllers/api/sensor_readings/controller_spec.rb b/spec/controllers/api/sensor_readings/controller_spec.rb
index 9f0aea4fb..7f544917c 100644
--- a/spec/controllers/api/sensor_readings/controller_spec.rb
+++ b/spec/controllers/api/sensor_readings/controller_spec.rb
@@ -119,6 +119,9 @@ describe Api::SensorReadingsController do
       expect(json.count).to eq(5)
       expect(user.device.sensor_readings.count).to eq(5)
       const_reassign(Api::SensorReadingsController, :LIMIT, 5000)
+      first = (json.first[:created_at])
+      last = (json.last[:created_at])
+      expect(first).to be > last
     end
   end
 end