Added poller disablement via settings

Necessary to disable pollers, if desired. Can be handy for deployment purposes should you not want these pollers to run and only have access to the environment variables.

Issue: 187
Milestone: minor

app/aspects/firmware/poller.rb

@@ -8,7 +8,7 @@ module Terminus
     module Firmware
       # Polls the Core Firmware API on a scheduled interval for new firmware versions.
       class Poller
-        include Deps["aspects.firmware.synchronizer"]
+        include Deps[:settings, "aspects.firmware.synchronizer"]
         include Initable[kernel: Kernel]
         include Dry::Monads[:result]
 
@@ -29,10 +29,14 @@ module Terminus
 
         def keep_alive seconds
           kernel.loop do
-            synchronizer.call
+            sync_or_skip
             kernel.sleep seconds
           end
         end
+
+        def sync_or_skip
+          settings.firmware_poller ? synchronizer.call : kernel.puts("Firmware polling disabled.")
+        end
       end
     end
   end

app/aspects/models/poller.rb

@@ -8,7 +8,7 @@ module Terminus
     module Models
       # Polls the Core Models API on a scheduled interval for new (or updated) models.
       class Poller
-        include Deps["aspects.models.synchronizer"]
+        include Deps[:settings, "aspects.models.synchronizer"]
         include Initable[kernel: Kernel]
         include Dry::Monads[:result]
 
@@ -29,10 +29,14 @@ module Terminus
 
         def keep_alive seconds
           kernel.loop do
-            synchronizer.call
+            sync_or_skip
             kernel.sleep seconds
           end
         end
+
+        def sync_or_skip
+          settings.model_poller ? synchronizer.call : kernel.puts("Model polling disabled.")
+        end
       end
     end
   end

app/aspects/screens/poller.rb

@@ -7,7 +7,12 @@ module Terminus
     module Screens
       # Polls the Core Display API on a scheduled interval for new images to display locally.
       class Poller
-        include Deps[:trmnl_api, "aspects.screens.synchronizer", repository: "repositories.device"]
+        include Deps[
+          :settings,
+          :trmnl_api,
+          "aspects.screens.synchronizer",
+          repository: "repositories.device"
+        ]
         include Initable[kernel: Kernel]
         include Dry::Monads[:result]
 
@@ -28,14 +33,18 @@ module Terminus
 
         def keep_alive seconds
           kernel.loop do
-            process_devices
+            sync_or_skip
             kernel.sleep seconds
           end
         end
 
-        def process_devices = repository.all.select(&:proxy).each { |device| process device }
+        def sync_or_skip
+          settings.screen_poller ? process_devices : kernel.puts("Screen polling disabled.")
+        end
 
-        def process device
+        def process_devices = repository.all.select(&:proxy).each { |device| sync device }
+
+        def sync device
           trmnl_api.display(token: device.api_key).bind { |record| synchronizer.call record }
         end
       end

spec/app/aspects/firmware/poller_spec.rb

@@ -8,6 +8,8 @@ RSpec.describe Terminus::Aspects::Firmware::Poller do
   let(:synchronizer) { instance_spy Terminus::Aspects::Firmware::Synchronizer }
   let(:kernel) { class_spy Kernel, sleep: 0 }
 
+  include_context "with main application"
+
   describe "#call" do
     before { allow(kernel).to receive(:loop).and_yield }
 
@@ -29,5 +31,20 @@ RSpec.describe Terminus::Aspects::Firmware::Poller do
       poller.call
       expect(synchronizer).to have_received(:call)
     end
+
+    context "when disabled" do
+      before do
+        allow(settings).to receive(:firmware_poller).and_return false
+        poller.call
+      end
+
+      it "prints message" do
+        expect(kernel).to have_received(:puts).with("Firmware polling disabled.")
+      end
+
+      it "doesn't synchronize" do
+        expect(synchronizer).not_to have_received(:call)
+      end
+    end
   end
 end

spec/app/aspects/models/poller_spec.rb

@@ -8,6 +8,8 @@ RSpec.describe Terminus::Aspects::Models::Poller do
   let(:synchronizer) { instance_spy Terminus::Aspects::Models::Synchronizer }
   let(:kernel) { class_spy Kernel, sleep: 0 }
 
+  include_context "with main application"
+
   describe "#call" do
     before { allow(kernel).to receive(:loop).and_yield }
 
@@ -29,5 +31,20 @@ RSpec.describe Terminus::Aspects::Models::Poller do
       poller.call
       expect(synchronizer).to have_received(:call)
     end
+
+    context "when disabled" do
+      before do
+        allow(settings).to receive(:model_poller).and_return false
+        poller.call
+      end
+
+      it "prints message" do
+        expect(kernel).to have_received(:puts).with("Model polling disabled.")
+      end
+
+      it "doesn't synchronize" do
+        expect(synchronizer).not_to have_received(:call)
+      end
+    end
   end
 end

spec/app/aspects/screens/poller_spec.rb

@@ -15,6 +15,8 @@ RSpec.describe Terminus::Aspects::Screens::Poller, :db do
 
   let(:synchronizer) { instance_spy Terminus::Aspects::Screens::Synchronizer }
 
+  include_context "with main application"
+
   describe "#call" do
     let(:devices) { [Factory[:device, proxy: true]] }
 
@@ -73,5 +75,20 @@ RSpec.describe Terminus::Aspects::Screens::Poller, :db do
         expect(synchronizer).not_to have_received(:call)
       end
     end
+
+    context "when disabled" do
+      before do
+        allow(settings).to receive(:screen_poller).and_return false
+        poller.call
+      end
+
+      it "prints message" do
+        expect(kernel).to have_received(:puts).with("Screen polling disabled.")
+      end
+
+      it "doesn't synchronize" do
+        expect(synchronizer).not_to have_received(:call)
+      end
+    end
   end
 end