Create env vars to override the full worker image ref

This will allow advanced users more flexability in how
the worker images are specified. Specifically this allows
changing the image name itself and also allows for digest-based
identifiers (rather than using only tags)

Applies to ManageIQ/manageiq-pods#557

app/models/miq_ui_worker.rb

@@ -41,4 +41,8 @@ def container_port
   def container_image_name
     "manageiq-ui-worker"
   end
+
+  def container_image
+    ENV["UI_WORKER_IMAGE"] || default_image
+  end
 end

app/models/miq_worker/container_common.rb

@@ -18,7 +18,7 @@ def configure_worker_deployment(definition, replicas = 0)
         container[:imagePullPolicy] = "IfNotPresent"
       end
 
-      container[:image] = "#{container_image_namespace}/#{container_image_name}:#{container_image_tag}"
+      container[:image] = container_image
       container[:env] << {:name => "WORKER_CLASS_NAME", :value => self.class.name}
       container[:env] << {:name => "BUNDLER_GROUPS", :value => self.class.bundler_groups.join(",")}
     end
@@ -32,6 +32,14 @@ def zone_selector
       {"#{Vmdb::Appliance.PRODUCT_NAME.downcase}/zone-#{MiqServer.my_zone}" => "true"}
     end
 
+    def container_image
+      ENV["BASE_WORKER_IMAGE"] || default_image
+    end
+
+    def default_image
+      "#{container_image_namespace}/#{container_image_name}:#{container_image_tag}"
+    end
+
     def container_image_namespace
       ENV["CONTAINER_IMAGE_NAMESPACE"]
     end

app/models/miq_worker/service_worker.rb

@@ -52,5 +52,9 @@ def container_port
     def container_image_name
       "manageiq-webserver-worker"
     end
+
+    def container_image
+      ENV["WEBSERVER_WORKER_IMAGE"] || default_image
+    end
   end
 end

spec/models/miq_worker/container_common_spec.rb

@@ -92,4 +92,45 @@ def deployment_name_for(name)
       worker.scale_deployment
     end
   end
+
+  describe "#container_image" do
+    let(:generic_worker) { MiqGenericWorker.new }
+    let(:ui_worker)      { MiqUiWorker.new }
+    let(:api_worker)     { MiqWebServiceWorker.new }
+
+    it "uses the BASE_WORKER_IMAGE value for a generic worker" do
+      image_ref = "registry.example.com/manageiq/manageiq-test@sha256:2997e41a1195df90d8daf9714b619c9ae0c053f3d79e39bd8ed2d18b3c8da52a"
+      stub_const("ENV", ENV.to_h.merge("BASE_WORKER_IMAGE" => image_ref))
+      expect(generic_worker.container_image).to eq(image_ref)
+    end
+
+    it "uses the UI_WORKER_IMAGE value for a UI worker" do
+      image_ref = "registry.example.com/manageiq/manageiq-ui-test@sha256:2997e41a1195df90d8daf9714b619c9ae0c053f3d79e39bd8ed2d18b3c8da52a"
+      stub_const("ENV", ENV.to_h.merge("UI_WORKER_IMAGE" => image_ref))
+      expect(ui_worker.container_image).to eq(image_ref)
+    end
+
+    it "uses the WEBSERVER_WORKER_IMAGE value for an API worker" do
+      image_ref = "registry.example.com/manageiq/manageiq-web-test@sha256:2997e41a1195df90d8daf9714b619c9ae0c053f3d79e39bd8ed2d18b3c8da52a"
+      stub_const("ENV", ENV.to_h.merge("WEBSERVER_WORKER_IMAGE" => image_ref))
+      expect(api_worker.container_image).to eq(image_ref)
+    end
+
+    context "when CONTAINER_IMAGE_NAMESPACE is set" do
+      before { stub_const("ENV", ENV.to_h.merge("CONTAINER_IMAGE_NAMESPACE" => "registry.example.com/manageiq")) }
+
+      it "uses the correct default value" do
+        expect(generic_worker.container_image).to eq("registry.example.com/manageiq/manageiq-base-worker:latest")
+        expect(ui_worker.container_image).to eq("registry.example.com/manageiq/manageiq-ui-worker:latest")
+        expect(api_worker.container_image).to eq("registry.example.com/manageiq/manageiq-webserver-worker:latest")
+      end
+
+      it "allows tag overrides" do
+        stub_const("ENV", ENV.to_h.merge("CONTAINER_IMAGE_TAG" => "jansa-1"))
+        expect(generic_worker.container_image).to eq("registry.example.com/manageiq/manageiq-base-worker:jansa-1")
+        expect(ui_worker.container_image).to eq("registry.example.com/manageiq/manageiq-ui-worker:jansa-1")
+        expect(api_worker.container_image).to eq("registry.example.com/manageiq/manageiq-webserver-worker:jansa-1")
+      end
+    end
+  end
 end