Add feature flag for immunisations fhir api

This flag is designed to control any and all connectivity to the
Immunisations FHIR API.

Jira-Issue: MAV-1477

Author: misaka

app/lib/nhs/immunisations_api.rb

@@ -3,6 +3,14 @@
 module NHS::ImmunisationsAPI
   class << self
     def record_immunisation(vaccination_record)
+      unless Flipper.enabled?(:immunisations_fhir_api_integration)
+        Rails.logger.info(
+          "Not syncing vaccination record to immunisations API as the feature" \
+            " flag is disabled: #{vaccination_record.id}"
+        )
+        return
+      end
+
       response =
         NHS::API.connection.post(
           "/immunisation-fhir-api/FHIR/R4/Immunization",
@@ -26,7 +34,7 @@ def record_immunisation(vaccination_record)
       end
     rescue Faraday::ClientError => e
       if (diagnostics = extract_error_diagnostics(e&.response)).present?
-        raise "Error syncing vaccination #{vaccination_record.id} record to" \
+        raise "Error syncing vaccination record #{vaccination_record.id} to" \
                 " Immunisations API: #{diagnostics}"
       else
         raise

config/feature_flags.yml

@@ -8,3 +8,6 @@ dev_tools: Developer tools useful for testing and debugging.
 mesh_jobs: Export vaccination records to MESH automatically.
 
 offline_working: Prototype support for using Mavis offline.
+
+immunisations_fhir_api_integration: Master switch to control communications with
+  NHS Immunistaions FHIR API.

spec/features/cli_vaccination_records_sync_spec.rb

@@ -78,6 +78,8 @@ def and_the_nhs_api_is_available
             "https://sandbox.api.service.nhs.uk/immunisation-fhir-api/Immunization/11112222-3333-4444-5555-666677778888"
         }
       )
+
+    Flipper.enable :immunisations_fhir_api_integration
   end
 
   def when_i_run_the_sync_command

spec/lib/nhs/immunisations_api_spec.rb

@@ -47,21 +47,22 @@
       created_at: Time.zone.parse("2021-02-07T13:28:17.271+00:00")
     )
   end
+  let!(:stubbed_request) do
+    stub_request(
+      :post,
+      "https://sandbox.api.service.nhs.uk/immunisation-fhir-api/FHIR/R4/Immunization"
+    ).to_return(
+      status: 201,
+      body: "",
+      headers: {
+        location:
+          "https://sandbox.api.service.nhs.uk/immunisation-fhir-api/Immunization/ffff1111-eeee-2222-dddd-3333eeee4444"
+      }
+    )
+  end
 
   describe "record_immunisation" do
-    before do
-      stub_request(
-        :post,
-        "https://sandbox.api.service.nhs.uk/immunisation-fhir-api/FHIR/R4/Immunization"
-      ).to_return(
-        status: 201,
-        body: "",
-        headers: {
-          location:
-            "https://sandbox.api.service.nhs.uk/immunisation-fhir-api/Immunization/ffff1111-eeee-2222-dddd-3333eeee4444"
-        }
-      )
-    end
+    before { Flipper.enable(:immunisations_fhir_api_integration) }
 
     it "sends the correct JSON payload" do
       expected_body =
@@ -171,13 +172,14 @@
 
       context "4XX error" do
         let(:status) { 404 }
+        let(:diagnostics) { "Invalid patient ID" }
 
         it "raises an error with the diagnostic message" do
           expect {
             described_class.record_immunisation(vaccination_record)
           }.to raise_error(
             StandardError,
-            "Error syncing vaccination #{vaccination_record.id} record to" \
+            "Error syncing vaccination record #{vaccination_record.id} to" \
               " Immunisations API: Invalid patient ID"
           )
         end
@@ -198,5 +200,15 @@
         end
       end
     end
+
+    context "the immunisations_fhir_api_integration feature flag is disabled" do
+      before { Flipper.disable(:immunisations_fhir_api_integration) }
+
+      it "does not make a request to the NHS API" do
+        described_class.record_immunisation(vaccination_record)
+
+        expect(stubbed_request).not_to have_been_made
+      end
+    end
   end
 end