MSFT sync: fix bug in pagination metrics tagging

refs INTEROP-6798
flag=microsoft_group_enrollments_syncing

Test plan:
- specs should be enough

Change-Id: Ie848d0844a4966c3ed6c14e313e10f102eb4b7c8
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/267808
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Ryan Hawkins <ryan.hawkins@instructure.com>
QA-Review: Ryan Hawkins <ryan.hawkins@instructure.com>
Product-Review: Evan Battaglia <ebattaglia@instructure.com>

lib/microsoft_sync/graph_service_http.rb

@@ -202,7 +202,10 @@ module MicrosoftSync
       end
     end
 
-    def statsd_tags_for_request(method, path)
+    def statsd_tags_for_request(method, path_or_url)
+      # Strip https, hostname, "v1.0"
+      path = path_or_url.gsub(%r{^https?://[^/]*/[^/]*/}, '')
+
       {
         msft_endpoint: InstStatsd::Statsd.escape("#{method.to_s.downcase}_#{path.split('/').first}")
       }

spec/lib/microsoft_sync/graph_service_http_spec.rb

@@ -104,7 +104,14 @@ describe MicrosoftSync::GraphServiceHttp do
       end
     end
 
-    # it 'uses the correct msft_endpoint when passed in a url' TODO this bug hasn't been fixed yet
+    it 'uses the correct msft_endpoint when passed in a url' do
+      # pagination "next" links are complete URLs
+      subject.request(:get, 'https://graph.microsoft.com/v1.0/foo/bar', quota: [1, 0])
+      expect(InstStatsd::Statsd).to have_received(:count)
+        .with("microsoft_sync.graph_service.quota_read", 1, tags: {msft_endpoint: 'get_foo'})
+      expect(InstStatsd::Statsd).to have_received(:increment)
+        .with("microsoft_sync.graph_service.success", tags: {msft_endpoint: 'get_foo'})
+    end
   end
 
   describe '#expand_options' do