Add backtrace to Gitaly performance bar

This adds the backtrace to a table to show exactly where the Gitaly call
was made to make it easier to understand where the call originated.

This change also collapses the details in the same row to improve the
usability when there is a backtrace.

7 files changed, 68 insertions, 15 deletions

diff --git a/app/assets/javascripts/performance_bar/components/detailed_metric.vue b/app/assets/javascripts/performance_bar/components/detailed_metric.vue
index c729198c1d3..dec2a498173 100644
--- a/app/assets/javascripts/performance_bar/components/detailed_metric.vue
+++ b/app/assets/javascripts/performance_bar/components/detailed_metric.vue
@@ -1,9 +1,11 @@
 <script>
 import GlModal from '~/vue_shared/components/gl_modal.vue';
+import Icon from '~/vue_shared/components/icon.vue';
 
 export default {
   components: {
     GlModal,
+    Icon,
   },
   props: {
     currentRequest: {
@@ -57,9 +59,31 @@ export default {
         <template v-if="detailsList.length">
           <tr v-for="(item, index) in detailsList" :key="index">
             <td>
-              <strong>{{ item.duration }}ms</strong>
+              <span>{{ item.duration }}ms</span>
+            </td>
+            <td>
+              <div class="js-toggle-container">
+                <div
+                  v-for="(key, keyIndex) in keys"
+                  :key="key"
+                  class="break-word"
+                  :class="{ 'mb-3 bold': keyIndex == 0 }"
+                >
+                  {{ item[key] }}
+                  <button
+                    v-if="keyIndex == 0 && item.backtrace"
+                    class="text-expander js-toggle-button"
+                    type="button"
+                    :aria-label="__('Toggle backtrace')"
+                  >
+                    <icon :size="12" name="ellipsis_h" />
+                  </button>
+                </div>
+                <pre v-if="item.backtrace" class="backtrace-row js-toggle-content mt-2">{{
+                  item.backtrace
+                }}</pre>
+              </div>
             </td>
-            <td v-for="key in keys" :key="key" class="break-word">{{ item[key] }}</td>
           </tr>
         </template>
         <template v-else>
diff --git a/app/assets/stylesheets/performance_bar.scss b/app/assets/stylesheets/performance_bar.scss
index 9c01a2f8bda..5a8940ffd6d 100644
--- a/app/assets/stylesheets/performance_bar.scss
+++ b/app/assets/stylesheets/performance_bar.scss
@@ -79,8 +79,12 @@
   table {
     color: $black;
 
-    strong {
-      color: $black;
+    td {
+      vertical-align: top;
+    }
+
+    .backtrace-row {
+      display: none;
     }
   }
 
diff --git a/changelogs/unreleased/sh-add-gitaly-backtrace.yml b/changelogs/unreleased/sh-add-gitaly-backtrace.yml
new file mode 100644
index 00000000000..1515edd6db9
--- /dev/null
+++ b/changelogs/unreleased/sh-add-gitaly-backtrace.yml
@@ -0,0 +1,5 @@
+---
+title: Add backtrace to Gitaly performance bar
+merge_request: 27345
+author:
+type: other
diff --git a/lib/gitlab/gitaly_client.rb b/lib/gitlab/gitaly_client.rb
index 35565b68388..726c4d95da9 100644
--- a/lib/gitlab/gitaly_client.rb
+++ b/lib/gitlab/gitaly_client.rb
@@ -165,7 +165,10 @@ module Gitlab
         current_transaction_labels.merge(gitaly_service: service.to_s, rpc: rpc.to_s),
         duration)
 
-      add_call_details(feature: "#{service}##{rpc}", duration: duration, request: request_hash, rpc: rpc)
+      if peek_enabled?
+        add_call_details(feature: "#{service}##{rpc}", duration: duration, request: request_hash, rpc: rpc,
+                         backtrace: Gitlab::Profiler.clean_backtrace(caller))
+      end
     end
 
     def self.query_time
@@ -350,15 +353,17 @@ module Gitlab
       Gitlab::SafeRequestStore["gitaly_call_permitted"] = 0
     end
 
-    def self.add_call_details(details)
-      return unless Gitlab::SafeRequestStore[:peek_enabled]
+    def self.peek_enabled?
+      Gitlab::SafeRequestStore[:peek_enabled]
+    end
 
+    def self.add_call_details(details)
       Gitlab::SafeRequestStore['gitaly_call_details'] ||= []
       Gitlab::SafeRequestStore['gitaly_call_details'] << details
     end
 
     def self.list_call_details
-      return [] unless Gitlab::SafeRequestStore[:peek_enabled]
+      return [] unless peek_enabled?
 
       Gitlab::SafeRequestStore['gitaly_call_details'] || []
     end
diff --git a/lib/gitlab/profiler.rb b/lib/gitlab/profiler.rb
index 93a9fcf1591..28ed587f5c7 100644
--- a/lib/gitlab/profiler.rb
+++ b/lib/gitlab/profiler.rb
@@ -16,7 +16,11 @@ module Gitlab
       ee/lib/gitlab/middleware/
       lib/gitlab/performance_bar/
       lib/gitlab/request_profiler/
+      lib/gitlab/query_limiting/
+      lib/gitlab/tracing/
       lib/gitlab/profiler.rb
+      lib/gitlab/correlation_id.rb
+      lib/gitlab/webpack/dev_server_middleware.rb
     ].freeze
 
     # Takes a URL to profile (can be a fully-qualified URL, or an absolute path)
diff --git a/locale/gitlab.pot b/locale/gitlab.pot
index e6e161a2b27..fb53ed0a00f 100644
--- a/locale/gitlab.pot
+++ b/locale/gitlab.pot
@@ -9559,6 +9559,9 @@ msgstr ""
 msgid "Toggle Sidebar"
 msgstr ""
 
+msgid "Toggle backtrace"
+msgstr ""
+
 msgid "Toggle comments for this file"
 msgstr ""
 
diff --git a/spec/javascripts/performance_bar/components/detailed_metric_spec.js b/spec/javascripts/performance_bar/components/detailed_metric_spec.js
index e91685e50c5..8a7aa057186 100644
--- a/spec/javascripts/performance_bar/components/detailed_metric_spec.js
+++ b/spec/javascripts/performance_bar/components/detailed_metric_spec.js
@@ -27,8 +27,8 @@ describe('detailedMetric', () => {
 
   describe('when the current request has details', () => {
     const requestDetails = [
-      { duration: '100', feature: 'find_commit', request: 'abcdef' },
-      { duration: '23', feature: 'rebase_in_progress', request: '' },
+      { duration: '100', feature: 'find_commit', request: 'abcdef', backtrace: ['hello', 'world'] },
+      { duration: '23', feature: 'rebase_in_progress', request: '', backtrace: ['world', 'hello'] },
     ];
 
     beforeEach(() => {
@@ -54,9 +54,11 @@ describe('detailedMetric', () => {
     });
 
     it('adds a modal with a table of the details', () => {
-      vm.$el.querySelectorAll('.performance-bar-modal td strong').forEach((duration, index) => {
-        expect(duration.innerText).toContain(requestDetails[index].duration);
-      });
+      vm.$el
+        .querySelectorAll('.performance-bar-modal td:nth-child(1)')
+        .forEach((duration, index) => {
+          expect(duration.innerText).toContain(requestDetails[index].duration);
+        });
 
       vm.$el
         .querySelectorAll('.performance-bar-modal td:nth-child(2)')
@@ -65,10 +67,16 @@ describe('detailedMetric', () => {
         });
 
       vm.$el
-        .querySelectorAll('.performance-bar-modal td:nth-child(3)')
+        .querySelectorAll('.performance-bar-modal td:nth-child(2)')
         .forEach((request, index) => {
-          expect(request.innerText).toEqual(requestDetails[index].request);
+          expect(request.innerText).toContain(requestDetails[index].request);
         });
+
+      expect(vm.$el.querySelector('.text-expander.js-toggle-button')).not.toBeNull();
+
+      vm.$el.querySelectorAll('.performance-bar-modal td:nth-child(2)').forEach(request => {
+        expect(request.innerText).toContain('world');
+      });
     });
 
     it('displays the metric name', () => {