Add performance deltas between app deployments on Merge Request widget

2 files changed, 43 insertions, 11 deletions

diff --git a/app/assets/javascripts/lib/utils/number_utils.js b/app/assets/javascripts/lib/utils/number_utils.js
index f1b07408671..57394097944 100644
--- a/app/assets/javascripts/lib/utils/number_utils.js
+++ b/app/assets/javascripts/lib/utils/number_utils.js
@@ -42,3 +42,13 @@ export function formatRelevantDigits(number) {
 export function bytesToKiB(number) {
   return number / BYTES_IN_KIB;
 }
+
+/**
+ * Utility function that calculates MiB of the given bytes.
+ *
+ * @param  {Number} number bytes
+ * @return {Number}        MiB
+ */
+export function bytesToMiB(number) {
+  return number / (BYTES_IN_KIB * BYTES_IN_KIB);
+}
diff --git a/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_memory_usage.js b/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_memory_usage.js
index 486b13e60af..8155218681c 100644
--- a/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_memory_usage.js
+++ b/app/assets/javascripts/vue_merge_request_widget/components/mr_widget_memory_usage.js
@@ -1,4 +1,6 @@
 import statusCodes from '~/lib/utils/http_status';
+import { bytesToMiB } from '~/lib/utils/number_utils';
+
 import MemoryGraph from '../../vue_shared/components/memory_graph';
 import MRWidgetService from '../services/mr_widget_service';
 
@@ -9,8 +11,8 @@ export default {
   },
   data() {
     return {
-      // memoryFrom: 0,
-      // memoryTo: 0,
+      memoryFrom: 0,
+      memoryTo: 0,
       memoryMetrics: [],
       deploymentTime: 0,
       hasMetrics: false,
@@ -35,18 +37,38 @@ export default {
     shouldShowMetricsUnavailable() {
       return !this.loadingMetrics && !this.hasMetrics && !this.loadFailed;
     },
+    memoryChangeType() {
+      const memoryTo = Number(this.memoryTo);
+      const memoryFrom = Number(this.memoryFrom);
+
+      if (memoryTo > memoryFrom) {
+        return 'increased';
+      } else if (memoryTo < memoryFrom) {
+        return 'decreased';
+      }
+
+      return 'unchanged';
+    },
   },
   methods: {
+    getMegabytes(bytesString) {
+      const valueInBytes = Number(bytesString).toFixed(2);
+      return (bytesToMiB(valueInBytes)).toFixed(2);
+    },
     computeGraphData(metrics, deploymentTime) {
       this.loadingMetrics = false;
-      const { memory_values } = metrics;
-      // if (memory_previous.length > 0) {
-      //   this.memoryFrom = Number(memory_previous[0].value[1]).toFixed(2);
-      // }
-      //
-      // if (memory_current.length > 0) {
-      //   this.memoryTo = Number(memory_current[0].value[1]).toFixed(2);
-      // }
+      const { memory_before, memory_after, memory_values } = metrics;
+
+      // Both `memory_before` and `memory_after` objects
+      // have peculiar structure where accessing only a specific
+      // index yeilds correct value that we can use to show memory delta.
+      if (memory_before.length > 0) {
+        this.memoryFrom = this.getMegabytes(memory_before[0].value[1]);
+      }
+
+      if (memory_after.length > 0) {
+        this.memoryTo = this.getMegabytes(memory_after[0].value[1]);
+      }
 
       if (memory_values.length > 0) {
         this.hasMetrics = true;
@@ -102,7 +124,7 @@ export default {
       <p
         v-if="shouldShowMemoryGraph"
         class="usage-info js-usage-info">
-        Deployment memory usage:
+        Memory usage <b>{{memoryChangeType}}</b> from {{memoryFrom}}MB to {{memoryTo}}MB
       </p>
       <p
         v-if="shouldShowLoadFailure"