Render version of Perfdash on UI

Author: kishen-v

perfdash/Makefile

@@ -1,7 +1,9 @@
 all: push
 
 # See deployment.yaml for the version currently running-- bump this ahead before rebuilding!
+# Additionally please ensure to update the same in www/VERSION
 TAG?=2.56
+WWW_VERSION=$(shell cat www/VERSION)
 
 REPO?=gcr.io/k8s-staging-perf-tests
 
@@ -24,7 +26,11 @@ run: perfdash
 # Use buildkit to have "COPY --chmod=" support (availability of it in "regular" docker build depends on docker version).
 .PHONY: container
 container:
+ifneq ($(TAG),$(WWW_VERSION))
+	$(error Version mismatch! Makefile=$(TAG), www/VERSION=$(WWW_VERSION). Please align before building)
+else
 	DOCKER_BUILDKIT=1 docker build --pull -t $(REPO)/perfdash:$(TAG) .
+endif
 
 .PHONY: push
 push: container

perfdash/www/VERSION

@@ -0,0 +1 @@
+2.56

perfdash/www/index.html

@@ -54,9 +54,15 @@ <h1 class="md-display-2">Performance Dashboard</h1>
         </canvas>
         <p style="text-align: center">Runs over time</p>
       </div>
-      <p style="font-size: x-small; font-style: italic">
-        Click a data point to see build logs. CTRL+click anywhere to trim outliers.
+      <p style="font-size: x-small; font-style: italic; display: flex; justify-content: space-between;">
+        <span>Click a data point to see build logs. CTRL+click anywhere to trim outliers.</span>
+        <span>Version: <span id="version"></span></span>
       </p>
+      <script>
+        fetch('VERSION')
+                .then(resp => resp.text())
+                .then(version => document.getElementById('version').innerText = version)
+      </script>
       <!-- Angular Material Dependencies -->
       <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular.min.js"></script>
       <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular-animate.min.js"></script>