Merge pull request #20 from paulbouwer/improve_info_displayed

refactor: improve displayed information

Author: paulbouwer

README.md

@@ -5,8 +5,8 @@
 This container image can be deployed on a Kubernetes cluster. It runs a web app, that displays the following:
 
 - a default **Hello world!** message
-- the pod name
-- node os information
+- namespace, pod, and node details
+- container image details
 
 ![Hello world! from the hello-kubernetes image](hello-kubernetes.png)
 

deploy/helm/hello-kubernetes/templates/deployment.yaml

@@ -50,6 +50,20 @@ spec:
           - name: RENDER_PATH_PREFIX
             value: "{{ .Values.ingress.pathPrefix }}"
           {{- end }}
+          - name: KUBERNETES_NAMESPACE
+            valueFrom:
+              fieldRef:
+                fieldPath: metadata.namespace
+          - name: KUBERNETES_POD_NAME
+            valueFrom:
+              fieldRef:
+                fieldPath: metadata.name
+          - name: KUBERNETES_NODE_NAME
+            valueFrom:
+              fieldRef:
+                fieldPath: spec.nodeName
+          - name: CONTAINER_IMAGE
+            value: "{{ .Values.deployment.container.image.repository }}:{{ .Values.deployment.container.image.tag | default .Chart.AppVersion }}"
           {{- with .Values.deployment.resources }}
           resources:
             {{- toYaml . | nindent 12 }}

hello-kubernetes.png

@@ -1,6 +1,6 @@
 # Hello Kubernetes demo app
 
-A demo app that can be deployd to a Kubernetes cluster. It displays a message, the name of the pod and details of the node it's deployed to.
+A demo app that can be deployd to a Kubernetes cluster. It displays a message, and also namespace, pod, node and image details.
 
 ## Paths
 
@@ -17,5 +17,15 @@ The application can be configured via the following environment variables.
 | PORT | No | 8080 | The port that the app listens on. |
 | MESSAGE | No | "Hello world!" | The message displayed by the app. |
 | RENDER_PATH_PREFIX | No | "" | The path prefix to use when rendering the urls for the static assets in the handlebar templates. <br/> Must be used when app is deployed with an ingress using a backend path for traffic to app. |
-| HANDLER_PATH_PREFIX | No | "" | The path prefix to use by handlers when serving the static asset and services. <br/> Note: Must be used when app is deployed with an ingress that has a backend path for traffic to the app, but which does not rewrite the backend paths to '/'. |
+| HANDLER_PATH_PREFIX | No | "" | The path prefix to use by handlers when serving the dynamic and static assets. <br/> Note: Must be used when app is deployed with an ingress that has a backend path for traffic to the app, but which does not rewrite the backend paths to '/'. |
+| KUBERNETES_NAMESPACE | Yes | "-" | The Kubernetes namespace that the app has been deployed to. |
+| KUBERNETES_POD_NAME | Yes | hostname | The name of the Kubernetes pod that the app is deployed into. |
+| KUBERNETES_NODE_NAME | Yes | "-" | The name of the Kubernetes node that the app is deployed on. |
+| CONTAINER_IMAGE | Yes | "paulbouwer/hello-kubernetes:$(cat package.json \| jq -r .version)" | The name and tag of the container image running the app. |
 
+The application relies on the following files for configuration and operational information.
+
+| File | Required | Information | Description |
+| ---- | -------- | ----------- | ----------- |
+| package.json | Yes | `.version` | The release version is used when the CONTAINER_IMAGE env is not provided. |
+| info.json | Yes | `.containerImageArch` | The container image architecture is used for display. This file will be overwritten in future versions as part of the container image build process when multi-arch images are supported. |

src/app/README.md

@@ -0,0 +1,3 @@
+{
+  "containerImageArch": "linux/amd64"
+}

src/app/info.json

@@ -1,6 +1,7 @@
 const express = require('express');
 const exphbs  = require('express-handlebars');
 const os = require("os");
+const fs = require('fs');
 
 const pino = require('pino');
 const expressPino = require('express-pino-logger');
@@ -27,13 +28,25 @@ var handlerPathPrefix = (
     ''
 );
 
+var namespace = process.env.KUBERNETES_NAMESPACE || '-';
+var podName = process.env.KUBERNETES_POD_NAME || os.hostname();
+var nodeName = process.env.KUBERNETES_NODE_NAME || '-';
+var nodeOS = os.type() + ' ' + os.release();
+var applicationVersion = JSON.parse(fs.readFileSync('package.json', 'utf8')).version;
+var containerImage = process.env.CONTAINER_IMAGE || 'paulbouwer/hello-kubernetes:' + applicationVersion
+var containerImageArch = JSON.parse(fs.readFileSync('info.json', 'utf8')).containerImageArch;
+
 logger.debug();
 logger.debug('Configuration');
 logger.debug('-----------------------------------------------------');
 logger.debug('PORT=' + process.env.PORT);
 logger.debug('MESSAGE=' + process.env.MESSAGE);
 logger.debug('RENDER_PATH_PREFIX=' + process.env.RENDER_PATH_PREFIX);
 logger.debug('HANDLER_PATH_PREFIX=' + process.env.HANDLER_PATH_PREFIX);
+logger.debug('KUBERNETES_NAMESPACE=' + process.env.KUBERNETES_NAMESPACE);
+logger.debug('KUBERNETES_POD_NAME=' + process.env.KUBERNETES_POD_NAME);
+logger.debug('KUBERNETES_NODE_NAME=' + process.env.KUBERNETES_NODE_NAME);
+logger.debug('CONTAINER_IMAGE=' + process.env.CONTAINER_IMAGE);
 
 // Handlers
 
@@ -50,9 +63,10 @@ logger.debug('Serving from base path "' + handlerPathPrefix + '"');
 app.get(handlerPathPrefix + '/', function (req, res) {
     res.render('home', {
       message: message,
-      platform: os.type(),
-      release: os.release(),
-      hostName: os.hostname(),
+      namespace: namespace,
+      pod: podName,
+      node: nodeName + ' (' + nodeOS + ')',
+      container: containerImage + ' (' + containerImageArch + ')',
       renderPathPrefix: renderPathPrefix
     });
 });
@@ -64,5 +78,5 @@ logger.debug('Server');
 logger.debug('-----------------------------------------------------');
 
 app.listen(port, function () {
-  logger.info("Listening on: http://%s:%s", os.hostname(), port);
+  logger.info("Listening on: http://%s:%s", podName, port);
 });

src/app/server.js

@@ -15,6 +15,7 @@ div.main img {
 div.content {   
   color:#f2f2f2; 
 }
+
 .content #message {
   margin: 10px 0 50px 0;
   padding: 30px 0;  
@@ -26,6 +27,16 @@ div.content {
   border-bottom: 2px solid #909090;
 }
 
+.content #footer {
+  margin: 50px 0;
+  padding: 30px 0;  
+  font-family: 'Ubuntu', sans-serif;
+  font-weight: 300;
+  font-size: 12pt;
+  color: #909090;
+  border-top: 2px solid #909090;
+}
+
 .content #info {
   margin: 0 auto;
   font-family: 'Ubuntu', sans-serif;

src/app/static/css/main.css

@@ -3,14 +3,20 @@
 </div>
 <div id="info">
   <table>
+    <tr>
+      <th>namespace:</th>
+      <td>{{ namespace }}</td>
+    </tr>
     <tr>
       <th>pod:</th>
-      <td>{{ hostName }}</td>
+      <td>{{ pod }}</td>
     </tr>
     <tr>
       <th>node:</th>
-      <td>{{ platform }} ({{ release }})</td>
+      <td>{{ node }}</td>
     </tr>
   </table>
-
+</div>
+<div id="footer">
+  {{ container }}
 </div>