Improve the Ubuntu Server linkbot monitoring

Changelog: None
Signed-off-by: Ole Petter <ole.orhagen@northern.tech>

scripts/linkbot/monitor-ub-server.js

@@ -3,6 +3,7 @@ const { JSDOM } = jsdom;
 const fs = require('fs')
 const { updateURLLink } = require('./common');
 
+const target = "UBUNTU_SERVER_RPI_IMAGE_URL"
 const url = "http://cdimage.ubuntu.com/ubuntu/releases/"
 const reg = ".*(?<release>[0-9]{2})\.04\.?(?<minor>[0-9]{1})?.*"
 
@@ -10,7 +11,7 @@ const reg = ".*(?<release>[0-9]{2})\.04\.?(?<minor>[0-9]{1})?.*"
 try {
     const data = fs.readFileSync('../test/run-tests.sh', 'utf8')
           .split('\n')
-          .filter(line => line.match("UBUNTU_SERVER_RPI_IMAGE_URL=.*"))
+          .filter(line => line.match(`${target}=.*`))
     var line = data[0]
     var m = line.match(`.*=\"${reg}\"`)
     var imageName = m.groups.release
@@ -33,14 +34,20 @@ JSDOM.fromURL(url, {}).then(dom => {
             return parseInt(b.groups.release) - parseInt(a.groups.release) || parseFloat(b.groups.minor) - parseFloat(a.groups.minor)
         })
     var matchOn = matches[0].input
-    if (matchOn !== imageName) {
-        console.log("We've got a new release! \\o/");
-        var newLine = ""
-        if (matches[0].groups.minor) {
-            newLine = `UBUNTU_SERVER_RPI_IMAGE_URL=\"${url}${matches[0].groups.release}.04.${matches[0].groups.minor}/release/ubuntu-${matches[0].groups.release}.04.${matches[0].groups.minor}-preinstalled-server-armhf+raspi.img.xz\"`
-        } else {
-            newLine = `UBUNTU_SERVER_RPI_IMAGE_URL=\"${url}${matches[0].groups.release}.04/release/ubuntu-${matches[0].groups.release}.04-preinstalled-server-armhf+raspi.img.xz\"`
+
+    return matchOn;
+
+    // Get the release image url from the releases (sub)-page
+    // const url = "http://cdimage.ubuntu.com/ubuntu/releases/"
+}).then(releaseVersion => {
+    var releaseVersion = releaseVersion.replace(/\s/g, "").replace(/\//g, "")
+    JSDOM.fromURL(`${url}${releaseVersion}/release/`, {}).then(dom => {
+        var document = dom.window.document;
+        var refs = document.getElementsByTagName("a");
+        const match = Array.from(refs).find(ref => ref.href.match(`.*ubuntu-${releaseVersion}-preinstalled-server-armhf.*\.img\.xz$`))
+        if (match) {
+            console.log(`Ubuntu server image has a new release: ${match}`)
+            updateURLLink(`${target}=${match}`, target)
         }
-        updateURLLink(newLine)
-    }
+    })
 });