Support cross-realm monitoring (#9)

Support connecting to multiple brokers and displaying all the devices on
a single graph.

This relies on cross-realm auth having been set up between the F+
instances.

.gitignore

@@ -14,6 +14,9 @@ public/webpack/
 /keytabs/
 /volumes/
 
+# Random tempdir
+/tmp/
+
 # IDE
 .idea/
 /public/output.css

public/index.html

@@ -36,8 +36,13 @@
           <input class="fpl-input" id="password" type="password" size="50">
         </label>
 
-        <div class="text-xs text-gray-400">These credentials will need to have global debugger rights to see much
-          of interest.
+        <div class="text-xs text-gray-400">
+            <p>These credentials will need to have global debugger
+            rights to see much of interest.
+            <p>To monitor multiple brokers at the same time, give a
+            space-separated list of Directory URLs. The username
+            will need to be the full Kerberos principal name of
+            an account with cross-realm access to all the brokers.
         </div>
 
         <label class="text-gray-500 font-medium flex items-center">

public/index.js

@@ -25,31 +25,45 @@ class FPlusVis {
         window.addEventListener("resize", resize);
         resize();
 
-        const fplus = await new FactoryPlus.ServiceClient({
-            directory_url:  opts.directory,
-            username:       opts.username,
-            password:       opts.password,
-            verbose:        "ALL",
-            browser:        true,
-        }).init();
-        window.AMRC_FactoryPlus_Vis_Client = fplus;
+        const graph = MQTTClient.graph("Factory+");
+        const clients = await this.build_clients(opts, graph);
+        this.clients = clients;
+        window.AMRC_FactoryPlus_Vis_Clients = clients;
+
+        const fplus = clients[0].fplus;
         const icons = await new Icons({ fplus }).init();
+        const vis = this.vis = new Vis(graph, canvas, icons);
+
+        vis.run();
+        for (const { mqtt } of clients) {
+            mqtt.on("packet", vis.make_active.bind(vis));
+            mqtt.on("graph", vis.reset_graph.bind(vis));
+            mqtt.on("schema", u => icons.request_icon(u));
+            mqtt.run();
+        }
+    }
 
-        const mqtt = this.mqtt = new MQTTClient({
-            fplus, icons,
-            name: "Factory+",
-        });
-        const vis = this.vis = new Vis(mqtt.graph, canvas, icons).run();
+    async build_clients (opts, graph) {
+        const directories = opts.directory.split(/\s+/);
+        const { username, password } = opts;
 
-        mqtt.on("packet", vis.make_active.bind(vis));
-        mqtt.on("graph", vis.reset_graph.bind(vis));
+        return Promise.all(directories.map(async directory_url => { 
+            const fplus = await new FactoryPlus.ServiceClient({
+                directory_url, username, password,
+                verbose:        "ALL",
+                browser:        true,
+            }).init();
+            const mqtt = new MQTTClient({ fplus, graph });
 
-        mqtt.run();
+            return { fplus, mqtt };
+        }));
     }
 
     async stop_vis () {
         await this.vis.stop();
-        await this.mqtt.stop();
+        for (const { mqtt } of this.clients) {
+            await mqtt.stop();
+        }
         this.canvas.style.display = "none";
     }
 

public/mqttclient.js

@@ -12,11 +12,14 @@ export default class MQTTClient extends EventEmitter {
     constructor (opts) {
         super();
         this.fplus = opts.fplus;
-        this.icons = opts.icons;
+        this.graph = opts.graph;
 
         this.known = new Map();
-        this.graph = {
-            name: opts.name,
+    }
+
+    static graph (name) {
+        return {
+            name,
             online: true,
         };
     }
@@ -35,6 +38,7 @@ export default class MQTTClient extends EventEmitter {
 
     stop () {
         clearInterval(this.expiry_timer);
+        if (!this.mqtt) return;
         return new Promise((resolve, reject) => {
             this.mqtt.on("end", resolve);
             this.mqtt.end();
@@ -116,7 +120,7 @@ export default class MQTTClient extends EventEmitter {
 
         //console.log("Found schema %s for %s", schema, node.name);
         node.schema = schema;
-        this.icons.request_icon(schema);
+        this.emit("schema", schema);
     }
 
     async check_directory (address, node) {
@@ -134,7 +138,7 @@ export default class MQTTClient extends EventEmitter {
         if (node.seen_birth) return;
 
         node.schema = info.top_schema;
-        this.icons.request_icon(node.schema);
+        this.emit("schema", node.schema);
     }
 
     on_expiry () {