Prevent live view viewers from making openQA unresponsive

* Avoid live view viewers from occupying too many Mojolicious workers by
  moving the image streaming of the live mode to the live handler daemon
* Make sure the frontend code can still connect to the streaming route in a
  development setup by taking the different port into account and by
  setting CORS headers
* Tested by running the main web UI service allowing only a limited number
  of connections via `script/openqa prefork -c 1 -w 1`. This causes it to
  be unresponsive if there is at least one live view tab open. With this
  change this is no longer a problem and multiple live tabs can be opened
  and are updated simultaneously.
* Tested without and with reverse proxy.

assets/javascripts/openqa.js

@@ -121,24 +121,34 @@ function reloadPage() {
   location.reload();
 }
 
-// returns an absolute "ws://" URL for the specified URL which might be relative
-function makeWsUrlAbsolute(url, servicePortDelta) {
-  // don't adjust URLs which are already absolute
-  if (url.indexOf('ws:') === 0) {
-    return url;
-  }
-
-  // read port from the page's current URL
-  var location = window.location;
-  var port = Number.parseInt(location.port);
+function makeUrlPort(servicePortDelta) {
+  // read port from the location of the current page
+  let port = Number.parseInt(window.location.port);
   if (Number.isNaN(port)) {
     // don't put a port in the URL if there's no explicit port
     port = '';
   } else {
     if (port !== 80 || port !== 443) port += servicePortDelta;
     port = ':' + port;
   }
+  return port;
+}
+
+function makeUrlAbsolute(url, servicePortDelta) {
+  const location = window.location;
+  const port = makeUrlPort(servicePortDelta);
+  return location.protocol + '//' + location.hostname + port + (url.indexOf('/') !== 0 ? '/' : '') + url;
+}
+
+// returns an absolute "ws://" URL for the specified URL which might be relative
+function makeWsUrlAbsolute(url, servicePortDelta) {
+  // don't adjust URLs which are already absolute
+  if (url.indexOf('ws:') === 0) {
+    return url;
+  }
 
+  const location = window.location;
+  const port = makeUrlPort(servicePortDelta);
   return (
     (location.protocol == 'https:' ? 'wss://' : 'ws:/') +
     location.hostname +

assets/javascripts/running.js

@@ -221,7 +221,7 @@ function addDataListener(elem, callback) {
   // ensure any previously added event source is removed
   removeDataListener(elem);
 
-  // define callback function for response of OpenQA::WebAPI::Controller::Running::streamtext
+  // define callback function for response of OpenQA::Shared::Controller::Running::streamtext
   if (!elem.eventCallback) {
     elem.eventCallback = function (event) {
       // define max size of the live log
@@ -241,7 +241,7 @@ function addDataListener(elem, callback) {
         var catData = currentData + newData;
         var newStartIndex = newLength - maxLiveLogLength;
 
-        // discard one (probably) partial line (in accordance with OpenQA::WebAPI::Controller::Running::streamtext)
+        // discard one (probably) partial line (in accordance with OpenQA::Shared::Controller::Running::streamtext)
         for (; newStartIndex < catData.length && catData[newStartIndex] !== '\n'; ++newStartIndex);
 
         firstElement.innerHTML = catData.substr(newStartIndex);
@@ -309,13 +309,13 @@ var last_event;
 
 // loads a data-url img into a canvas
 function loadCanvas(canvas, dataURL) {
-  var context = canvas[0].getContext('2d');
+  var context = canvas.getContext('2d');
 
   // load image from data url
   var scrn = new Image();
   scrn.onload = function () {
-    canvas[0].width = this.width;
-    canvas[0].height = this.height;
+    canvas.width = this.width;
+    canvas.height = this.height;
     context.clearRect(0, 0, this.width, this.width);
     context.drawImage(this, 0, 0);
   };
@@ -324,12 +324,16 @@ function loadCanvas(canvas, dataURL) {
 
 function initLivestream() {
   // setup callback for livestream
-  var livestream = $('#livestream');
-  livestream.eventCallback = function (event) {
+  const livestream = document.getElementById('livestream');
+  const servicePortDelta = Number.parseInt(document.getElementById('developer-panel').dataset.servicePortDelta);
+  const url = makeUrlAbsolute(livestream.dataset.url, servicePortDelta);
+  livestream.dataset.url = url;
+  const elements = $(livestream);
+  elements.eventCallback = function (event) {
     loadCanvas(livestream, event.data);
     last_event = event;
   };
-  liveViewElements.push({log: livestream});
+  liveViewElements.push({log: elements});
 }
 
 function disableLivestream() {
@@ -1125,7 +1129,7 @@ function processWsCommand(obj) {
     case 'error':
       // handle errors
 
-      // ignore connection errors if there's no running module according to OpenQA::WebAPI::Controller::Running::status
+      // ignore connection errors if there's no running module according to OpenQA::Shared::Controller::Running::status
       // or the test execution is stopped
       if ((!testStatus.running || developerMode.stoppingTestExecution) && category === 'cmdsrv-connection') {
         console.log('ignoring error from ws proxy: ' + what);

lib/OpenQA/LiveHandler.pm

@@ -7,6 +7,7 @@ use Mojo::Base 'Mojolicious', -signatures;
 use OpenQA::Schema;
 use OpenQA::Log 'setup_log';
 use OpenQA::Setup;
+use OpenQA::Utils qw(service_port);
 
 has secrets => sub { shift->schema->read_application_secrets };
 
@@ -56,6 +57,9 @@ sub startup ($self) {
     $job_r->post('/upload_progress')->name('developer_post_upload_progress')
       ->to('live_view_handler#post_upload_progress');
 
+    # register route for live streaming of image
+    $test_r->get('/streaming')->name('streaming')->to('running#streaming');
+
     OpenQA::Setup::setup_plain_exception_handler($self);
 }
 

lib/OpenQA/WebAPI/Controller/Running.pm → lib/OpenQA/Shared/Controller/Running.pm

@@ -1,7 +1,7 @@
 # Copyright 2014-2021 SUSE LLC
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-package OpenQA::WebAPI::Controller::Running;
+package OpenQA::Shared::Controller::Running;
 use Mojo::Base 'Mojolicious::Controller', -signatures;
 
 use Mojo::Util 'b64_encode';
@@ -178,8 +178,16 @@ sub streaming ($self) {
     $self->render_later;
     Mojo::IOLoop->stream($self->tx->connection)->timeout(900);
     my $res = $self->res;
+    my $headers = $res->headers;
     $res->code(200);
-    $res->headers->content_type('text/event-stream');
+    $headers->content_type('text/event-stream');
+
+    # set CORS headers required when not using a reverse proxy (so the port differs)
+    if ($self->is_local_request) {
+        my $req_origin = $self->req->url->base->clone->port(undef);
+        $headers->append(Vary => 'Origin');
+        $headers->access_control_allow_origin("$req_origin:" . service_port('webui'));
+    }
 
     # setup a function to stop streaming again
     my $timer_id;

t/26-controllerrunning.t

@@ -14,7 +14,7 @@ use lib "$FindBin::Bin/lib", "$FindBin::Bin/../external/os-autoinst-common/lib";
 use DateTime;
 use Test::Warnings ':report_warnings';
 use OpenQA::Test::TimeLimit '6';
-use OpenQA::WebAPI::Controller::Running;
+use OpenQA::Shared::Controller::Running;
 use OpenQA::Jobs::Constants;
 use Test::MockModule;
 use Test::Output qw(combined_is combined_like);
@@ -59,7 +59,7 @@ subtest streaming => sub {
     $id = Mojo::IOLoop->stream($stream);
     my $log = Mojo::Log->new;
     my $contapp = Mojolicious->new(log => $log);
-    my $controller = OpenQA::WebAPI::Controller::Running->new(app => $contapp);
+    my $controller = OpenQA::Shared::Controller::Running->new(app => $contapp);
     my $faketx = Mojo::Transaction::Fake->new(fakestream => $id);
     $log->unsubscribe('message');
     $log->on(message => sub { my ($log, $level, @lines) = @_; $log_messages .= join "\n", @lines, '' });
@@ -89,7 +89,7 @@ subtest streaming => sub {
 
     # test image streaming
     $contapp->attr(schema => sub { FakeSchema->new() });
-    $controller = OpenQA::WebAPI::Controller::Running->new(app => $contapp);
+    $controller = OpenQA::Shared::Controller::Running->new(app => $contapp);
     $faketx = Mojo::Transaction::Fake->new(fakestream => $id);
     $controller->tx($faketx);
     monkey_patch 'FakeSchema::Find', find => sub { Job->new };
@@ -122,13 +122,13 @@ subtest init => sub {
     my $not_found;
     my $render_specific_not_found;
     my $render;
-    monkey_patch 'OpenQA::WebAPI::Controller::Running', not_found => sub { $not_found = 1 };
-    monkey_patch 'OpenQA::WebAPI::Controller::Running',
+    monkey_patch 'OpenQA::Shared::Controller::Running', not_found => sub { $not_found = 1 };
+    monkey_patch 'OpenQA::Shared::Controller::Running',
       render_specific_not_found => sub { $render_specific_not_found = 1 };
-    monkey_patch 'OpenQA::WebAPI::Controller::Running', reply => sub { shift };
-    monkey_patch 'OpenQA::WebAPI::Controller::Running', render => sub { shift; $render = [@_] };
+    monkey_patch 'OpenQA::Shared::Controller::Running', reply => sub { shift };
+    monkey_patch 'OpenQA::Shared::Controller::Running', render => sub { shift; $render = [@_] };
 
-    my $c = OpenQA::WebAPI::Controller::Running->new(app => $app);
+    my $c = OpenQA::Shared::Controller::Running->new(app => $app);
     $c->param(testid => 'foobar');
 
     # No job could be found
@@ -170,15 +170,15 @@ subtest edit => sub {
     my $not_found;
     my $render_specific_not_found;
     my $found;
-    monkey_patch 'OpenQA::WebAPI::Controller::Running', init => sub { 1 };
+    monkey_patch 'OpenQA::Shared::Controller::Running', init => sub { 1 };
     monkey_patch 'FakeSchema::Find', find => sub { undef };
-    monkey_patch 'OpenQA::WebAPI::Controller::Running', not_found => sub { $not_found = 1 };
-    monkey_patch 'OpenQA::WebAPI::Controller::Running',
+    monkey_patch 'OpenQA::Shared::Controller::Running', not_found => sub { $not_found = 1 };
+    monkey_patch 'OpenQA::Shared::Controller::Running',
       render_specific_not_found => sub { $render_specific_not_found = 1 };
-    monkey_patch 'OpenQA::WebAPI::Controller::Running', reply => sub { shift };
+    monkey_patch 'OpenQA::Shared::Controller::Running', reply => sub { shift };
 
     # No results
-    my $c = OpenQA::WebAPI::Controller::Running->new(app => $app);
+    my $c = OpenQA::Shared::Controller::Running->new(app => $app);
     $c->param('testid', "foobar");
     $c->stash("job", Job->new);
     $c->edit();
@@ -187,8 +187,8 @@ subtest edit => sub {
     # Check if we can get the fake results
     my $details_count;
     monkey_patch 'FakeSchema::Find', find => sub { Job->new };
-    monkey_patch 'OpenQA::WebAPI::Controller::Running', redirect_to => sub { $found = 1; $details_count = $_[5]; };
-    $c = OpenQA::WebAPI::Controller::Running->new(app => $app);
+    monkey_patch 'OpenQA::Shared::Controller::Running', redirect_to => sub { $found = 1; $details_count = $_[5]; };
+    $c = OpenQA::Shared::Controller::Running->new(app => $app);
     $c->param('testid', "foobar");
     $c->stash("job", Job->new);
     $c->edit();

templates/webapi/test/live.html.ep

@@ -193,7 +193,7 @@
 </div>
 
 <div id="canholder">
-  <canvas id="livestream" width="1024" height="768" data-url='<%= url_for("streaming", testid => $testid) %>'>
+  <canvas id="livestream" width="1024" height="768" data-url="/liveviewhandler/tests/<%= $testid %>/streaming">
   </canvas>
 </div>