Meteor in production
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IN PRODUCTION
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Transcript of Meteor in production
IN PRODUCTION
Remco Veldkamp
★ Q42 - “happy place for nerds”
★ full-stack developer
★ worked on Rijksmuseum.nl
★ Meteor fan \o/
Q42 & Meteor
★ weekend hacks
★ prototypes
★ internal apps
★ …?
DemocratieLAB
★ “museum-tour”
★ 1 class of students at the time
★ tablet app guides student through museum
★ student answers questions on tablet
★ printed certificate at the end
Tablet app
Tech requirements
30 x Samsung G Tab
2
1 Windows pc
bad wifi :-(
recap
★ distributed application
★ robust w/r lossy network
This is a job for..
UX opportunities
realtime reactivity
‘Balie pc’ - teacher
Teacher - insert a new class
Classes = new Mongo.Collection(‘classes’);
Classes.insert({
location: "Aa en Hunze",
schoolType: "Basisonderwijs",
route: "42",
active: true
});
<button data-action=continue
class="fade {{#if activeClass}}visible{{/if}}">
ga verder
</button>
Template.player_welcome.helpers({
activeClass : function() {
return Classes.findOne({ active:true }); // livequery
}
});
Student view reacts
Realtime feedback
for free :-)
Realtime dashboard
Realtime dashboard
Teachers
★ instant feedback
about what’s going
on
★ more control: ability
to take action
Testing
Testing
★ end-to-end
★ the whole flow
★ real hardware
★ loadtest on location with real wifi conditions
Testing
one problem...
Autoplaytm
★ Hidden feature
behind debug flag
★ Accessible from
dashboard
Autoplaytm
Students.find(Session.get(‘studentId’)).observe({
changed: function(student) {
if (student.autoplay)
Meteor.setInterval(randomAnswer,
1000);
}
});
Performance under load
Requirements:
★ 30 tablets
★ pressing buttons every second
Autoplay!
Load test
Load test results
Latency compensation hides most of the delays
★ starting Tour was slow
★ circles in dashboard were lagging
Let’s investigate!
Load test results
Kadira
Arunoda Susiripala
Kadira: metrics
★ cpu usage
★ memory usage
★ pub/sub response time
★ method response time
Wait a minute..
Autopublish!
Solution
$ meteor remove autopublish
Solution
// server
Meteor.publish("studentById", function (id) {
return Students.find(id);
});
// client
Tracker.autorun(function() {
Meteor.subscribe("studentById", Session.get('studentId'));
});
±25ms
method response time
Conclusions
Conclusions
★ Real-time reactivity: UX opportunities
★ autopublish: use only for prototyping
★ latency compensation may hide problems
★ Kadira is a must-have
★ Meteor is ready for production
★ We’ll definitely be using it at Q42!
Conclusions
Q42.com
@remcoder
thx
