atmosphere-2013-talk
It's HTTP, All The Way Down
Wes Mason
Who?
- @1stvamp (twitter/github)
- Engineer at ServerDensity
- I release lots of open source code
- Curate phpweekly.info
Hyperwhat?
- First version of HTTP implemented by Tim Berners-Lee in 1991
- Expanded by the HTTP WG in '95.
- Very little has changed in 22 years.
No really, what?
- Very simple text based protocol
- First part contains metadata (headers)
- Resource centric actions
- Body can contain any kind of encoded data
What's new?
- HTTP/1.1 (1999) adds some sugar
- New new:
- Server Sent Events
- WebSockets
- New protocols:
- SPDY
- HTTP/2
A little about our architecture
- Service Orientated
- Each service in it's own codebase
- HTTP APIs
- Their own clusters with load balancers
Our services
- RESTful
- Stateless
- Mostly thinlayers
- Common documented API
- Callable from frontend
The web is our API
- Everything does HTTP
- REST is great - let's do more of this
- Almost everything can do HTTP asynchronously
Brave New (Async) World
- Longpolling, WebSockets and Server Sent Events
- UIs are responsive or go home
- Libraries like socket.io and SockJS make this pretty easy for devs
Asynchronous?
Services
- Non-blocking IO
- Both client and server
- Multiple "workers" - scaling
Frontend
- Several things
- Not polling for updates, "real time"
- Performing backend tasks without blocking the UI
- WebWorkers
In which Jane clicks a button
$('.button').click(function() {
$.ajax(...);
});
GET /svc/users/:id Cookie: session=blah Content-Type: application/json Accept: ...
<your application code here>
Content-Type: application/json
Content-Length: 14
X-Barium: foobar
Connection: close
{"foo": "baz"}
Sockii
- Multiple backend servers
- JavaScript powered frontend
- Authentication/Authorisation?
- Routing?
- Cross domain?
Add a little barium
- Every external request coming in via sockii gets an X-Barium header
- Our client libraries add this header for internal requests
- "Unique" ID (UUID-4)
- Logged
- A single payload going through our alerting system will maintain this ID
- We can query for records matching it
Skyhooks
- Many tasks running in a cluster, e.g. polling AWS or Rackspace
- Need to get a response back from a task to a connected WebSocket
- Webhooks to the rescue!
# import requests, import pymongo
# setup collection etc. etc.
hooks = webhook_collection.find({"account_id": id})
if data and len(data) > 0:
for hook in hooks:
requests.post(hook["url"], data)
sys.exit(0)
^D
- Jonathan "Joff" Oliver: about.me/joffie
- Grab me and say hi :-)