README
¶
Cats and Dogs
A sample app to demonstrate communication (HTTP and UDP) between a frontend and a backend application over the container network.
We're assuming that you've deployed to BOSH lite.
If you've deployed to AWS or another environment,
substitute bosh-lite.com below with the domain name of your installation.
To configure policies you use the CF CLI.
Frontend
The frontend serves a form at http://frontend.bosh-lite.com/.
The frontend allows you to test out container network communication via two methods:
- connect to the backend via HTTP
- connect to the backend via UDP
In either case, the response from the backend to the frontend will be rendered as a web page.
Deploying
cd cf-networking-release/src/example-apps/cats-and-dogs/frontend
cf api api.bosh-lite.com --skip-ssl-validation
cf auth admin admin
cf push frontend
Backend
The backend displays its container network IP if you visit http://backend.bosh-lite.com/.
The backend serves pictures of cats on the TCP ports specified in the environment variable CATS_PORTS,
and responds to simple text messages on the UDP ports specified in the environment variable UDP_PORTS.
Deploying
cd cf-networking-release/src/example-apps/cats-and-dogs/backend
cf push backend --no-start
cf set-env backend CATS_PORTS "7007,7008"
cf set-env backend UDP_PORTS "9003,9004"
cf start backend
Usage
After both frontend and backend apps have been deployed, you can visit http://backend.bosh-lite.com/
in a browser. You should see something like:
My overlay IP is: 10.255.76.2
I'm serving cats on TCP ports 7007,7008
I'm also serving a UDP echo server on UDP ports 9003,9004
If you were to visit http://frontend.bosh-lite.com, you should see something like:
Frontend Sample App
HTTP Test
Backend HTTP URL: [....] [ Submit ]
UDP Test
Backend UDP Server Address: [....]
Message: [....] [ Submit ]
Usage with HTTP
In Backend HTTP URL enter the backend's overlay IP and a cats port (10.255.76.2:7007).
Hit submit.
You will see an error message. This is because the two apps have not been configured to allow connections from the frontend to the backend.
Now allow access:
cf add-network-policy frontend --destination-app backend --port 7007 --protocol tcp
Now if you try again from the frontend:
[PICTURE OF CAT]
Hello from the backend, port: 7007
Usage with UDP
In Backend UDP Server Address enter the backend's overlay IP and UDP port
(10.255.76.2:9003) and a message. Hit submit.
You will see an error message. This is because the two apps have not been configured to allow connections from the frontend to the backend.
Now allow access:
cf add-network-policy frontend --destination-app backend --port 9003 --protocol udp
Now if you try again from the frontend:
You sent the message: hello world
Backend UDP server replied: HELLO WORLD
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