Test the App on App Mesh

We now have both App Mesh and the application deployed. Next comes the fun part of seeing how we can use App Mesh to change the charactertics of the application.

Open Two Terminals

You should already have one terminal open. Click the widget on the Cloud9 GUI and open a second terminal.

Use curler to fetch the application response

In the first terminal, run the following command to connect to the curler pod with a bash shell (you may be prompted to hit enter to get a command line prompt):

kubectl run -it curler --image=tutum/curl /bin/bash

Next, with a shell open to the curler pod, paste the following to repeatedly request the colorgateway service:

while [ 1 ]; do  curl -s --connect-timeout 2 http://colorgateway.default.svc.cluster.local:9080/color;echo;sleep 1; done

Every second, you should see the response white.

This is because colorgateway always forwards to colorteller, which via the colorteller-route, always routes to colorteller-vn (which will always respond with white).

Let’s modify the colorteller-route so it instead routes to the blue, red, and black colorteller virtual nodes, each at a 30% weighted ratio.

Modify colorteller-route

To modify colorteller-route, copy and paste the following into the other terminal (the one that is not making the curl requests):

aws appmesh update-route  --mesh-name APP_MESH_DEMO --cli-input-json '{
    "routeName": "colorteller-route",
    "spec": {
        "httpRoute": {
            "action": {
                "weightedTargets": [
                    {
                            "virtualNode": "colorteller-blue-vn",
                            "weight": 3
                        },
                        {
                            "virtualNode": "colorteller-red-vn",
                            "weight": 3
                        },
                        {
                            "virtualNode": "colorteller-black-vn",
                            "weight": 3
                        }
                ]
            },
            "match": {
                "prefix": "/"
            }
        }
    },
    "virtualRouterName": "colorteller-vr"
}'

If you look at the curler terminal, you should now see an equal distribution of traffic to the blue, red, and black virtual nodes.

For fun, to see a 50⁄50 weighted response of only the red and black virtual nodes, copy and paste the following route:

aws appmesh update-route  --mesh-name APP_MESH_DEMO --cli-input-json '{
    "routeName": "colorteller-route",
    "spec": {
        "httpRoute": {
            "action": {
                "weightedTargets": [
                        {
                            "virtualNode": "colorteller-red-vn",
                            "weight": 5
                        },
                        {
                            "virtualNode": "colorteller-black-vn",
                            "weight": 5
                        }
                ]
            },
            "match": {
                "prefix": "/"
            }
        }
    },
    "virtualRouterName": "colorteller-vr"
}'