You can use envoy filter to do that.
Below envoy filter add request header called customer-id with alice value to all request going though istio ingress gateway. I also commented code for response headers if someone would like to use it.
apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
name: lua-filter
namespace: istio-system
spec:
workloadSelector:
labels:
istio: ingressgateway
configPatches:
- applyTo: HTTP_FILTER
match:
context: GATEWAY
listener:
filterChain:
filter:
name: "envoy.http_connection_manager"
subFilter:
name: "envoy.router"
patch:
operation: INSERT_BEFORE
value:
name: envoy.lua
typed_config:
"@type": "type.googleapis.com/envoy.config.filter.http.lua.v2.Lua"
inlineCode: |
function envoy_on_request(request_handle)
request_handle:headers():add("customer-id", "alice")
end
# function envoy_on_response(response_handle)
# response_handle:headers():add("customer-id", "alice")
# end
There are yamls I've used to test that, it might be useful for testing above filter.
- If you use above filter with alice header then all requests goes to nginx-v1
- If you use above filter with bob header then all requests goes to nginx-v2
- If you delete this filter then it's 50/50 between nginx-v1 and nginx-v2
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-v1
spec:
selector:
matchLabels:
run: nginx1
replicas: 1
template:
metadata:
labels:
run: nginx1
app: frontend
spec:
containers:
- name: nginx1
image: nginx
ports:
- containerPort: 80
lifecycle:
postStart:
exec:
command: ["/bin/sh", "-c", "echo Hello nginx1 > /usr/share/nginx/html/index.html"]
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-v2
spec:
selector:
matchLabels:
run: nginx2
replicas: 1
template:
metadata:
labels:
run: nginx2
app: frontend
spec:
containers:
- name: nginx2
image: nginx
ports:
- containerPort: 80
lifecycle:
postStart:
exec:
command: ["/bin/sh", "-c", "echo Hello nginx2 > /usr/share/nginx/html/index.html"]
---
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: frontend
spec:
ports:
- name: http-front
port: 80
protocol: TCP
selector:
app: frontend
---
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: gatewayx
spec:
selector:
istio: ingressgateway # use istio default controller
servers:
- port:
number: 80
name: http
protocol: HTTP
hosts:
- "*"
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: nginxvirt
spec:
hosts:
- '*'
gateways:
- gatewayx
http:
- name: "route-1"
match:
- headers:
customer-id:
exact: alice
route:
- destination:
host: nginx
subset: v1
- name: "route-2"
match:
- headers:
customer-id:
exact: bob
route:
- destination:
host: nginx
subset: v2
- route:
- destination:
host: nginx
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
name: nginxdest
spec:
host: nginx
subsets:
- name: v1
labels:
run: nginx1
- name: v2
labels:
run: nginx2
