Envoy WASM filters with Gloo Edge
Support for Envoy WASM filters has been added to Gloo Edge Enterprise as of version 1.6.0+. This guide is specifically for Gloo Edge 1.6.0. Note, there may have been some changes to the configuration API since prior experimental versions.
This feature is considered to be in a tech preview state of stability. While wasm functionality has
been merged to upstream envoy, wasm filters are not yet recommended for production use. This tech preview
is meant to show off the potential of WASM filters, and how they will integrate with Gloo Edge going forward.
Envoy Wasm filters are a Gloo Edge Enterprise feature.
Configuration
Getting started with WASM is simple, first we install Gloo Edge Enterprise.
Gloo Edge Enterprise can be installed using either glooctl or helm 3 as follows:
glooctl install gateway enterprise --license-key YOUR_LICENSE_KEY
helm repo add gloo https://storage.googleapis.com/solo-public-helm
helm repo update
helm install gloo glooe/gloo-ee --namespace gloo-system \
--create-namespace --set-string license_key=YOUR_LICENSE_KEY
Once this process has been completed, gloo should be up and running in the gloo-system namespace.
To check run the following:
kubectl get pods -n gloo-system
NAME READY STATUS RESTARTS AGE
api-server-5b57f68dc-dqfjk 3/3 Running 0 77s
discovery-5ffdfb9898-js9j2 1/1 Running 0 77s
extauth-6888f56db4-kgz2n 1/1 Running 0 77s
gateway-569488695f-zpqnj 1/1 Running 0 77s
gateway-proxy-9c954dc8-wt46j 1/1 Running 0 77s
gloo-5984f6f655-ct97s 1/1 Running 0 77s
glooe-grafana-78c6f96db-qwnd2 1/1 Running 0 77s
glooe-prometheus-kube-state-metrics-7f8fd8dd8-cfmqp 1/1 Running 0 77s
glooe-prometheus-server-6cc865559b-gl8wq 2/2 Running 0 76s
observability-6dd56c8468-xvwqc 1/1 Running 0 77s
rate-limit-c4fb9fc5b-6gm4s 1/1 Running 0 76s
redis-55d6dbb6b7-fg7wm 1/1 Running 0 77s
Once all of the pods are up and running you are all ready to configure your first WASM filter. The API to configure the filter can be found here .
At the moment the config must live on the gateway level, this will change as the Envoy WASM api evolves. To configure a gateway to add a WASM filter, the gateway must be edited like so.
kubectl edit -n gloo-system gateways.gateway.solo.io gateway-proxy
and change the httpGateway object to the following:
httpGateway:
options:
wasm:
filters:
- config:
'@type': type.googleapis.com/google.protobuf.StringValue
value: "world"
image: webassemblyhub.io/sodman/example-filter:v0.5
name: myfilter
root_id: add_header_root_id
Once that is saved, the hard work has been done. All traffic on the http gateway will call the wasm filter.
If your image isn’t hosted on an image registry, such as WebAssembly Hub, you can load the filter from the wasm file directly instead:
httpGateway:
options:
wasm:
filters:
- config:
'@type': type.googleapis.com/google.protobuf.StringValue
value: "world"
filePath: filters-dir/my-filter.wasm
name: myfilter
root_id: add_header_root_id
When loading directly from file, you’ll need to ensure that the given filePath contains your .wasm file.
Loading a wasm filter image from an initContainer
In some circumstances, using WebAssembly Hub as your wasm filter image repository may not be possible, for example due to enterprise networking restrictions. One way to deploy a wasm filter without going through WebAssembly Hub, is to use an initContainer on your gatewayProxy deployment to load the .wasm file into a shared volume. This section will walk you through setting this up.
Prerequisites
We are assuming you already have a wasm filter created and built locally. You can replicate this by running the two commands below. Alternatively, you can follow the more in-depth guide in the WebAssembly Hub docs here.
wasme init --language cpp --platform gloo --platform-version 1.6.x ./my-filter
followed by
cd my-filter
wasme build cpp --store ./wasmstore . -t my-wasm-filter:v1.0
It’s also assumed that you have a k8s cluster running, with Gloo Edge Enterprise installed in it, ideally with a route to an upstream we can hit for testing. The example we’re using here uses Gloo Edge Enterprise 1.6.2, but any future version should work.
Step 1 - Build a docker image containing our filter
First we need to build a docker image which contains our new wasm filter image. In our steps above this file is called filter.wasm and has been output at .wasmstore/<uniqueId>/filter.wasm. If you’ve built your filter.wasm using a tool other than wasme, for example using bazel instead - the location of the filter file may differ. Let’s grab this filter.wasm file and put it in a folder somewhere that we can make changes.
We will create a file named Dockerfile as a sibling to this filter.wasm, this will be used to generate our docker image. The contents of Dockerfile should be as follows:
FROM alpine
COPY filter.wasm filter.wasm
CMD ["cp", "filter.wasm", "/wasm-filters/"]
This will create a basic docker image which just contains our filter.wasm file, and when run, will copy it to the /wasm-filters/ folder, which we will mount later.
Next we want to build and tag the docker image from this Dockerfile, by running the following command (replacing your repository URL, and preferred image name):
docker build . -t localhost:8888/myorg/my-wasm-getter:1.0.0
We have now created a standard docker image named localhost:8888/myorg/my-wasm-getter with a tag of 1.0.0. This can be pushed to whatever docker-compliant image repository you have:
docker push localhost:8888/myorg/my-wasm-getter:1.0.0
Step 2 - Add the initContainer to the gateway-proxy Deployment
Now that we have a docker image containing our wasm filter, we will use it as an initContainer for our gateway-proxy pod, so that the filter is available to Envoy via a shared mounted volume.
Update the gateway-proxy Deployment resource as shown below, noting the extra “wasm-filters” volume and volumeMount, as well as the addition of initContainers:
apiVersion: apps/v1
kind: Deployment
metadata:
name: gateway-proxy
namespace: gloo-system
spec:
selector:
matchLabels:
gateway-proxy-id: gateway-proxy
gloo: gateway-proxy
template:
metadata:
annotations:
prometheus.io/path: /metrics
prometheus.io/port: "8081"
prometheus.io/scrape: "true"
labels:
gateway-proxy: live
gateway-proxy-id: gateway-proxy
gloo: gateway-proxy
spec:
containers:
- args:
- --disable-hot-restart
env:
- name: POD_NAMESPACE
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.namespace
- name: POD_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.name
image: quay.io/solo-io/gloo-envoy-wrapper:1.6.2
imagePullPolicy: IfNotPresent
name: gateway-proxy
ports:
- containerPort: 8080
name: http
protocol: TCP
- containerPort: 8443
name: https
protocol: TCP
resources: {}
securityContext:
allowPrivilegeEscalation: false
capabilities:
drop:
- ALL
readOnlyRootFilesystem: true
runAsNonRoot: true
runAsUser: 10101
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /etc/envoy
name: envoy-config
- mountPath: /wasm-filters
name: wasm-filters
initContainers:
- name: wasm-image
image: localhost:8888/myorg/my-wasm-getter:1.0.0
imagePullPolicy: IfNotPresent
volumeMounts:
- mountPath: /wasm-filters
name: wasm-filters
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext:
fsGroup: 10101
runAsUser: 10101
serviceAccount: gateway-proxy
serviceAccountName: gateway-proxy
terminationGracePeriodSeconds: 30
volumes:
- configMap:
defaultMode: 420
name: gateway-proxy-envoy-config
name: envoy-config
- name: wasm-filtersWhat we’ve done here, is specify the initContainer, which will run before the gateway-proxy envoy starts up. It will add our filter.wasm file to the filepath at /wasm-filters/filter.wasm, and since that’s mounted to our gateway-proxy container, it’s now accessible to be read directly from the file.
Step 3 - Configure the wasm filter in the gateway
Now that the filter is in a filepath accessible to Envoy, we need to tell envoy to load it from path. We do this in the Gateway type resource, named gateway-proxy:
apiVersion: gateway.solo.io/v1
kind: Gateway
metadata:
labels:
app: gloo
app.kubernetes.io/managed-by: Helm
name: gateway-proxy
namespace: gloo-system
spec:
bindAddress: '::'
bindPort: 8080
httpGateway:
options:
wasm:
filters:
- config:
'@type': type.googleapis.com/google.protobuf.StringValue
value: "my test config"
filePath: /wasm-filters/filter.wasm
name: myfilter
root_id: add_header_root_id
proxyNames:
- gateway-proxy
ssl: false
useProxyProto: falseIf you’ve been following along with this example, you should now be able to curl one of your endpoints and see the results of your filter being run - in this case, a newly added http header. You can also confirm that the filter has been loaded by Envoy if you check the config_dump from the Envoy Admin page. This is usually served on port 19000:
kubectl port-forward -n gloo-system gateway-proxy-645bc75c67-xmfdz 19000:19000
When you open localhost:19000/config_dump, if you look under filter_chains you should see your deployed wasm filter with the name envoy.filters.http.wasm:
...
{
"name": "envoy.filters.http.wasm",
"typed_config": {
"@type": "type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm",
"config": {
"name": "myfilter",
"root_id": "add_header",
"vm_config": {
"vm_id": "gloo-vm-id",
"runtime": "envoy.wasm.runtime.v8",
"code": {
"remote": {
"http_uri": {
"uri": "http://gloo/images/8b3b05719379af3996d51bf6d5baed1103059fb908baec547f2136ed48aebd77",
"cluster": "wasm-cache",
"timeout": "5s"
},
"sha256": "8b3b05719379af3996d51bf6d5baed1103059fb908baec547f2136ed48aebd77"
}
},
"nack_on_code_cache_miss": true
},
"configuration": {
"@type": "type.googleapis.com/google.protobuf.StringValue",
"value": "my test config"
}
}
}
},
...
If you don’t have any test services to run against, you can install the petstore example used in our hello world tutorial.
References
To find our more information about WASM filters, and how to build/run them check out wasm.
In that repo you’ll find wasme, a tool for building and deploying Envoy WASM filters. wasme works with Gloo Edge Enterprise, Istio, and vanilla Envoy. Much more detailed information can be found there on how the filters work. Learn how to install the wasme CLI tool here.
To find more information about WASM filters, and find more filters which can be included in Gloo Edge check out WebAssembly Hub!.