WASM Extension

The WASM extension resource allows defining custom WASM extensions that are packaged in OCI images. The resource allows specifying extension metadata that helps understand how extensions work and how they can be used. Once defined, extensions can be referenced in Ingress and Egress Gateways and Security Groups so that traffic is captured and processed by the extension accordingly. By default, extensions are globally available, but they can be assigned to specific Tenants as well to further control and constraint where in the Organization the extensions are allowed to be used.

apiVersion: extension.tsb.tetrate.io/v2
kind: WasmExtension
metadata:
  organization: org
  name: wasm-auth
spec:
  allowedIn:
    - organizations/org/tenants/tenant1
  image: oci://docker.io/example/my-wasm-extension:1.0
  source: https://github.com/example/wasm-extension
  description: |
    Long description for the extension such as an
    entire README file
  phase: AUTHZ
  priority: 1000
  config:
    some_key: some_value

EnvValueSource

Name	Number	Description
INLINE	0	Explicitly given key-value pairs to be injected to this VM.
HOST	1	Istio-proxy's* environment variables exposed to this VM.

EnvVar

Field	Description	Validation Rule
name	string REQUIRED Name of the environment variable. Must be a CIDENTIFIER, by following this regex: [A-Za-z][A-Za-z0-9_]*	string = {   pattern: [A-Za-z_][A-Za-z0-9_]* }
valueFrom	tetrateio.api.tsb.extension.v2.EnvValueSource REQUIRED Source for the environment variable's value.	enum = {   defined_only: true }
value	string Value for the environment variable. Note that if value_from is HOST, it will be ignored. Defaults to "".	–

VmConfig

Configuration for a Wasm VM. more details can be found here.

Field	Description	Validation Rule
env	List of tetrateio.api.tsb.extension.v2.EnvVar Specifies environment variables to be injected to this VM. Note that if a key does not exist, it will be ignored.	–

WasmExtension

Field	Description	Validation Rule
allowedIn	List of string List of fqns where this extension is allowed to run. If it is empty, the extension can be used across the entire organization. Currently only Tenant resources are considered.	repeated = {   items: {string:{min_len:1}} }
image	string REQUIRED Repository and tag of the OCI image containing the WASM extension.	string = {   prefix: oci:// }
source	string Source to find the code for the WASM extension	–
phase	tetrateio.api.tsb.extension.v2.WasmExtension.PluginPhase The phase in the filter chain where the extension will be injected. https://istio.io/latest/docs/reference/config/proxy_extensions/wasm-plugin/#PluginPhase	enum = {   defined_only: true }
priority	int32 Determines the ordering of WasmExtensions in the same phase. When multiple WasmExtensions are applied to the same workload in the same phase, they will be applied by priority, in descending order. If no priority is assigned it will use the default 0 value. In case of several extensions having the same priority in the same phase, the fqn will be used to sort them.	–
config	google.protobuf.Struct Configuration parameters sent to the WASM plugin execution The configuration can be overwritten when instantiating the extensions in IngressGateways or Security groups. The config is serialized using proto3 JSON marshaling and passed to proxy_on_configure when the host environment starts the plugin.	–
imagePullPolicy	tetrateio.api.tsb.extension.v2.WasmExtension.PullPolicy The pull behaviour to be applied when fetching Wasm module by either OCI image or http/https. Only relevant when referencing Wasm module without any digest, including the digest in OCI image URL or sha256 field in vm_config. Defaults to IfNotPresent, except when an OCI image is referenced in the url and the latest tag is used, in which case Always is the default, mirroring K8s behaviour.	enum = {   defined_only: true }
imagePullSecret	string Credentials to use for OCI image pulling. Name of a K8s Secret in the same namespace as the WasmPlugin that contains a docker pull secret which is to be used to authenticate against the registry when pulling the image.	–
vmConfig	tetrateio.api.tsb.extension.v2.VmConfig VM Configuration sent to the WASM plugin execution	–

PluginPhase

Plugin phases following Istio definition: https://istio.io/latest/docs/reference/config/proxy_extensions/wasm-plugin/#PluginPhase

Name	Number	Description
UNSPECIFIED_PHASE	0	Control plane decides where to insert the plugin. This will generally be at the end of the filter chain, right before the Router. Do not specify PluginPhase if the plugin is independent of others.
AUTHN	1	Insert plugin before Istio authentication filters.
AUTHZ	2	Insert plugin before Istio authorization filters and after Istio authentication filters.
STATS	3	Insert plugin before Istio stats filters and after Istio authorization filters.

PullPolicy

The pull behaviour to be applied when fetching a WASM module, mirroring K8s behaviour.

Name	Number	Description
UNSPECIFIED_POLICY	0	Defaults to IfNotPresent, except for OCI images with tag latest, for which the default will be Always.
IfNotPresent	1	If an existing version of the image has been pulled before, that will be used. If no version of the image is present locally, we will pull the latest version.
Always	2	We will always pull the latest version of an image when changing this plugin. Note that the change includes metadata field as well.