228 lines
7.7 KiB
Plaintext
228 lines
7.7 KiB
Plaintext
---
|
|
layout: docs
|
|
page_title: Lua Envoy Extension
|
|
description: >-
|
|
Learn how the `lua` Envoy extension enables Consul to run Lua scripts during Envoy requests and responses from Consul-generated Envoy resources.
|
|
---
|
|
|
|
# Run Lua scripts in Envoy proxy
|
|
|
|
The Lua Envoy extension enables the [HTTP Lua filter](https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_filters/lua_filter) in your Consul Envoy proxies, letting you run Lua scripts when requests and responses pass through Consul-generated Envoy resources.
|
|
|
|
Envoy filters support setting and getting dynamic metadata, allowing a filter to share state information with subsequent filters. To set dynamic metadata, configure the HTTP Lua filter. Users can call `streamInfo:dynamicMetadata()` from Lua scripts to get the request's dynamic metadata.
|
|
|
|
## Configuration specifications
|
|
|
|
To use the Lua Envoy extension, configure the following arguments in the `EnvoyExtensions` block:
|
|
|
|
| Arguments | Description |
|
|
| -------------- | ------------------------------------------------------------------------------------------------ |
|
|
| `ProxyType` | Determines the proxy type the extension applies to. The only supported value is `connect-proxy`. |
|
|
| `ListenerType` | Specifies if the extension is applied to the `inbound` or `outbound` listener. |
|
|
| `Script` | The Lua script that is configured to run by the HTTP Lua filter. |
|
|
|
|
## Workflow
|
|
|
|
There are two steps to configure the Lua Envoy extension:
|
|
|
|
1. Configure EnvoyExtensions through `service-defaults` or `proxy-defaults`.
|
|
1. Apply the configuration entry.
|
|
|
|
### Configure `EnvoyExtensions`
|
|
|
|
To use Envoy extensions, you must configure and apply a `proxy-defaults` or `service-defaults` configuration entry with the Envoy extension.
|
|
|
|
- When you configure Envoy extensions on `proxy-defaults`, they apply to every service.
|
|
- When you configure Envoy extensions on `service-defaults`, they apply to a specific service.
|
|
|
|
Consul applies Envoy extensions configured in `proxy-defaults` before it applies extensions in `service-defaults`. As a result, the Envoy extension configuration in `service-defaults` may override configurations in `proxy-defaults`.
|
|
|
|
The following example configures the Lua Envoy extension on every service by using the `proxy-defaults`.
|
|
|
|
<Tabs>
|
|
<Tab heading="HCL" group="hcl">
|
|
<CodeBlockConfig filename="lua-envoy-extension-proxy-defaults.hcl">
|
|
|
|
```hcl
|
|
Kind = "proxy-defaults"
|
|
Name = "global"
|
|
Protocol = "http"
|
|
EnvoyExtensions {
|
|
Name = "builtin/lua"
|
|
|
|
Arguments = {
|
|
ProxyType = "connect-proxy"
|
|
Listener = "inbound"
|
|
Script = <<-EOS
|
|
function envoy_on_request(request_handle)
|
|
meta = request_handle:streamInfo():dynamicMetadata()
|
|
m = meta:get("consul")
|
|
request_handle:headers():add("x-consul-service", m["service"])
|
|
request_handle:headers():add("x-consul-namespace", m["namespace"])
|
|
request_handle:headers():add("x-consul-datacenter", m["datacenter"])
|
|
request_handle:headers():add("x-consul-trust-domain", m["trust-domain"])
|
|
end
|
|
EOS
|
|
}
|
|
}
|
|
```
|
|
|
|
</CodeBlockConfig>
|
|
</Tab>
|
|
<Tab heading="JSON" group="json">
|
|
<CodeBlockConfig filename="lua-envoy-extension-proxy-defaults.json">
|
|
|
|
```hcl
|
|
{
|
|
"kind": "proxy-defaults",
|
|
"name": "global",
|
|
"protocol": "http",
|
|
"envoy_extensions": [{
|
|
"name": "builtin/lua",
|
|
"arguments": {
|
|
"proxy_type": "connect-proxy",
|
|
"listener": "inbound",
|
|
"script": "function envoy_on_request(request_handle)\nmeta = request_handle:streamInfo():dynamicMetadata()\nm = \nmeta:get("consul")\nrequest_handle:headers():add("x-consul-service", m["service"])\nrequest_handle:headers():add("x-consul-namespace", m["namespace"])\nrequest_handle:headers():add("x-consul-datacenter", m["datacenter"])\nrequest_handle:headers():add("x-consul-trust-domain", m["trust-domain"])\nend"
|
|
}
|
|
}]
|
|
}
|
|
```
|
|
|
|
</CodeBlockConfig>
|
|
</Tab>
|
|
<Tab heading="Kubernetes" group="kubernetes">
|
|
<CodeBlockConfig filename="lua-envoy-extension-proxy-defaults.yaml">
|
|
|
|
```yaml
|
|
apiVersion: consul.hashicorp.com/v1alpha1
|
|
kind: ProxyDefaults
|
|
metadata:
|
|
name: global
|
|
spec:
|
|
protocol: http
|
|
envoyExtensions:
|
|
name = "builtin/lua"
|
|
arguments:
|
|
proxyType: "connect-proxy"
|
|
listener: "inbound"
|
|
script: |-
|
|
function envoy_on_request(request_handle)
|
|
meta = request_handle:streamInfo():dynamicMetadata()
|
|
m = meta:get("consul")
|
|
request_handle:headers():add("x-consul-service", m["service"])
|
|
request_handle:headers():add("x-consul-namespace", m["namespace"])
|
|
request_handle:headers():add("x-consul-datacenter", m["datacenter"])
|
|
request_handle:headers():add("x-consul-trust-domain", m["trust-domain"])
|
|
end
|
|
```
|
|
|
|
</CodeBlockConfig>
|
|
</Tab>
|
|
</Tabs>
|
|
|
|
For a full list of parameters for `EnvoyExtensions`, refer to the [`service-defaults`](/consul/docs/connect/config-entries/service-defaults#envoyextensions) and [`proxy-defaults`](/consul/docs/connect/config-entries/proxy-defaults#envoyextensions) configuration entries reference documentation.
|
|
|
|
!> **Warning:** Applying `EnvoyExtensions` to `ProxyDefaults` may produce unintended consequences. We recommend enabling `EnvoyExtensions` with `ServiceDefaults` in most cases.
|
|
|
|
Refer to [Configuration specification](#configuration-specification) section to find a full list of arguments for the Lua Envoy extension.
|
|
|
|
### Apply the configuration entry
|
|
|
|
Apply the `proxy-defaults` or `service-defaults` configuration entry.
|
|
|
|
<Tabs>
|
|
<Tab heading="HCL" group="hcl">
|
|
|
|
```shell-session
|
|
$ consul config write lua-envoy-extension-proxy-defaults.hcl
|
|
```
|
|
|
|
</Tab>
|
|
<Tab heading="JSON" group="json">
|
|
|
|
```shell-session
|
|
$ consul config write lua-envoy-extension-proxy-defaults.json
|
|
|
|
```
|
|
|
|
</Tab>
|
|
<Tab heading="Kubernetes" group="kubernetes">
|
|
|
|
```shell-session
|
|
$ kubectl apply lua-envoy-extension-proxy-defaults.yaml
|
|
```
|
|
|
|
</Tab>
|
|
</Tabs>
|
|
|
|
## Examples
|
|
|
|
In the following example, the `service-defaults` configure the Lua Envoy extension to insert the HTTP Lua filter for service `myservice` and add the Consul service name to the`x-consul-service` header for all inbound requests. The `ListenerType` makes it so that the extension applies only on the inbound listener of the service's connect proxy.
|
|
|
|
<CodeBlockConfig filename="lua-envoy-extension.json">
|
|
|
|
```hcl
|
|
Kind = "service-defaults"
|
|
Name = "myservice"
|
|
EnvoyExtensions = [
|
|
{
|
|
Name = "builtin/lua"
|
|
|
|
Arguments = {
|
|
ProxyType = "connect-proxy"
|
|
Listener = "inbound"
|
|
Script = <<EOF
|
|
function envoy_on_request(request_handle)
|
|
local service = request_handle:streamInfo():dynamicMetadata():get("consul")["service"]
|
|
request_handle:headers():add("x-consul-service", service)
|
|
end
|
|
EOF
|
|
}
|
|
}
|
|
]
|
|
```
|
|
|
|
</CodeBlockConfig>
|
|
|
|
Alternatively, you can apply the same extension configuration to [`proxy-defaults`](/consul/docs/connect/config-entries/proxy-defaults#envoyextensions) configuration entries.
|
|
|
|
You can also specify multiple Lua filters through the Envoy extensions. They will not override each other.
|
|
|
|
<CodeBlockConfig filename="lua-envoy-extension.json">
|
|
|
|
```hcl
|
|
Kind = "service-defaults"
|
|
Name = "myservice"
|
|
EnvoyExtensions = [
|
|
{
|
|
Name = "builtin/lua",
|
|
Arguments = {
|
|
ProxyType = "connect-proxy"
|
|
Listener = "inbound"
|
|
Script = <<-EOF
|
|
function envoy_on_request(request_handle)
|
|
meta = request_handle:streamInfo():dynamicMetadata()
|
|
m = meta:get("consul")
|
|
request_handle:headers():add("x-consul-datacenter", m["datacenter1"])
|
|
end
|
|
EOF
|
|
}
|
|
},
|
|
{
|
|
Name = "builtin/lua",
|
|
Arguments = {
|
|
ProxyType = "connect-proxy"
|
|
Listener = "inbound"
|
|
Script = <<-EOF
|
|
function envoy_on_request(request_handle)
|
|
meta = request_handle:streamInfo():dynamicMetadata()
|
|
m = meta:get("consul")
|
|
request_handle:headers():add("x-consul-datacenter", m["datacenter2"])
|
|
end
|
|
EOF
|
|
}
|
|
}
|
|
]
|
|
```
|
|
|
|
</CodeBlockConfig> |