examples/properties run failed

[codefinger23]

RT

root cause is propertyPath need change from

var propertyPrefix = []string{
	"route_metadata",
	"filter_metadata",
	"envoy.filters.http.wasm",
}

to

var propertyPrefix = []string{
	"xds",
	"route_metadata",
	"filter_metadata",
	"envoy.filters.http.wasm",
}

[leonm1]

Thank you for filing an issue! The associated test doesn't look like it is failing in CI, can you share more details about the test environment? Did you compile the plugin and use with an Envoy WasmFilter? Which version of Envoy?

[feliperfmarques]

Hi @codefinger23 @leonm1,

I also ran into the same issue and spent quite some time figuring it out, since most of the examples out there are outdated or incorrect. According to the Envoy documentation, to access configuration attributes you need to start the path with xds (https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/advanced/attributes#configuration-attributes).

For example, to access a specific label of a pod with the Istio sidecar injected, Istio injects the label at the path node.metadata.LABELS."<mylabel>". Confirming via istioctl gives:

$ istioctl proxy-config bootstrap <my-pod>.<my-namespace> -o json | jq .bootstrap.node.metadata.LABELS."<mylabel>"

<my-label-value>

The same Istio scenario can be simulated locally with func-e using the following node configuration:

...

node:
  id: test-node
  cluster: test-cluster
  metadata:
    NAMESPACE: "test-namespace"
    WORKLOAD_NAME: "test-workload"
    LABELS:
      <my-label>: "<my-value>"

...

However, when trying to access the label via GetProperty using the path node.metadata.LABELS, I received the error: returned by host: not found:

_labelValue, err := proxywasm.GetProperty([]string{
    "node", "metadata", "LABELS", "<my-label>",
})
if err != nil {
    proxywasm.LogWarn("Failed to get node.metadata.labels property")
} else {
    proxywasm.LogInfof("Success: %v", _labelValue)
}

After a lot of searching, I realized from the documentation that the error was due to missing the xds prefix. The correct way is:

_labelValue, err := proxywasm.GetProperty([]string{
    "xds", "node", "metadata", "LABELS", "<my-label>",
})
if err != nil {
    proxywasm.LogWarn("Failed to get node.metadata.labels property")
} else {
    proxywasm.LogInfof("Success: %v", _labelValue)
}

For context, I was testing locally with func-e (envoy 1.34.0) against a remote environment running Istio 1.27.0 (envoy 1.35.0).

[codefinger23]

I was testing with envoy 1.34.0 too ;
@leonm1 @feliperfmarques
I found the behavior change from commit
envoyproxy/envoy@ff991f3

Is anyone interested in fixing the issue in the Example section? If not, I'm happy to submit a PR to fix it.