go - Get execution ID for Google Cloud Functions triggered from PubSub event

Question

For Google Cloud Functions triggered from HTTP, it is possible to retrieve the execution id by inspecting the headers of the HTTP request ("Function-Execution-Id") :

package p

import (
    "fmt"
    "net/http"
)

func F(w http.ResponseWriter, r *http.Request) {
    executionID := r.Header.Get("Function-Execution-Id")
    fmt.Println(executionID)
}

However, for GCF triggered by PubSub events, I can't find how to retrieve this execution ID :

package p

import (
    "context"
)

type PubSubMessage struct {
    Data []byte `json:"data"`
}

func F(ctx context.Context, m PubSubMessage) error {
    executionID := "" // ???
    fmt.Println(executionID)
    return nil
}

I have looked into the PubSubMessage (https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage), but it only contains data + an empty attributes map.

I have also checked if execution ID is in the metadata handled by the context. However, from my tests, and the docs (https://godoc.org/cloud.google.com/go/functions/metadata#FromContext), only EventID, Timestamp, EventType and Resource are present.

How can I retrieve the execution id of a GCF function triggered by a PubSub event?

Answer 1

Waitting for answers