GCloud Logging Write - Json as String inside a Structured Logs JsonPayload.message Field

Question

I am currently working with gcloud monitoring. I searched for a way to write log messages similar to already incoming logs. To mimic the real log entry, I am writing a log from a pod via "echo".

My goal is to write a log entry with the following structure:

{
  ....
  "key1":"value1",
  jsonPayload: {
      message: "demo_message {"key1":"value1", "message":"demo entry {"key":"value"}", "key2":"value"}" 
  },
  "key2":"value2",
  ...
}

The main problem occures when using my structured log (gcp structured logging), that contains a "message" key with a string value field. The value field itself contains json-code. The structure is the following:

{ \"key1\":\"value1\", \"message\": \"demo_message {"key":"value"}\", \"key2\":\"abc\"}

The executed code (namespace and podname are substitutes):

kubectl exec -it -n namespacename podname -- bash -c "echo '{ \"key1\":\"value1\", \"message\": \"demo entry {"key":"value"}\", \"key2\":\"abc\"}' >/proc/1/fd/1 "

The execution results in a log entry that doesn't write the quotes around the key-value pair inside the message string, which results in the following output:

{
  ....
  jsonPayload: {
      message: "demo_message {"key1":"value1", "message":"demo entry {key:value}" "key2":"value"}" 
  }
  ...
}

When escaping the quotes around the key-value pair in the execution, the entire entry becomes a textPayload value, which is not a desired output:

{
  ....
  textPayload:"demo_message {"key1":"value1", "message":"demo entry {"key":"value"}" "key2":"value"}",
  ...
}

Is there a simple solution to specify for the logging agend that the entire message value is a string?