How to encode caller information to match GCP LogEntrySourceLocation

[capthiron]

Hey there! 🙂

I am trying to encode the caller information (file, line & function) so it matches the requirements for GCP LogEntry's LogEntrySourceLocation field. This is important so the caller information can be automatically extracted by GCP's LogAgent.

A result should look something like the following:

{
  "caller":{
    "file":"get_data.go",
    "line":"142",
    "function":"getData"
  }
}

Setting the callerKey to the value required by LogEntry was not a Problem, neither was gathering the required information (file, line& function). Unfortunately I could not figure out a way to implement a custom CallerEncoder to match the required format with a nested object.

// An excerpt from zapcore/encoder.go:264
// A CallerEncoder serializes an EntryCaller to a primitive type.
type CallerEncoder func(EntryCaller, PrimitiveArrayEncoder)

I am wondering whether it is possible to achieve this with the given PrimitiveArrayEncoder. I saw functions like AppendObject(), but these were only accessible from an ArrayEncoder.
I hope I was able to explain the problem in an understandable way.

Great regards,
Dario