Codable extension for Logger.MetadataValue

[bwdmr]

This Codable extension for Logger.MetadataValue provides encoding and decoding functionality, mapping MetadataValue cases (string, stringConvertible, dictionary, array) into JSON-compatible formats using the associated type and value keys

• Container Encoding:
  • Each case of MetadataValue is encoded with an explicit type (ValueType) and corresponding value.
  • stringConvertible is encoded using .description since we need it in a String format.
• Container Decoding
  • When decoding, ValueType is first extracted to determine the case.
  • For stringConvertible, the String value is decoded and then assigned back to stringConvertible.
  • Dictionary and array cases are decoded as Logger.Metadata and [Logger.MetadataValue] respectively.

[ktoso]

I think that's fine but I'd like to request a test (can pull in foundation and use JSON), so that we check this is covered.

[FranzBusch]

I am not yet convinced this is the right thing to do. Encoding enums is always a bit tricky and results in interesting JSON formats. Not saying we shouldn't do this but I would like to understand the motivation a bit more here.

[bwdmr]

generally meant for metadatavalue to be compatible with codable.
it was meant for cases like string

for enums would imply a codable constraint. enforcing a custom implementation each time one would rely on it.
i dont know how excessive this requirement is.

might be too much to ask. what do you guys think

[FranzBusch]

generally meant for metadatavalue to be compatible with codable. it was meant for cases like string

for enums would imply a codable constraint. enforcing a custom implementation each time one would rely on it. i dont know how excessive this requirement is.

might be too much to ask. what do you guys think

Thanks for explaining your intention. I remain unconvinced that this is the right thing to do. Specifically because the way we encode this is very custom to how the Swift type is structured. I also don't see this as something that is blocking people from writing their own backends that have to emit metadata values as JSON. We have many log handler backends that do this already and they often hand roll the JSON emission for better performance.