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The problem is that the logging library isn't typed enough: it should require some JSON document object instead of text. If it requires text, it must actually a

The problem is that the logging library isn't typed enough: it should require some JSON document object instead of text. If it requires text, it must actually accept text. Silently dropping log messages, without even logging that logging is failing, is an even worse defect since it is also terrible without typing errors, e.g. in the case of clients earnestly trying to pass JSON as text but making some mistake with quotation, escaping, commas etc because it is text. So the logging library is inadequately designed and not "semi-sensible" at all.

ezrast 4y ago
While serde is the de facto standard for JSON in Rust, it's not actually in the standard library, so there's no one true "JSON document" type for the logger to accept. Anyway, the point of the JSON serializer taking a writer is so that it can push tokens straight to an IO device (the network, in this case), one by one, without having to hold the entire abstract structure in memory. And even if you had a dedicated "JsonWriter" interface for streaming that validates on the way out, you'd have cases where a string is already known to be valid JSON but to send it you have to pay the cost of an extra validation for no good reason. I love me some strong, static types, but sometimes you gotta let bytes be bytes. The silently dropping bad input, yeah, that part was just bad developer experience on the vendor's part.
- tialaramex 4y ago
  If they want a whole JSON Document here - which apparently they do - but they don't want to just admit that everybody uses serde, they can provide a Trait like OurJSONLogRecord and then provide the implementation for OurJSONLogRecord on the serde type. You can implement it on whatever internal JSON documents are ready to be logged. This OurJSONLogRecord still surfaces the undocumented assumption, "Oh, we need the entire JSON document, we didn't realise anybody would want to stream data" whereas the Write trait does not.

ezrast 4y ago

While serde is the de facto standard for JSON in Rust, it's not actually in the standard library, so there's no one true "JSON document" type for the logger to accept. Anyway, the point of the JSON serializer taking a writer is so that it can push tokens straight to an IO device (the network, in this case), one by one, without having to hold the entire abstract structure in memory. And even if you had a dedicated "JsonWriter" interface for streaming that validates on the way out, you'd have cases where a string is already known to be valid JSON but to send it you have to pay the cost of an extra validation for no good reason. I love me some strong, static types, but sometimes you gotta let bytes be bytes. The silently dropping bad input, yeah, that part was just bad developer experience on the vendor's part.

tialaramex 4y ago
If they want a whole JSON Document here - which apparently they do - but they don't want to just admit that everybody uses serde, they can provide a Trait like OurJSONLogRecord and then provide the implementation for OurJSONLogRecord on the serde type. You can implement it on whatever internal JSON documents are ready to be logged. This OurJSONLogRecord still surfaces the undocumented assumption, "Oh, we need the entire JSON document, we didn't realise anybody would want to stream data" whereas the Write trait does not.