Drop Jackson support on the Exporters

[brunobat]

Initially we thought on providing support for Jackson 3: https://github.com/FasterXML/jackson/wiki/Jackson-Release-3.0
The OpenTelemetry exporter depends on Jackson 2 and we should provide an alternative for future applications requiring Jackson 3.

This affects:

• Exporters. See: io.opentelemetry.exporter.internal.marshal.JsonSerializer
• Declarative config.

In the end, we think dropping Jackson usage will cause less problems and be less complex for the codebase.

[jack-berg]

For declarative config is affected. I think a good way to do this is to make the task of taking parsing YAML and/or converting to pojo pluggable via SPI.

Roughly, the process looks like:

Object parsedYaml = org.snakeyaml.engine.v2.api.Load.loadFromInputStream(InputStream);
OpenTelemetryConfigurationModel model = com.fasterxml.jackson.databind.ObjectMapper.convertValue(parsedYaml, OpenTelemetryConfigurationModel.class);
OpenTelemetrySdk openTelemetrySdk = create(model);

So things we need to be pluggable:

• Parsing YAML InputStream to Object
• Converting Object to POJO

The serialization stuff in the unsupported OTLP json path adds more complexity since the API surface area of JsonSerializer is large.

[jack-berg]

Maybe we should rip out jackson from the serialization path. We already do JSON serialization for Value here: https://github.com/open-telemetry/opentelemetry-java/blob/main/api/all/src/main/java/io/opentelemetry/api/common/JsonEncoding.java

Doesn't seem that hard.

[brunobat]

Maybe we should rip out jackson from the serialization path. We already do JSON serialization for Value here: https://github.com/open-telemetry/opentelemetry-java/blob/main/api/all/src/main/java/io/opentelemetry/api/common/JsonEncoding.java

Doesn't seem that hard.

This would be preferable. I've been working on a PoC, just for the Exporter and the added complexity seems too much.

If we want to do the JSon serialization ourselves and need more features, We have this implementation as reference: https://github.com/quarkusio/quarkus/blob/ac7402d11a61dc757bf3c3e89175220523edce2b/core/builder/src/main/java/io/quarkus/builder/Json.java#L27

The PoC, just for the exporters is here: #8544

... Also, Jackson 3 requires Java 17.

[brunobat]

The current approach is to drop the Jackson dependency altogether.
@jack-berg, renamed the issue.