How to write a custom trace exporter
Kong bundled OpenTelemetry plugin in core with a implementation of OTLP/HTTP, but you can still write your own exporter at scale.
Gathering the spans
The spans are stored in the tracer’s buffer.
The buffer is a queue of spans that are awaiting to be sent to the backend.
You can access the buffer and process the span using the
-- Use the global tracer
local tracer = kong.tracing
-- Process the span
local span_processor = function(span)
-- clone the span so it can be processed after the original one is cleared
local span_dup = table.clone(span)
-- you can transform the span, add tags, etc. to other specific data structures
span_processor function should be called in the
log phase of the plugin.
Refer to Github to see the example of a custom trace exporter.