ocaml-trace/trace/_doc-dir/CHANGES.md

0.12

• use current_span when entering spans or sending messages
• add Trace.Ambient_span_provider.t concept, to track the current span. It is not part of the collector and is optional.
• add trace.thread-local-storage optional library that implements the Ambient_span_provider.t
• add a runtime events collector, + test, in trace-runtime-events
• add {thread,process}_sort_index extension + TEF support

0.11

• entire rework of the collector, now lighter, and using an open sum type for span. No global state is required anymore.
• add enabled to the collector
• extensible metric; pass level around in collector
• remove unused deps on hmap, thread-local-storage
• add Trace.with_setup_collector
• add trace.debug to find what spans were not closed on exit
• remove dead code and on_tracing_error
• remove subscriber entirely
• core: remove current_span from collector
• update deps to ppxlib=0.37~
• breaking: use poly variants for user_data/span_flavor
• use at_exit in trace_tef and tldrs
• fix fuchsia: bound check

0.10

• breaking: manual spans now take a explicit_span_ctx as parent, that can potentially be transmitted across processes/machines. It also is intended to be more compatible with OTEL.

• breaking trace.subscriber: timestamps are int64ns now, not floats

• breaking trace: pass a string trace_id in manual spans, which helps for backends such as opentelemetry. It's also useful for extensions.

• refactor trace-fuchsia: full revamp of the library, modularized, using subscriber API

• refactor trace-tef: split into exporter,writer,subscriber, using subscriber API

• feat: add trace.event, useful for background threads

• feat trace.subscriber: add Span_tbl, and a depopt on picos_aux

• feat trace.subscriber: tee a whole array at once

• feat tef-tldrs: use EMIT_TEF_AT_EXIT

• feat trace.subscriber: depopt on unix for timestamps

• refactor trace-tef: depopt on unix for TEF timestamps

0.9.1

• fix: upper bound on ppxlib
• feat trace-tef: print names of non-closed spans upon exit
• fix: block signals in background threads

0.9

• add an extensible sum type, so users can implement custom events. For example an OTEL collector can provide custom events to link two spans to one another.

0.8

• add trace.subscriber instead of a separate library

• add trace-tef.tldrs, to trace multiple processes easily (with external rust daemon)

• breaking: trace-tef: use mtime.now, not a counter, for multiproc

• trace-fuchsia: require thread-local-storage 0.2

0.7

• feat: add levels to Trace_core. Levels are similar to logs levels, to help control verbosity.

• add hmap as a depopt (#28)

• fix: truncate large strings in fuchsia

0.6

• add ppx_trace for easier instrumentation.
  • let%trace span = "foo" in … will enter a scope span named "foo"
  • let%trace () = "foo" in … will enter a scope named "foo" with a hidden name
• add trace-fuchsia backend, which produces traces in the binary format of fuchsia. These traces are reasonably efficient to produce (~60ns per span on my machines) and reasonably compact on disk, at least compared to the TEF backend.

0.5

• perf: reduce overhead in trace-tef
• perf: add Mpsc_queue, adapted from picos, to trace-tef

0.4

• add ?data to counter_int and counter_float

• add float to user data

• add add_data_to_current_span and add_data_to_manual_span

• make explicit_span.meta mutable

• trace-tef: write to trace.json if env variable TRACE is either 1 or true

• trace-tef: emit function name, if provided, as a metadata key/value pair

• re-export trace.core in trace

• perf: in trace-tef, use broadcast instead of signal in the job queue

0.3

• add explicit spans, for more precise tracing
• rename repo to ocaml-trace
• trace-tef: add a ticker thread to ensure we flush the file regularly

0.2

• trace-tef: additional argument to with_setup; env for "stdout"/"stderr"
• refactor: avoid conflicting with stdlib Trace module by adding sublibrary trace.core. Programs that use compiler-libs.toplevel should use trace.core directly, because using trace will cause linking errors.
• perf(trace-tef): improve behavior of collector under contention by pulling all events at once in the worker

0.1

initial release