Module passage_span

Description
Data Types
Function Index
Function Details

Span.

Description

Span.

Traces in OpenTracing are defined implicitly by their Spans. In particular, a Trace can be thought of as a directed acyclic graph (DAG) of Spans, where the edges between Spans are called References.
Each Span encapsulates the following state:

An operation name

A start timestamp

A finish timestamp

A set of zero or more key:value Span Tags. The keys must be strings. The values may be strings, bools, or numeric types.

A set of zero or more Span Logs, each of which is itself a key:value map paired with a timestamp. The keys must be strings, though the values may be of any type. Not all OpenTracing implementations must support every value type.

A SpanContext

References to zero or more causally-related Spans (via the SpanContext of those related Spans)

The OpenTracing Data Model

Examples

  %% Registers a tracer
  Context = passage_span_context_null,
  Sampler = passage_sampler_all:new(),
  Reporter = passage_reporter_null:new(),
  ok = passage_tracer_registry:register(tracer, Context, Sampler, Reporter),
 
  %% Starts a span
  MaybeSpan = passage:start_span(example, [{tracer, tracer}]),
  case MaybeSpan of
      undefined -> ok;
      Span      -> example = passage_span:get_operation_name(Span)
  end,
 
  %% Finishes a span
  passage:finish_span(MaybeSpan).

Data Types

log()

log() = {passage:log_fields(), erlang:timestamp()}

Timestamped span log fields.

span()

abstract datatype: span()

Span.

Function Index

get_context/1	Returns the context of `Span`.
get_finish_time/1	Returns the finish time of `Span`.
get_logs/1	Returns the logs of `Span`.
get_operation_name/1	Returns the operation name of `Span`.
get_refs/1	Returns the references of `Span`.
get_start_time/1	Returns the start time of `Span`.
get_tags/1	Returns the tags of `Span`.