tracer

type DelegatingCarrier interface {
	SetState(traceID uuid.UUID, spanID uint64, sampled bool)
	State() (traceID uuid.UUID, spanID uint64, sampled bool)
	SetBaggageItem(key, value string)
	GetBaggage(func(key, value string))
}

type EventBaggage struct {
	Key, Value string
}

type EventCreate struct{ OperationName string }

type EventFinish RawSpan

type EventLog opentracing.LogData

type EventLogFields opentracing.LogRecord

type EventTag struct {
	Key   string
	Value interface{}
}

type InMemorySpanRecorder struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

type Options struct {
	// ShouldSample is a function which is called when creating a new Span and
	// determines whether that Span is sampled. The randomized TraceID is supplied
	// to allow deterministic sampling decisions to be made across different nodes.
	// For example,
	//
	//   func(traceID uuid.UUID) { return true }
	//
	ShouldSample func(traceID uuid.UUID) bool
	// TrimUnsampledSpans turns potentially expensive operations on unsampled
	// Spans into no-ops. More precisely, tags and log events are silently
	// discarded. If NewSpanEventListener is set, the callbacks will still fire.
	TrimUnsampledSpans bool
	// Recorder receives Spans which have been finished.
	Recorder SpanRecorder
	// NewSpanEventListener can be used to enhance the tracer by effectively
	// attaching external code to trace events. See NetTraceIntegrator for a
	// practical example, and event.go for the list of possible events.
	NewSpanEventListener func() func(SpanEvent)
	// DropAllLogs turns log events on all Spans into no-ops.
	// If NewSpanEventListener is set, the callbacks will still fire.
	DropAllLogs bool
	// MaxLogsPerSpan limits the number of Logs in a span (if set to a nonzero
	// value). If a span has more logs than this value, logs are dropped as
	// necessary (and replaced with a log describing how many were dropped).
	//
	// About half of the MaxLogPerSpan logs kept are the oldest logs, and about
	// half are the newest logs.
	//
	// If NewSpanEventListener is set, the callbacks will still fire for all log
	// events. This value is ignored if DropAllLogs is true.
	MaxLogsPerSpan int
	// DebugAssertSingleGoroutine internally records the ID of the goroutine
	// creating each Span and verifies that no operation is carried out on
	// it on a different goroutine.
	// Provided strictly for development purposes.
	// Passing Spans between goroutine without proper synchronization often
	// results in use-after-Finish() errors. For a simple example, consider the
	// following pseudocode:
	//
	//  func (s *Server) Handle(req nethttp.Request) error {
	//    sp := s.StartSpan("server")
	//    defer sp.Finish()
	//    wait := s.queueProcessing(opentracing.ContextWithSpan(context.Background(), sp), req)
	//    select {
	//    case resp := <-wait:
	//      return resp.Error
	//    case <-time.After(10*time.Second):
	//      sp.LogEvent("timed out waiting for processing")
	//      return ErrTimedOut
	//    }
	//  }
	//
	// This looks reasonable at first, but a request which spends more than ten
	// seconds in the queue is abandoned by the main goroutine and its trace
	// finished, leading to use-after-finish when the request is finally
	// processed. Note also that even joining on to a finished Span via
	// StartSpanWithOptions constitutes an illegal operation.
	//
	// Code bases which do not require (or decide they do not want) Spans to
	// be passed across goroutine boundaries can run with this flag enabled in
	// tests to increase their chances of spotting wrong-doers.
	DebugAssertSingleGoroutine bool
	// DebugAssertUseAfterFinish is provided strictly for development purposes.
	// When set, it attempts to exacerbate issues emanating from use of Spans
	// after calling Finish by running additional assertions.
	DebugAssertUseAfterFinish bool
	// EnableSpanPool enables the use of a pool, so that the tracer reuses spans
	// after Finish has been called on it. Adds a slight performance gain as it
	// reduces allocations. However, if you have any use-after-finish race
	// conditions the code may panic.
	EnableSpanPool bool
	// Func to call when a panic has been detected when a span is finalizing
	OnSpanFinishPanic func(rSpan *RawSpan, err **errors.Error)
}

type RawSpan struct {
	// Those recording the RawSpan should also record the contents of its
	// SpanContext.
	Context SpanContext

	// The SpanID of this SpanContext's first intra-trace reference (i.e.,
	// "parent"), or 0 if there is no parent.
	ParentSpanID uint64

	// The name of the "operation" this span is an instance of. (Called a "span
	// name" in some implementations)
	Operation string

	// We store <start, duration> rather than <start, end> so that only
	// one of the timestamps has global clock uncertainty issues.
	Start    time.Time
	Duration time.Duration

	// Essentially an extension mechanism. Can be used for many purposes,
	// not to be enumerated here.
	Tags opentracing.Tags

	// The span's "microlog".
	Logs []opentracing.LogRecord
}

type Span interface {
	opentracing.Span

	// Operation names the work done by this span instance
	Operation() string

	// Start indicates when the span began
	Start() time.Time

	// Sets the start time
	SetStart(start time.Time) opentracing.Span

	// Log fields with timestamp
	LogFieldsWithTimestamp(t time.Time, fields ...log.Field)

	// Set tag without validation
	UnsafeSetTag(key string, value interface{}) opentracing.Span
}

type SpanContext struct {
	// A probabilistically unique identifier for a [multi-span] trace.
	TraceID uuid.UUID

	// A probabilistically unique identifier for a span.
	SpanID uint64

	// Whether the trace is sampled.
	Sampled bool

	// The span's associated baggage.
	Baggage map[string]string // initialized on first use
}

type SpanEvent interface{}

type SpanRecorder interface {
	// Implementations must determine whether and where to store `span`.
	RecordSpan(span RawSpan)
}

type Tracer interface {
	opentracing.Tracer

	// Options gets the Options used in New() or NewWithOptions().
	Options() Options
}