[VOL-3187]Pass Context down the execution call hierarchy across ofagent codebase
Change-Id: Ia5f2fa1509beefe0ddc427b83e39d2702782db8f
diff --git a/vendor/github.com/opentracing/opentracing-go/gocontext.go b/vendor/github.com/opentracing/opentracing-go/gocontext.go
new file mode 100644
index 0000000..08c00c0
--- /dev/null
+++ b/vendor/github.com/opentracing/opentracing-go/gocontext.go
@@ -0,0 +1,60 @@
+package opentracing
+
+import "context"
+
+type contextKey struct{}
+
+var activeSpanKey = contextKey{}
+
+// ContextWithSpan returns a new `context.Context` that holds a reference to
+// `span`'s SpanContext.
+func ContextWithSpan(ctx context.Context, span Span) context.Context {
+ return context.WithValue(ctx, activeSpanKey, span)
+}
+
+// SpanFromContext returns the `Span` previously associated with `ctx`, or
+// `nil` if no such `Span` could be found.
+//
+// NOTE: context.Context != SpanContext: the former is Go's intra-process
+// context propagation mechanism, and the latter houses OpenTracing's per-Span
+// identity and baggage information.
+func SpanFromContext(ctx context.Context) Span {
+ val := ctx.Value(activeSpanKey)
+ if sp, ok := val.(Span); ok {
+ return sp
+ }
+ return nil
+}
+
+// StartSpanFromContext starts and returns a Span with `operationName`, using
+// any Span found within `ctx` as a ChildOfRef. If no such parent could be
+// found, StartSpanFromContext creates a root (parentless) Span.
+//
+// The second return value is a context.Context object built around the
+// returned Span.
+//
+// Example usage:
+//
+// SomeFunction(ctx context.Context, ...) {
+// sp, ctx := opentracing.StartSpanFromContext(ctx, "SomeFunction")
+// defer sp.Finish()
+// ...
+// }
+func StartSpanFromContext(ctx context.Context, operationName string, opts ...StartSpanOption) (Span, context.Context) {
+ return StartSpanFromContextWithTracer(ctx, GlobalTracer(), operationName, opts...)
+}
+
+// StartSpanFromContextWithTracer starts and returns a span with `operationName`
+// using a span found within the context as a ChildOfRef. If that doesn't exist
+// it creates a root span. It also returns a context.Context object built
+// around the returned span.
+//
+// It's behavior is identical to StartSpanFromContext except that it takes an explicit
+// tracer as opposed to using the global tracer.
+func StartSpanFromContextWithTracer(ctx context.Context, tracer Tracer, operationName string, opts ...StartSpanOption) (Span, context.Context) {
+ if parentSpan := SpanFromContext(ctx); parentSpan != nil {
+ opts = append(opts, ChildOf(parentSpan.Context()))
+ }
+ span := tracer.StartSpan(operationName, opts...)
+ return span, ContextWithSpan(ctx, span)
+}