chore: vendor

vendor/go.opentelemetry.io/otel/trace/doc.go

@@ -0,0 +1,119 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+/*
+Package trace provides an implementation of the tracing part of the
+OpenTelemetry API.
+
+To participate in distributed traces a Span needs to be created for the
+operation being performed as part of a traced workflow. In its simplest form:
+
+	var tracer trace.Tracer
+
+	func init() {
+		tracer = otel.Tracer("instrumentation/package/name")
+	}
+
+	func operation(ctx context.Context) {
+		var span trace.Span
+		ctx, span = tracer.Start(ctx, "operation")
+		defer span.End()
+		// ...
+	}
+
+A Tracer is unique to the instrumentation and is used to create Spans.
+Instrumentation should be designed to accept a TracerProvider from which it
+can create its own unique Tracer. Alternatively, the registered global
+TracerProvider from the go.opentelemetry.io/otel package can be used as
+a default.
+
+	const (
+		name    = "instrumentation/package/name"
+		version = "0.1.0"
+	)
+
+	type Instrumentation struct {
+		tracer trace.Tracer
+	}
+
+	func NewInstrumentation(tp trace.TracerProvider) *Instrumentation {
+		if tp == nil {
+			tp = otel.TracerProvider()
+		}
+		return &Instrumentation{
+			tracer: tp.Tracer(name, trace.WithInstrumentationVersion(version)),
+		}
+	}
+
+	func operation(ctx context.Context, inst *Instrumentation) {
+		var span trace.Span
+		ctx, span = inst.tracer.Start(ctx, "operation")
+		defer span.End()
+		// ...
+	}
+
+# API Implementations
+
+This package does not conform to the standard Go versioning policy; all of its
+interfaces may have methods added to them without a package major version bump.
+This non-standard API evolution could surprise an uninformed implementation
+author. They could unknowingly build their implementation in a way that would
+result in a runtime panic for their users that update to the new API.
+
+The API is designed to help inform an instrumentation author about this
+non-standard API evolution. It requires them to choose a default behavior for
+unimplemented interface methods. There are three behavior choices they can
+make:
+
+  - Compilation failure
+  - Panic
+  - Default to another implementation
+
+All interfaces in this API embed a corresponding interface from
+[go.opentelemetry.io/otel/trace/embedded]. If an author wants the default
+behavior of their implementations to be a compilation failure, signaling to
+their users they need to update to the latest version of that implementation,
+they need to embed the corresponding interface from
+[go.opentelemetry.io/otel/trace/embedded] in their implementation. For
+example,
+
+	import "go.opentelemetry.io/otel/trace/embedded"
+
+	type TracerProvider struct {
+		embedded.TracerProvider
+		// ...
+	}
+
+If an author wants the default behavior of their implementations to panic, they
+can embed the API interface directly.
+
+	import "go.opentelemetry.io/otel/trace"
+
+	type TracerProvider struct {
+		trace.TracerProvider
+		// ...
+	}
+
+This option is not recommended. It will lead to publishing packages that
+contain runtime panics when users update to newer versions of
+[go.opentelemetry.io/otel/trace], which may be done with a trasitive
+dependency.
+
+Finally, an author can embed another implementation in theirs. The embedded
+implementation will be used for methods not defined by the author. For example,
+an author who wants to default to silently dropping the call can use
+[go.opentelemetry.io/otel/trace/noop]:
+
+	import "go.opentelemetry.io/otel/trace/noop"
+
+	type TracerProvider struct {
+		noop.TracerProvider
+		// ...
+	}
+
+It is strongly recommended that authors only embed
+[go.opentelemetry.io/otel/trace/noop] if they choose this default behavior.
+That implementation is the only one OpenTelemetry authors can guarantee will
+fully implement all the API interfaces when a user updates their API.
+*/
+package trace // import "go.opentelemetry.io/otel/trace"