Move tracing to pkg/tracing

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/tracing/tracing.go

@@ -0,0 +1,116 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package tracing
+
+import (
+	"context"
+	"net/http"
+
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// StartConfig defines configuration for a new span object.
+type StartConfig struct {
+	spanOpts []trace.SpanStartOption
+}
+
+type SpanOpt func(config *StartConfig)
+
+// UpdateHTTPClient updates the http client with the necessary otel transport
+func UpdateHTTPClient(client *http.Client, name string) {
+	client.Transport = otelhttp.NewTransport(
+		client.Transport,
+		otelhttp.WithSpanNameFormatter(func(operation string, r *http.Request) string {
+			return name
+		}),
+	)
+}
+
+// StartSpan starts child span in a context.
+func StartSpan(ctx context.Context, opName string, opts ...SpanOpt) (context.Context, *Span) {
+	config := StartConfig{}
+	for _, fn := range opts {
+		fn(&config)
+	}
+	tracer := otel.Tracer("")
+	if parent := trace.SpanFromContext(ctx); parent != nil && parent.SpanContext().IsValid() {
+		tracer = parent.TracerProvider().Tracer("")
+	}
+	ctx, span := tracer.Start(ctx, opName, config.spanOpts...)
+	return ctx, &Span{otelSpan: span}
+}
+
+// SpanFromContext returns the current Span from the context.
+func SpanFromContext(ctx context.Context) *Span {
+	return &Span{
+		otelSpan: trace.SpanFromContext(ctx),
+	}
+}
+
+// Span is wrapper around otel trace.Span.
+// Span is the individual component of a trace. It represents a
+// single named and timed operation of a workflow that is traced.
+type Span struct {
+	otelSpan trace.Span
+}
+
+// End completes the span.
+func (s *Span) End() {
+	s.otelSpan.End()
+}
+
+// AddEvent adds an event with provided name and options.
+func (s *Span) AddEvent(name string, options ...trace.EventOption) {
+	s.otelSpan.AddEvent(name, options...)
+}
+
+// SetStatus sets the status of the current span.
+// If an error is encountered, it records the error and sets span status to Error.
+func (s *Span) SetStatus(err error) {
+	if err != nil {
+		s.otelSpan.RecordError(err)
+		s.otelSpan.SetStatus(codes.Error, err.Error())
+	} else {
+		s.otelSpan.SetStatus(codes.Ok, "")
+	}
+}
+
+// SetAttributes sets kv as attributes of the span.
+func (s *Span) SetAttributes(kv ...attribute.KeyValue) {
+	s.otelSpan.SetAttributes(kv...)
+}
+
+// Name sets the span name by joining a list of strings in dot separated format.
+func Name(names ...string) string {
+	return makeSpanName(names...)
+}
+
+// Attribute takes a key value pair and returns attribute.KeyValue type.
+func Attribute(k string, v interface{}) attribute.KeyValue {
+	return any(k, v)
+}
+
+// HTTPStatusCodeAttributes generates attributes of the HTTP namespace as specified by the OpenTelemetry
+// specification for a span.
+func HTTPStatusCodeAttributes(code int) []attribute.KeyValue {
+	return []attribute.KeyValue{semconv.HTTPStatusCodeKey.Int(code)}
+}