tracing_register.go

// Copyright © 2017 The virtual-kubelet 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 root

import (
	"github.com/virtual-kubelet/virtual-kubelet/errdefs"
	"go.opencensus.io/trace"
)

// TracingExporterOptions is the options passed to the tracing exporter init function.
type TracingExporterOptions struct { //nolint: golint
	Tags        map[string]string
	ServiceName string
}

var (
	tracingExporters = make(map[string]TracingExporterInitFunc)
)

// TracingExporterInitFunc is the function that is called to initialize an exporter.
// This is used when registering an exporter and called when a user specified they want to use the exporter.
type TracingExporterInitFunc func(TracingExporterOptions) (trace.Exporter, error)

// RegisterTracingExporter registers a tracing exporter.
// For a user to select an exporter, it must be registered here.
func RegisterTracingExporter(name string, f TracingExporterInitFunc) {
	tracingExporters[name] = f
}

// GetTracingExporter gets the specified tracing exporter passing in the options to the exporter init function.
// For an exporter to be available here it must be registered with `RegisterTracingExporter`.
func GetTracingExporter(name string, opts TracingExporterOptions) (trace.Exporter, error) {
	f, ok := tracingExporters[name]
	if !ok {
		return nil, errdefs.NotFoundf("tracing exporter %q not found", name)
	}
	return f(opts)
}

// AvailableTraceExporters gets the list of registered exporters
func AvailableTraceExporters() []string {
	out := make([]string, 0, len(tracingExporters))
	for k := range tracingExporters {
		out = append(out, k)
	}
	return out
}