89 lines
3.8 KiB
Go
89 lines
3.8 KiB
Go
// Copyright 2019 OpenTelemetry Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package component
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import (
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"context"
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"go.opentelemetry.io/collector/config/configmodels"
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)
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// Component is either a receiver, exporter, processor or extension.
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type Component interface {
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// Start tells the component to start. Host parameter can be used for communicating
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// with the host after Start() has already returned. If error is returned by
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// Start() then the collector startup will be aborted.
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// If this is an exporter component it may prepare for exporting
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// by connecting to the endpoint.
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Start(ctx context.Context, host Host) error
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// Shutdown is invoked during service shutdown.
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Shutdown(ctx context.Context) error
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}
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// Kind specified one of the 4 components kinds, see consts below.
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type Kind int
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const (
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_ Kind = iota // skip 0, start types from 1.
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KindReceiver
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KindProcessor
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KindExporter
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KindExtension
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)
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// Host represents the entity that is hosting a Component. It is used to allow communication
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// between the Component and its host (normally the service.Application is the host).
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type Host interface {
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// ReportFatalError is used to report to the host that the extension
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// encountered a fatal error (i.e.: an error that the instance can't recover
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// from) after its start function had already returned.
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ReportFatalError(err error)
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// GetFactory of the specified kind. Returns the factory for a component type.
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// This allows components to create other components. For example:
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// func (r MyReceiver) Start(host component.Host) error {
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// apacheFactory := host.GetFactory(KindReceiver,"apache").(component.ReceiverFactory)
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// receiver, err := apacheFactory.CreateMetricsReceiver(...)
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// ...
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// }
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// GetFactory can be called by the component anytime after Start() begins and
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// until Shutdown() is called. Note that the component is responsible for destroying
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// other components that it creates.
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GetFactory(kind Kind, componentType configmodels.Type) Factory
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// Return map of extensions. Only enabled and created extensions will be returned.
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// Typically is used to find an extension by type or by full config name. Both cases
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// can be done by iterating the returned map. There are typically very few extensions
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// so there there is no performance implications due to iteration.
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GetExtensions() map[configmodels.Extension]ServiceExtension
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// Return map of exporters. Only enabled and created exporters will be returned.
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// Typically is used to find exporters by type or by full config name. Both cases
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// can be done by iterating the returned map. There are typically very few exporters
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// so there there is no performance implications due to iteration.
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// This returns a map by DataType of maps by exporter configs to the exporter instance.
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// Note that an exporter with the same name may be attached to multiple pipelines and
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// thus we may have an instance of the exporter for multiple data types.
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// This is an experimental function that may change or even be removed completely.
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GetExporters() map[configmodels.DataType]map[configmodels.Exporter]Exporter
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}
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// Factory interface must be implemented by all component factories.
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type Factory interface {
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// Type gets the type of the component created by this factory.
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Type() configmodels.Type
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}
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