Access application version in components

[james-bebbington]

Is your feature request related to a problem? Please describe.
I would like to include the application version in metadata on requests sent by an exporter.

Describe the solution you'd like
Add the version string to the parameters passed to components on initialization, i.e. update https://github.com/open-telemetry/opentelemetry-collector/blob/v0.8.0/component/exporter.go#L97 (similar for other components)

When building the pipelines, set this value based on the value provided in https://github.com/open-telemetry/opentelemetry-collector/blob/v0.8.0/service/service.go#L109

[nilebox]

While version is the immediate use case that needs this feature, it may make more sense to support a generic way of passing the pipeline-level metadata.

e.g. if in the exporter we want to distinguish the "distro" it's being used in (opentelemetry-collector, opentelemetry-collector-contrib, or some vendor-specific binary like GoogleCloudPlatform/opentelemetry-operations-collector), we may declare a struct like

type ApplicationInfo interface {
  Name() string    // e.g. "opentelemetry-collector"
  Version() string // e.g. "v0.10.0"
}

and pass it to all component constructors.

[james-bebbington]

we may declare a struct ... and pass it to all component constructors.

Good point - maybe we could just pass in the ApplicationStartInfo struct directly: https://github.com/open-telemetry/opentelemetry-collector/blob/v0.8.0/service/service.go#L101

[andrewhsu]

Closing this as done because PR #1582 was merged