[componentstatus] Add Reporter interface

.chloggen/componentstatus-add-reporter-interface.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: componentstatus
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add new Reporter interface to define how to report a status via a `component.Host` implementation
+
+# One or more tracking issues or pull requests related to the change
+issues: [10852]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

component/componentstatus/status.go

@@ -11,8 +11,20 @@ package componentstatus // import "go.opentelemetry.io/collector/component/compo
 
 import (
 	"time"
+
+	"go.opentelemetry.io/collector/component"
 )
 
+// Reporter is an extra interface for `component.Host` implementations.
+// A Reporter defines how to report a `componentstatus.Event`.
+type Reporter interface {
+	// Report allows a component to report runtime changes in status. The service
+	// will automatically report status for a component during startup and shutdown. Components can
+	// use this method to report status after start and before shutdown. For more details about
+	// component status reporting see: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-status.md
+	Report(*Event)
+}
+
 // Watcher is an extra interface for Extension hosted by the OpenTelemetry
 // Collector that is to be implemented by extensions interested in changes to component
 // status.
@@ -137,3 +149,12 @@ func StatusIsError(status Status) bool {
 		status == StatusPermanentError ||
 		status == StatusFatalError
 }
+
+// ReportStatus is a helper function that handles checking if the component.Host has implemented Reporter.
+// If it has, the Event is reported. Otherwise, nothing happens.
+func ReportStatus(host component.Host, e *Event) {
+	statusReporter, ok := host.(Reporter)
+	if ok {
+		statusReporter.Report(e)
+	}
+}

component/componentstatus/status_test.go

@@ -8,6 +8,8 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"go.opentelemetry.io/collector/component"
 )
 
 func TestNewStatusEvent(t *testing.T) {
@@ -88,3 +90,42 @@ func TestStatusIsError(t *testing.T) {
 		})
 	}
 }
+
+func Test_ReportStatus(t *testing.T) {
+	t.Run("Reporter implemented", func(t *testing.T) {
+		r := &reporter{}
+		ReportStatus(r, NewEvent(StatusOK))
+		require.True(t, r.reportStatusCalled)
+	})
+
+	t.Run("Reporter not implemented", func(t *testing.T) {
+		h := &host{}
+		ReportStatus(h, NewEvent(StatusOK))
+		require.False(t, h.reportStatusCalled)
+	})
+}
+
+var _ = (component.Host)(nil)
+var _ = (Reporter)(nil)
+
+type reporter struct {
+	reportStatusCalled bool
+}
+
+func (r *reporter) GetExtensions() map[component.ID]component.Component {
+	return nil
+}
+
+func (r *reporter) Report(_ *Event) {
+	r.reportStatusCalled = true
+}
+
+var _ = (component.Host)(nil)
+
+type host struct {
+	reportStatusCalled bool
+}
+
+func (h *host) GetExtensions() map[component.ID]component.Component {
+	return nil
+}