[component] Move component status reporting public API to new compone…

…ntstatus module (open-telemetry#10730)

#### Description

Duplicates component status reporting features from `component` into a
separate module, `componentstatus`. In a future PR, when
`component.TelemetrySettings.ReportStatus` is removed, I'll update Core
to depend on `componentstatus`.

This work isolates component status public API from `component` and
`extensions`, which will allow us to move forward with their 1.0 work
while component status reporting matures.

<!-- Issue number if applicable -->
#### Link to tracking issue
Related to
open-telemetry#10725

---------

Co-authored-by: Matthew Wear <[email protected]>

.chloggen/componentstatus-new-module.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: new_component
+
+# 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: Adds new componentstatus module that will soon replace status content in component.
+
+# One or more tracking issues or pull requests related to the change
+issues: [10730]
+
+# (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: [api]

Makefile

@@ -259,6 +259,7 @@ check-contrib:
 		-replace go.opentelemetry.io/collector=$(CURDIR) \
 		-replace go.opentelemetry.io/collector/client=$(CURDIR)/client \
 		-replace go.opentelemetry.io/collector/component=$(CURDIR)/component  \
+		-replace go.opentelemetry.io/collector/component/componentstatus=$(CURDIR)/component/componentstatus  \
 		-replace go.opentelemetry.io/collector/config/configauth=$(CURDIR)/config/configauth  \
 		-replace go.opentelemetry.io/collector/config/configcompression=$(CURDIR)/config/configcompression  \
 		-replace go.opentelemetry.io/collector/config/configgrpc=$(CURDIR)/config/configgrpc  \
@@ -321,6 +322,7 @@ restore-contrib:
 		-dropreplace go.opentelemetry.io/collector \
 		-dropreplace go.opentelemetry.io/collector/client \
 		-dropreplace go.opentelemetry.io/collector/component \
+		-dropreplace go.opentelemetry.io/collector/component/componentstatus \
 		-dropreplace go.opentelemetry.io/collector/config/configauth  \
 		-dropreplace go.opentelemetry.io/collector/config/configcompression  \
 		-dropreplace go.opentelemetry.io/collector/config/configgrpc  \

component/componentstatus/Makefile

@@ -0,0 +1 @@
+include ../../Makefile.Common

component/componentstatus/go.mod

@@ -0,0 +1,34 @@
+module go.opentelemetry.io/collector/component/componentstatus
+
+go 1.21.0
+
+require (
+	github.com/stretchr/testify v1.9.0
+	go.opentelemetry.io/collector/component v0.106.1
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/collector/config/configtelemetry v0.106.1 // indirect
+	go.opentelemetry.io/collector/pdata v1.12.0 // indirect
+	go.opentelemetry.io/otel v1.28.0 // indirect
+	go.opentelemetry.io/otel/metric v1.28.0 // indirect
+	go.opentelemetry.io/otel/trace v1.28.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	go.uber.org/zap v1.27.0 // indirect
+	golang.org/x/net v0.26.0 // indirect
+	golang.org/x/sys v0.21.0 // indirect
+	golang.org/x/text v0.16.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240528184218-531527333157 // indirect
+	google.golang.org/grpc v1.65.0 // indirect
+	google.golang.org/protobuf v1.34.2 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
+
+replace go.opentelemetry.io/collector/config/configtelemetry => ../../config/configtelemetry
+
+replace go.opentelemetry.io/collector/component => ../
+
+replace go.opentelemetry.io/collector/pdata => ../../pdata

component/componentstatus/instance.go

@@ -0,0 +1,16 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package componentstatus // import "go.opentelemetry.io/collector/component/componentstatus"
+
+import "go.opentelemetry.io/collector/component"
+
+// InstanceID uniquely identifies a component instance
+//
+// TODO: consider moving this struct to a new package/module like `extension/statuswatcher`
+// https://github.com/open-telemetry/opentelemetry-collector/issues/10764
+type InstanceID struct {
+	ID          component.ID
+	Kind        component.Kind
+	PipelineIDs map[component.ID]struct{}
+}

component/componentstatus/status.go

@@ -0,0 +1,139 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package componentstatus is an experimental module that defines how components should
+// report health statues, how collector hosts should facilitate component status reporting,
+// and how extensions should watch for new component statuses.
+//
+// This package is currently under development and is exempt from the Collector SIG's
+// breaking change policy.
+package componentstatus // import "go.opentelemetry.io/collector/component/componentstatus"
+
+import (
+	"time"
+)
+
+// 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.
+//
+// TODO: consider moving this interface to a new package/module like `extension/statuswatcher`
+// https://github.com/open-telemetry/opentelemetry-collector/issues/10764
+type Watcher interface {
+	// ComponentStatusChanged notifies about a change in the source component status.
+	// Extensions that implement this interface must be ready that the ComponentStatusChanged
+	// may be called before, after or concurrently with calls to Component.Start() and Component.Shutdown().
+	// The function may be called concurrently with itself.
+	ComponentStatusChanged(source *InstanceID, event *Event)
+}
+
+type Status int32
+
+// Enumeration of possible component statuses
+const (
+	// StatusNone indicates absence of component status.
+	StatusNone Status = iota
+	// StatusStarting indicates the component is starting.
+	StatusStarting
+	// StatusOK indicates the component is running without issues.
+	StatusOK
+	// StatusRecoverableError indicates that the component has experienced a transient error and may recover.
+	StatusRecoverableError
+	// StatusPermanentError indicates that the component has detected a condition at runtime that will need human intervention to fix. The collector will continue to run in a degraded mode.
+	StatusPermanentError
+	// StatusFatalError indicates that the collector has experienced a fatal runtime error and will shut down.
+	StatusFatalError
+	// StatusStopping indicates that the component is in the process of shutting down.
+	StatusStopping
+	// StatusStopped indicates that the component has completed shutdown.
+	StatusStopped
+)
+
+// String returns a string representation of a Status
+func (s Status) String() string {
+	switch s {
+	case StatusStarting:
+		return "StatusStarting"
+	case StatusOK:
+		return "StatusOK"
+	case StatusRecoverableError:
+		return "StatusRecoverableError"
+	case StatusPermanentError:
+		return "StatusPermanentError"
+	case StatusFatalError:
+		return "StatusFatalError"
+	case StatusStopping:
+		return "StatusStopping"
+	case StatusStopped:
+		return "StatusStopped"
+	}
+	return "StatusNone"
+}
+
+// Event contains a status and timestamp, and can contain an error
+type Event struct {
+	status Status
+	err    error
+	// TODO: consider if a timestamp is necessary in the default Event struct or is needed only for the healthcheckv2 extension
+	// https://github.com/open-telemetry/opentelemetry-collector/issues/10763
+	timestamp time.Time
+}
+
+// Status returns the Status (enum) associated with the Event
+func (ev *Event) Status() Status {
+	return ev.status
+}
+
+// Err returns the error associated with the Event.
+func (ev *Event) Err() error {
+	return ev.err
+}
+
+// Timestamp returns the timestamp associated with the Event
+func (ev *Event) Timestamp() time.Time {
+	return ev.timestamp
+}
+
+// NewEvent creates and returns a Event with the specified status and sets the timestamp
+// time.Now(). To set an error on the event for an error status use one of the dedicated
+// constructors (e.g. NewRecoverableErrorEvent, NewPermanentErrorEvent, NewFatalErrorEvent)
+func NewEvent(status Status) *Event {
+	return &Event{
+		status:    status,
+		timestamp: time.Now(),
+	}
+}
+
+// NewRecoverableErrorEvent wraps a transient error
+// passed as argument as a Event with a status StatusRecoverableError
+// and a timestamp set to time.Now().
+func NewRecoverableErrorEvent(err error) *Event {
+	ev := NewEvent(StatusRecoverableError)
+	ev.err = err
+	return ev
+}
+
+// NewPermanentErrorEvent wraps an error requiring human intervention to fix
+// passed as argument as a Event with a status StatusPermanentError
+// and a timestamp set to time.Now().
+func NewPermanentErrorEvent(err error) *Event {
+	ev := NewEvent(StatusPermanentError)
+	ev.err = err
+	return ev
+}
+
+// NewFatalErrorEvent wraps the fatal runtime error passed as argument as a Event
+// with a status StatusFatalError and a timestamp set to time.Now().
+func NewFatalErrorEvent(err error) *Event {
+	ev := NewEvent(StatusFatalError)
+	ev.err = err
+	return ev
+}
+
+// StatusIsError returns true for error statuses (e.g. StatusRecoverableError,
+// StatusPermanentError, or StatusFatalError)
+func StatusIsError(status Status) bool {
+	return status == StatusRecoverableError ||
+		status == StatusPermanentError ||
+		status == StatusFatalError
+}