[receiver/hostmetrics] add EntityState entity event as log record for…

… host (open-telemetry#33928)

**Description:** 
Add EntityState event for host, implementation is similiar to
k8sclusterreceiver. This change sends empty event, which can be used
together with resourcedetection processor to add required attributes:
```
    receivers:
      hostmetrics:
        enabled: true
        metadata_collection_interval: "5m"

    processors:
      resourcedetection/env:
        detectors: ["system", "env"]
        timeout: 2s
        override: false
        system:
          resource_attributes:
            host.id:
              enabled: true
      resourcedetection/region:
        detectors: ["gcp", "ec2", "azure"]
        timeout: 2s
        override: true
      transform/entity-event:
        log_statements:
          - context: log
            statements:
              - set(attributes["otel.entity.attributes"]["otel.entity.id"]["host.id"], resource.attributes["host.id"])
              - set(attributes["otel.entity.attributes"]["host.name"], resource.attributes["host.name"])
              - set(attributes["otel.entity.attributes"]["host.type"], resource.attributes["host.type"])
              - set(attributes["otel.entity.attributes"]["host.image.id"], resource.attributes["host.image.id"])
              - set(attributes["otel.entity.attributes"]["host.image.name"], resource.attributes["host.image.name"])
          - context: resource
            statements:
              - keep_keys(attributes, [""])
    service:
      pipelines:
        logs/entity:
          exporters:
            - otlp
          processors:
            - k8sattributes
            - resourcedetection/env
            - resourcedetection/region
            - transform/entity-event
          receivers:
            - hostmetrics
```

**Link to tracking Issue:**
open-telemetry#33927

**Testing:**
- kind cluster
- unit tests

**Documentation:** <Describe the documentation added.>
- added docs

---------

Co-authored-by: Tigran Najaryan <[email protected]>
Co-authored-by: Dmitrii Anoshin <[email protected]>

.chloggen/entity-event.yaml

@@ -0,0 +1,27 @@
+# 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. filelogreceiver)
+component: hostmetricsreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "allow configuring log pipeline to send host EntityState event"
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33927]
+
+# (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:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# 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: [user]

connector/datadogconnector/go.mod

@@ -345,3 +345,5 @@ replace github.com/open-telemetry/opentelemetry-collector-contrib/processor/tran
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/sampling => ../../pkg/sampling
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/internal/pdatautil => ../../internal/pdatautil
+
+replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/experimentalmetricmetadata => ../../pkg/experimentalmetricmetadata

exporter/datadogexporter/go.mod

@@ -257,6 +257,7 @@ require (
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/docker v0.105.0 // indirect
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/filter v0.105.0 // indirect
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/pdatautil v0.105.0 // indirect
+	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/experimentalmetricmetadata v0.0.0-00010101000000-000000000000 // indirect
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/ottl v0.105.0 // indirect
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatautil v0.105.0 // indirect
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/sampling v0.105.0 // indirect
@@ -445,3 +446,5 @@ replace github.com/open-telemetry/opentelemetry-collector-contrib/processor/tran
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/sampling => ../../pkg/sampling
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/internal/pdatautil => ../../internal/pdatautil
+
+replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/experimentalmetricmetadata => ../../pkg/experimentalmetricmetadata

exporter/datadogexporter/integrationtest/go.mod

@@ -355,3 +355,5 @@ replace github.com/open-telemetry/opentelemetry-collector-contrib/processor/tran
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/sampling => ../../../pkg/sampling
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/internal/pdatautil => ../../../internal/pdatautil
+
+replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/experimentalmetricmetadata => ../../../pkg/experimentalmetricmetadata

receiver/hostmetricsreceiver/README.md

@@ -3,19 +3,21 @@
 <!-- status autogenerated section -->
 | Status        |           |
 | ------------- |-----------|
-| Stability     | [beta]: metrics   |
+| Stability     | [development]: logs   |
+|               | [beta]: metrics   |
 | Distributions | [core], [contrib] |
 | Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Areceiver%2Fhostmetrics%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Areceiver%2Fhostmetrics) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Areceiver%2Fhostmetrics%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Areceiver%2Fhostmetrics) |
 | [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@dmitryax](https://www.github.com/dmitryax), [@braydonk](https://www.github.com/braydonk) |
 
+[development]: https://github.com/open-telemetry/opentelemetry-collector#development
 [beta]: https://github.com/open-telemetry/opentelemetry-collector#beta
 [core]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol
 [contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
 <!-- end autogenerated section -->
 
 The Host Metrics receiver generates metrics about the host system scraped
-from various sources. This is intended to be used when the collector is
-deployed as an agent.
+from various sources and host entity event as log. This is intended to be 
+used when the collector is deployed as an agent.
 
 ## Getting Started
 
@@ -188,6 +190,9 @@ Currently, the hostmetrics receiver does not set any Resource attributes on the
 ```
 export OTEL_RESOURCE_ATTRIBUTES="service.name=<the name of your service>,service.namespace=<the namespace of your service>,service.instance.id=<uuid of the instance>"
 ```
+## Entity Events
+
+**Entity Events as logs are experimental** and might eventually be replaced by the result of [the OTEP](https://github.com/open-telemetry/oteps/blob/main/text/entities/0256-entities-data-model.md#entity-events). For now, the hostmetrics receiver can send the host entity event as a log records. By default, the hostmetrics receiver sends periodic EntityState events every 5 minutes. You can change that by setting `metadata_collection_interval`. Entity Events as logs are experimental. The result of the OTEP might eventually replace that.
 
 ## Feature Gates
 

receiver/hostmetricsreceiver/config.go

@@ -6,6 +6,7 @@ package hostmetricsreceiver // import "github.com/open-telemetry/opentelemetry-c
 import (
 	"errors"
 	"fmt"
+	"time"
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/confmap"
@@ -25,6 +26,13 @@ type Config struct {
 	Scrapers                       map[string]internal.Config `mapstructure:"-"`
 	// RootPath is the host's root directory (linux only).
 	RootPath string `mapstructure:"root_path"`
+
+	// Collection interval for metadata.
+	// Metadata of the particular entity is collected when the entity changes.
+	// In addition metadata of all entities is collected periodically even if no changes happen.
+	// Setting the duration to 0 will disable periodic collection (however will not impact
+	// metadata collection on changes).
+	MetadataCollectionInterval time.Duration `mapstructure:"metadata_collection_interval"`
 }
 
 var _ component.Config = (*Config)(nil)

receiver/hostmetricsreceiver/config_test.go

@@ -58,6 +58,7 @@ func TestLoadConfig(t *testing.T) {
 
 	r1 := cfg.Receivers[component.NewIDWithName(metadata.Type, "customname")].(*Config)
 	expectedConfig := &Config{
+		MetadataCollectionInterval: 5 * time.Minute,
 		ControllerConfig: scraperhelper.ControllerConfig{
 			CollectionInterval: 30 * time.Second,
 			InitialDelay:       time.Second,

receiver/hostmetricsreceiver/factory.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"time"
 
 	"github.com/shirou/gopsutil/v4/host"
 	"github.com/shirou/gopsutil/v4/process"
@@ -28,6 +29,10 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/hostmetricsreceiver/internal/scraper/processscraper"
 )
 
+const (
+	defaultMetadataCollectionInterval = 5 * time.Minute
+)
+
 // This file implements Factory for HostMetrics receiver.
 var (
 	scraperFactories = map[string]internal.ScraperFactory{
@@ -48,7 +53,8 @@ func NewFactory() receiver.Factory {
 	return receiver.NewFactory(
 		metadata.Type,
 		createDefaultConfig,
-		receiver.WithMetrics(createMetricsReceiver, metadata.MetricsStability))
+		receiver.WithMetrics(createMetricsReceiver, metadata.MetricsStability),
+		receiver.WithLogs(createLogsReceiver, metadata.LogsStability))
 }
 
 func getScraperFactory(key string) (internal.ScraperFactory, bool) {
@@ -61,7 +67,10 @@ func getScraperFactory(key string) (internal.ScraperFactory, bool) {
 
 // createDefaultConfig creates the default configuration for receiver.
 func createDefaultConfig() component.Config {
-	return &Config{ControllerConfig: scraperhelper.NewDefaultControllerConfig()}
+	return &Config{
+		ControllerConfig:           scraperhelper.NewDefaultControllerConfig(),
+		MetadataCollectionInterval: defaultMetadataCollectionInterval,
+	}
 }
 
 // createMetricsReceiver creates a metrics receiver based on provided config.
@@ -89,6 +98,16 @@ func createMetricsReceiver(
 	)
 }
 
+func createLogsReceiver(
+	_ context.Context, set receiver.Settings, cfg component.Config, consumer consumer.Logs,
+) (receiver.Logs, error) {
+	return &hostEntitiesReceiver{
+		cfg:      cfg.(*Config),
+		nextLogs: consumer,
+		settings: &set,
+	}, nil
+}
+
 func createAddScraperOptions(
 	ctx context.Context,
 	set receiver.Settings,

receiver/hostmetricsreceiver/factory_test.go

@@ -39,8 +39,8 @@ func TestCreateReceiver(t *testing.T) {
 	assert.NotNil(t, mReceiver)
 
 	tLogs, err := factory.CreateLogsReceiver(context.Background(), creationSet, cfg, consumertest.NewNop())
-	assert.Equal(t, err, component.ErrDataTypeIsNotSupported)
-	assert.Nil(t, tLogs)
+	assert.NoError(t, err)
+	assert.NotNil(t, tLogs)
 }
 
 func TestCreateReceiver_ScraperKeyConfigError(t *testing.T) {

receiver/hostmetricsreceiver/go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/google/go-cmp v0.6.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal v0.105.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/filter v0.105.0
+	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/experimentalmetricmetadata v0.0.0-00010101000000-000000000000
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest v0.105.0
 	github.com/prometheus-community/windows_exporter v0.25.1
 	github.com/prometheus/procfs v0.15.1
@@ -21,8 +22,6 @@ require (
 	go.opentelemetry.io/collector/pdata v1.12.1-0.20240716231837-5753a58f712b
 	go.opentelemetry.io/collector/receiver v0.105.1-0.20240717163034-43ed6184f9fe
 	go.opentelemetry.io/collector/semconv v0.105.1-0.20240717163034-43ed6184f9fe
-	go.opentelemetry.io/otel/metric v1.28.0
-	go.opentelemetry.io/otel/trace v1.28.0
 	go.uber.org/goleak v1.3.0
 	go.uber.org/multierr v1.11.0
 	go.uber.org/zap v1.27.0
@@ -128,9 +127,11 @@ require (
 	go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v1.28.0 // indirect
 	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.28.0 // indirect
 	go.opentelemetry.io/otel/log v0.4.0 // indirect
+	go.opentelemetry.io/otel/metric v1.28.0 // indirect
 	go.opentelemetry.io/otel/sdk v1.28.0 // indirect
 	go.opentelemetry.io/otel/sdk/log v0.4.0 // indirect
 	go.opentelemetry.io/otel/sdk/metric v1.28.0 // indirect
+	go.opentelemetry.io/otel/trace v1.28.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.3.1 // indirect
 	golang.org/x/crypto v0.25.0 // indirect
 	golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 // indirect
@@ -164,3 +165,5 @@ replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatautil
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest => ../../pkg/pdatatest
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/golden => ../../pkg/golden
+
+replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/experimentalmetricmetadata => ../../pkg/experimentalmetricmetadata

receiver/hostmetricsreceiver/metadata.yaml

@@ -5,6 +5,7 @@ status:
   class: receiver
   stability:
     beta: [metrics]
+    development: [logs]
   distributions: [core, contrib]
   codeowners:
     active: [dmitryax, braydonk]