[systemdreceiver] Add support for scraping unit status

.chloggen/systemd-receiver.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: new_component
+
+# The name of the component, or a single word describing the area of concern, (e.g. receiver/filelog)
+component: receiver/systemd
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Report active state of systemd units.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33532]
+
+# (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]

receiver/systemdreceiver/README.md

@@ -4,6 +4,7 @@
 | Status        |           |
 | ------------- |-----------|
 | Stability     | [development]: metrics   |
+| Unsupported Platforms | darwin, windows |
 | Distributions | [] |
 | Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Areceiver%2Fsystemd%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Areceiver%2Fsystemd) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Areceiver%2Fsystemd%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Areceiver%2Fsystemd) |
 | Code coverage | [![codecov](https://codecov.io/github/open-telemetry/opentelemetry-collector-contrib/graph/main/badge.svg?component=receiver_systemd)](https://app.codecov.io/gh/open-telemetry/opentelemetry-collector-contrib/tree/main/?components%5B0%5D=receiver_systemd&displayType=list) |
@@ -13,3 +14,27 @@
 [development]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#development
 <!-- end autogenerated section -->
 
+The systemd receiver gathers metrics for locally running systemd units.
+
+This scraper generates a metric with a label for service state with a value of `1` if the unit is in that state. For
+example, the following metrics will be generated if the `nginx` service is currently active:
+
+```
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="active"} = 1
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="reloading"} = 0
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="inactive"} = 0
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="failed"} = 0
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="activating"} = 0
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="deactivating"} = 0
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="maintenance"} = 0
+systemd.unit.state{systemd.unit.name="nginx", systemd.unit.active_state="refreshing"} = 0
+```
+
+## Configuration
+
+| Field   | Default          | Description                                                          |
+|---------| -----------------| ---------------------------------------------------------------------|
+| `scope` | `system`         | The service manager to gather units from, either `system` or `user`. |
+| `units` | `["*.service"]`  | The units to scrape, as a list of [patterns].                        |
+
+[patterns]: https://www.freedesktop.org/software/systemd/man/latest/systemctl.html#Parameter%20Syntax

receiver/systemdreceiver/config.go

@@ -3,4 +3,39 @@
 
 package systemdreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver"
 
-type Config struct{}
+import (
+	"errors"
+
+	"go.opentelemetry.io/collector/scraper/scraperhelper"
+	"go.uber.org/multierr"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver/internal/metadata"
+)
+
+var (
+	errInvalidScope = errors.New(`"scope" must be one of "systemd" or "user"`)
+	errNoUnits      = errors.New("no units configured")
+)
+
+type Config struct {
+	scraperhelper.ControllerConfig `mapstructure:",squash"`
+	metadata.MetricsBuilderConfig  `mapstructure:",squash"`
+
+	Scope string   `mapstructure:"scope"`
+	Units []string `mapstructure:"units"`
+}
+
+func (c Config) Validate() error {
+	var err error
+
+	// Ensure we have a valid scope.
+	if c.Scope != "system" && c.Scope != "user" {
+		err = multierr.Append(err, errInvalidScope)
+	}
+
+	if len(c.Units) == 0 {
+		err = multierr.Append(err, errNoUnits)
+	}
+
+	return err
+}

receiver/systemdreceiver/config_test.go

@@ -0,0 +1,54 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package systemdreceiver
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/scraper/scraperhelper"
+	"go.uber.org/multierr"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver/internal/metadata"
+)
+
+func TestValidate(t *testing.T) {
+	testCases := []struct {
+		desc        string
+		cfg         *Config
+		expectedErr error
+	}{
+		{
+			desc: "invalid scope",
+			cfg: &Config{
+				Scope:                "unknown",
+				Units:                []string{"*.service"},
+				ControllerConfig:     scraperhelper.NewDefaultControllerConfig(),
+				MetricsBuilderConfig: metadata.DefaultMetricsBuilderConfig(),
+			},
+			expectedErr: multierr.Combine(errInvalidScope),
+		},
+		{
+			desc: "no units",
+			cfg: &Config{
+				Scope:                "system",
+				Units:                []string{},
+				ControllerConfig:     scraperhelper.NewDefaultControllerConfig(),
+				MetricsBuilderConfig: metadata.DefaultMetricsBuilderConfig(),
+			},
+			expectedErr: multierr.Combine(errNoUnits),
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			actualErr := tc.cfg.Validate()
+			if tc.expectedErr != nil {
+				require.EqualError(t, actualErr, tc.expectedErr.Error())
+			} else {
+				require.NoError(t, actualErr)
+			}
+		})
+	}
+}

receiver/systemdreceiver/documentation.md

@@ -0,0 +1,33 @@
+[comment]: <> (Code generated by mdatagen. DO NOT EDIT.)
+
+# systemd
+
+## Default Metrics
+
+The following metrics are emitted by default. Each of them can be disabled by applying the following configuration:
+
+```yaml
+metrics:
+  <metric_name>:
+    enabled: false
+```
+
+### systemd.unit.state
+
+1 if the check resulted in active_state matching the current state, otherwise 0.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| 1 | Sum | Int | Cumulative | false |
+
+#### Attributes
+
+| Name | Description | Values | Requirement Level |
+| ---- | ----------- | ------ | -------- |
+| systemd.unit.active_state | The active state of the unit (https://www.freedesktop.org/software/systemd/man/latest/systemd.html#Units) | Str: ``active``, ``reloading``, ``inactive``, ``failed``, ``activating``, ``deactivating``, ``maintenance``, ``refreshing`` | Recommended |
+
+## Resource Attributes
+
+| Name | Description | Values | Enabled |
+| ---- | ----------- | ------ | ------- |
+| systemd.unit.name | Name of the systemd unit | Any Str | true |

receiver/systemdreceiver/factory.go

@@ -5,14 +5,24 @@ package systemdreceiver // import "github.com/open-telemetry/opentelemetry-colle
 
 import (
 	"context"
+	"errors"
+	"runtime"
+	"time"
 
 	"go.opentelemetry.io/collector/component"
 	"go.opentelemetry.io/collector/consumer"
 	"go.opentelemetry.io/collector/receiver"
+	"go.opentelemetry.io/collector/scraper"
+	"go.opentelemetry.io/collector/scraper/scraperhelper"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver/internal/metadata"
 )
 
+var (
+	errConfigNotValid = errors.New("config not valid for the systemd receiver")
+	errNonLinux       = errors.New("systemd receiver is only supported on Linux")
+)
+
 // NewFactory creates a factory for systemd receiver.
 func NewFactory() receiver.Factory {
 	return receiver.NewFactory(
@@ -22,14 +32,32 @@ func NewFactory() receiver.Factory {
 }
 
 func createDefaultConfig() component.Config {
-	return &Config{}
+	cfg := scraperhelper.NewDefaultControllerConfig()
+	cfg.CollectionInterval = 60 * time.Second
+
+	return &Config{
+		ControllerConfig:     cfg,
+		MetricsBuilderConfig: metadata.DefaultMetricsBuilderConfig(),
+		Scope:                "system",
+		Units:                []string{"*.service"},
+	}
 }
 
-func createMetricsReceiver(
-	_ context.Context,
-	_ receiver.Settings,
-	_ component.Config,
-	_ consumer.Metrics,
-) (receiver.Metrics, error) {
-	return systemdReceiver{}, nil
+func createMetricsReceiver(_ context.Context, params receiver.Settings, rConf component.Config, consumer consumer.Metrics) (receiver.Metrics, error) {
+	if runtime.GOOS != "linux" {
+		return nil, errNonLinux
+	}
+
+	cfg, ok := rConf.(*Config)
+	if !ok {
+		return nil, errConfigNotValid
+	}
+
+	systemdScraper := newScraper(cfg, params)
+	s, err := scraper.NewMetrics(systemdScraper.scrape, scraper.WithStart(systemdScraper.start), scraper.WithShutdown(systemdScraper.shutdown))
+	if err != nil {
+		return nil, err
+	}
+
+	return scraperhelper.NewMetricsController(&cfg.ControllerConfig, params, consumer, scraperhelper.AddScraper(metadata.Type, s))
 }

receiver/systemdreceiver/factory_test.go

@@ -0,0 +1,43 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package systemdreceiver
+
+import (
+	"runtime"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/receiver/receivertest"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver/internal/metadata"
+)
+
+func TestCreateDefaultConfig(t *testing.T) {
+	factory := NewFactory()
+	cfg := factory.CreateDefaultConfig()
+	assert.IsType(t, &Config{}, cfg)
+	assert.NotNil(t, cfg, "failed to create default config")
+	assert.NoError(t, componenttest.CheckConfigStruct(cfg))
+}
+
+func TestCreateMetrics(t *testing.T) {
+	factory := NewFactory()
+
+	scraper, err := factory.CreateMetrics(
+		t.Context(),
+		receivertest.NewNopSettings(metadata.Type),
+		factory.CreateDefaultConfig(),
+		nil,
+	)
+
+	if runtime.GOOS == "linux" {
+		assert.NoError(t, err)
+		assert.NotNil(t, scraper)
+	} else {
+		assert.Error(t, err)
+		assert.Equal(t, errNonLinux, err)
+		assert.Nil(t, scraper)
+	}
+}

receiver/systemdreceiver/go.mod

@@ -3,18 +3,29 @@ module github.com/open-telemetry/opentelemetry-collector-contrib/receiver/system
 go 1.24.0
 
 require (
+	github.com/godbus/dbus/v5 v5.1.0
+	github.com/google/go-cmp v0.7.0
+	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/golden v0.138.0
+	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest v0.133.0
 	github.com/stretchr/testify v1.11.1
 	go.opentelemetry.io/collector/component v1.44.1-0.20251021231522-c657d5d4e920
 	go.opentelemetry.io/collector/component/componenttest v0.138.1-0.20251021231522-c657d5d4e920
 	go.opentelemetry.io/collector/confmap v1.44.1-0.20251021231522-c657d5d4e920
 	go.opentelemetry.io/collector/consumer v1.44.1-0.20251021231522-c657d5d4e920
 	go.opentelemetry.io/collector/consumer/consumertest v0.138.1-0.20251021231522-c657d5d4e920
+	go.opentelemetry.io/collector/filter v0.138.1-0.20251021231522-c657d5d4e920
+	go.opentelemetry.io/collector/pdata v1.44.1-0.20251021231522-c657d5d4e920
 	go.opentelemetry.io/collector/receiver v1.44.1-0.20251021231522-c657d5d4e920
 	go.opentelemetry.io/collector/receiver/receivertest v0.138.1-0.20251021231522-c657d5d4e920
+	go.opentelemetry.io/collector/scraper v0.138.1-0.20251021231522-c657d5d4e920
+	go.opentelemetry.io/collector/scraper/scraperhelper v0.138.1-0.20251021231522-c657d5d4e920
 	go.uber.org/goleak v1.3.0
+	go.uber.org/multierr v1.11.0
+	go.uber.org/zap v1.27.0
 )
 
 require (
+	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
@@ -31,15 +42,16 @@ require (
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
+	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatautil v0.138.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
 	go.opentelemetry.io/collector/consumer/consumererror v0.138.1-0.20251021231522-c657d5d4e920 // indirect
 	go.opentelemetry.io/collector/consumer/xconsumer v0.138.1-0.20251021231522-c657d5d4e920 // indirect
 	go.opentelemetry.io/collector/featuregate v1.44.1-0.20251021231522-c657d5d4e920 // indirect
 	go.opentelemetry.io/collector/internal/telemetry v0.138.1-0.20251021231522-c657d5d4e920 // indirect
-	go.opentelemetry.io/collector/pdata v1.44.1-0.20251021231522-c657d5d4e920 // indirect
 	go.opentelemetry.io/collector/pdata/pprofile v0.138.1-0.20251021231522-c657d5d4e920 // indirect
 	go.opentelemetry.io/collector/pipeline v1.44.1-0.20251021231522-c657d5d4e920 // indirect
+	go.opentelemetry.io/collector/receiver/receiverhelper v0.138.1-0.20251021231522-c657d5d4e920 // indirect
 	go.opentelemetry.io/collector/receiver/xreceiver v0.138.1-0.20251021231522-c657d5d4e920 // indirect
 	go.opentelemetry.io/contrib/bridges/otelzap v0.13.0 // indirect
 	go.opentelemetry.io/otel v1.38.0 // indirect
@@ -48,8 +60,6 @@ require (
 	go.opentelemetry.io/otel/sdk v1.38.0 // indirect
 	go.opentelemetry.io/otel/sdk/metric v1.38.0 // indirect
 	go.opentelemetry.io/otel/trace v1.38.0 // indirect
-	go.uber.org/multierr v1.11.0 // indirect
-	go.uber.org/zap v1.27.0 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/net v0.42.0 // indirect
 	golang.org/x/sys v0.35.0 // indirect
@@ -65,3 +75,9 @@ retract (
 	v0.76.1
 	v0.65.0
 )
+
+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/pdatautil => ../../pkg/pdatautil