[receiver/systemd] New receiver for systemd (#35822)

#### Description
Add a new receiver to handle systemd service state reporting as metrics.

<!-- Issue number (e.g. #1234) or full URL to issue, if applicable. -->
#### Link to tracking issue

#33532

.chloggen/initial_systemdreceiver.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. filelogreceiver)
+component: systemdreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Introduce the scaffolding of a new component, systemdreceiver
+
+# 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: []

.github/CODEOWNERS

@@ -295,6 +295,7 @@ receiver/sqlserverreceiver/                                         @open-teleme
 receiver/sshcheckreceiver/                                          @open-telemetry/collector-contrib-approvers @nslaughter @codeboten
 receiver/statsdreceiver/                                            @open-telemetry/collector-contrib-approvers @jmacd @dmitryax
 receiver/syslogreceiver/                                            @open-telemetry/collector-contrib-approvers @djaglowski @andrzej-stencel
+receiver/systemdreceiver/                                           @open-telemetry/collector-contrib-approvers @Hemansh31 @atoulme
 receiver/tcplogreceiver/                                            @open-telemetry/collector-contrib-approvers @djaglowski
 receiver/tlscheckreceiver/                                          @open-telemetry/collector-contrib-approvers @atoulme @michael-burt
 receiver/udplogreceiver/                                            @open-telemetry/collector-contrib-approvers @djaglowski

.github/ISSUE_TEMPLATE/bug_report.yaml

@@ -290,6 +290,7 @@ body:
       - receiver/sshcheck
       - receiver/statsd
       - receiver/syslog
+      - receiver/systemd
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -284,6 +284,7 @@ body:
       - receiver/sshcheck
       - receiver/statsd
       - receiver/syslog
+      - receiver/systemd
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

.github/ISSUE_TEMPLATE/other.yaml

@@ -284,6 +284,7 @@ body:
       - receiver/sshcheck
       - receiver/statsd
       - receiver/syslog
+      - receiver/systemd
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

.github/ISSUE_TEMPLATE/unmaintained.yaml

@@ -289,6 +289,7 @@ body:
       - receiver/sshcheck
       - receiver/statsd
       - receiver/syslog
+      - receiver/systemd
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

cmd/githubgen/allowlist.txt

@@ -23,4 +23,5 @@ m1rp
 jriguera
 abhishek-at-cloudwerx
 joker-star-l
-michael-burt
+michael-burt
+Hemansh31

receiver/systemdreceiver/Makefile

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

receiver/systemdreceiver/README.md

@@ -0,0 +1,13 @@
+# Systemd Receiver
+
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Stability     | [development]: metrics   |
+| 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 Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@Hemansh31](https://www.github.com/Hemansh31), [@atoulme](https://www.github.com/atoulme) |
+
+[development]: https://github.com/open-telemetry/opentelemetry-collector#development
+<!-- end autogenerated section -->
+

receiver/systemdreceiver/config.go

@@ -0,0 +1,6 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package systemdreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver"
+
+type Config struct{}

receiver/systemdreceiver/doc.go

@@ -0,0 +1,6 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:generate mdatagen metadata.yaml
+
+package systemdreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver"

receiver/systemdreceiver/factory.go

@@ -0,0 +1,35 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package systemdreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver"
+
+import (
+	"context"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/receiver"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver/internal/metadata"
+)
+
+// NewFactory creates a factory for systemd receiver.
+func NewFactory() receiver.Factory {
+	return receiver.NewFactory(
+		metadata.Type,
+		createDefaultConfig,
+		receiver.WithMetrics(createMetricsReceiver, metadata.MetricsStability))
+}
+
+func createDefaultConfig() component.Config {
+	return &Config{}
+}
+
+func createMetricsReceiver(
+	_ context.Context,
+	_ receiver.Settings,
+	_ component.Config,
+	_ consumer.Metrics,
+) (receiver.Metrics, error) {
+	return systemdReceiver{}, nil
+}

receiver/systemdreceiver/go.mod

@@ -0,0 +1,58 @@
+module github.com/open-telemetry/opentelemetry-collector-contrib/receiver/systemdreceiver
+
+go 1.22.0
+
+require (
+	github.com/stretchr/testify v1.9.0
+	go.opentelemetry.io/collector/component v0.111.1-0.20241008154146-ea48c09c31ae
+	go.opentelemetry.io/collector/confmap v1.17.1-0.20241008154146-ea48c09c31ae
+	go.opentelemetry.io/collector/consumer v0.111.1-0.20241008154146-ea48c09c31ae
+	go.opentelemetry.io/collector/consumer/consumertest v0.111.1-0.20241008154146-ea48c09c31ae
+	go.opentelemetry.io/collector/receiver v0.111.1-0.20241008154146-ea48c09c31ae
+	go.uber.org/goleak v1.3.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/go-viper/mapstructure/v2 v2.1.0 // indirect
+	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/knadh/koanf/maps v0.1.1 // indirect
+	github.com/knadh/koanf/providers/confmap v0.1.0 // indirect
+	github.com/knadh/koanf/v2 v2.1.1 // indirect
+	github.com/mitchellh/copystructure v1.2.0 // indirect
+	github.com/mitchellh/reflectwalk v1.0.2 // indirect
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/modern-go/reflect2 v1.0.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	go.opentelemetry.io/collector/config/configtelemetry v0.111.1-0.20241008154146-ea48c09c31ae // indirect
+	go.opentelemetry.io/collector/consumer/consumerprofiles v0.111.1-0.20241008154146-ea48c09c31ae // indirect
+	go.opentelemetry.io/collector/internal/globalsignal v0.111.1-0.20241008154146-ea48c09c31ae // indirect
+	go.opentelemetry.io/collector/pdata v1.17.1-0.20241008154146-ea48c09c31ae // indirect
+	go.opentelemetry.io/collector/pdata/pprofile v0.111.1-0.20241008154146-ea48c09c31ae // indirect
+	go.opentelemetry.io/collector/pipeline v0.111.1-0.20241008154146-ea48c09c31ae // indirect
+	go.opentelemetry.io/collector/receiver/receiverprofiles v0.111.1-0.20241008154146-ea48c09c31ae // indirect
+	go.opentelemetry.io/otel v1.31.0 // indirect
+	go.opentelemetry.io/otel/metric v1.31.0 // indirect
+	go.opentelemetry.io/otel/sdk v1.31.0 // indirect
+	go.opentelemetry.io/otel/sdk/metric v1.31.0 // indirect
+	go.opentelemetry.io/otel/trace v1.31.0 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	go.uber.org/zap v1.27.0 // indirect
+	golang.org/x/net v0.28.0 // indirect
+	golang.org/x/sys v0.26.0 // indirect
+	golang.org/x/text v0.19.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240822170219-fc7c04adadcd // indirect
+	google.golang.org/grpc v1.67.1 // indirect
+	google.golang.org/protobuf v1.35.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
+
+retract (
+	v0.76.2
+	v0.76.1
+	v0.65.0
+)