[receiver/tcpcheck] New receiver

#### Description
Introduce a new receiver, TCP Check Receiver.This receiver creates stats by connecting to an TCP server.

#### Link to tracking issue
Related to open-telemetry#34414

#### Testing
N/A

#### Documentation
metadata.yaml, README.

Signed-off-by: huangyanfeng <huangyanfeng1992@gmail.com>

.chloggen/tcp-checker.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: tcpcheckerreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Introducing new component tcpchecker receiver
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [34414]
+
+# (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/ISSUE_TEMPLATE/bug_report.yaml

@@ -292,6 +292,7 @@ body:
       - receiver/statsd
       - receiver/syslog
       - receiver/systemd
+      - receiver/tcpcheck
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

.github/ISSUE_TEMPLATE/feature_request.yaml

@@ -286,6 +286,7 @@ body:
       - receiver/statsd
       - receiver/syslog
       - receiver/systemd
+      - receiver/tcpcheck
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

.github/ISSUE_TEMPLATE/other.yaml

@@ -286,6 +286,7 @@ body:
       - receiver/statsd
       - receiver/syslog
       - receiver/systemd
+      - receiver/tcpcheck
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

.github/ISSUE_TEMPLATE/unmaintained.yaml

@@ -291,6 +291,7 @@ body:
       - receiver/statsd
       - receiver/syslog
       - receiver/systemd
+      - receiver/tcpcheck
       - receiver/tcplog
       - receiver/tlscheck
       - receiver/udplog

receiver/tcpcheckreceiver/Makefile

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

receiver/tcpcheckreceiver/README.md

@@ -0,0 +1,44 @@
+# TCP Check Receiver
+
+<!-- status autogenerated section -->
+| Status        |           |
+| ------------- |-----------|
+| Stability     | [alpha]: metrics   |
+| Distributions | [contrib] |
+| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Areceiver%2Ftcpcheck%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Areceiver%2Ftcpcheck) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Areceiver%2Ftcpcheck%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Areceiver%2Ftcpcheck) |
+| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@atoulme](https://www.github.com/atoulme), [@yanfeng1992](https://www.github.com/yanfeng1992) |
+
+[alpha]: https://github.com/open-telemetry/opentelemetry-collector#alpha
+[contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
+<!-- end autogenerated section -->
+
+This receiver creates stats by connecting to an TCP server.
+
+
+## Configuration
+
+The following settings are required:
+- `endpoint`
+
+
+
+The following settings are optional:
+
+- `collection_interval` (default = `60s`): This receiver collects metrics on an interval. Valid time units are `ns`, `us` (or `µs`), `ms`, `s`, `m`, `h`.
+
+
+### Example Configuration
+
+```yaml
+receivers:
+  sshcheck:
+    endpoint: localhost:80
+    collection_interval: 60s
+```
+
+The full list of settings exposed for this receiver are documented [here](./config.go) with detailed sample configurations [here](./testdata/config.yaml). 
+
+## Metrics
+
+Details about the metrics produced by this receiver can be found in [metadata.yaml](./metadata.yaml)
+

receiver/tcpcheckreceiver/config.go

@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package tcpcheckreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver"
+
+import (
+	"errors"
+	"net"
+	"strings"
+
+	"go.opentelemetry.io/collector/receiver/scraperhelper"
+	"go.uber.org/multierr"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver/internal/configtcp"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver/internal/metadata"
+)
+
+// Predefined error responses for configuration validation failures
+var (
+	errMissingEndpoint   = errors.New(`"endpoint" not specified in config`)
+	errInvalidEndpoint   = errors.New(`"endpoint" is invalid`)
+	errConfigNotTCPCheck = errors.New("config was not a TCP check receiver config")
+)
+
+type Config struct {
+	scraperhelper.ControllerConfig `mapstructure:",squash"`
+	configtcp.TCPClientSettings    `mapstructure:",squash"`
+	MetricsBuilderConfig           metadata.MetricsBuilderConfig `mapstructure:",squash"`
+}
+
+func (c Config) Validate() (err error) {
+	if c.TCPClientSettings.Endpoint == "" {
+		err = multierr.Append(err, errMissingEndpoint)
+	} else if strings.Contains(c.TCPClientSettings.Endpoint, " ") {
+		err = multierr.Append(err, errInvalidEndpoint)
+	} else if _, _, splitErr := net.SplitHostPort(c.TCPClientSettings.Endpoint); splitErr != nil {
+		err = multierr.Append(splitErr, errInvalidEndpoint)
+	}
+	return
+}

receiver/tcpcheckreceiver/config_test.go

@@ -0,0 +1,105 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package tcpcheckreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver"
+
+import (
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/confmap/confmaptest"
+	"go.opentelemetry.io/collector/receiver/scraperhelper"
+	"go.uber.org/multierr"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver/internal/configtcp"
+)
+
+// check that OTel Collector patterns are implemented
+func TestCheckConfig(t *testing.T) {
+	t.Parallel()
+	if err := componenttest.CheckConfigStruct(&Config{}); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// test the validate function for config
+func TestValidate(t *testing.T) {
+	t.Parallel()
+	testCases := []struct {
+		desc        string
+		cfg         *Config
+		expectedErr error
+	}{
+		{
+			desc: "missing endpoint",
+			cfg: &Config{
+				TCPClientSettings: configtcp.TCPClientSettings{
+					Endpoint: "",
+				},
+				ControllerConfig: scraperhelper.NewDefaultControllerConfig(),
+			},
+			expectedErr: multierr.Combine(errMissingEndpoint),
+		},
+		{
+			desc: "invalid endpoint",
+			cfg: &Config{
+				TCPClientSettings: configtcp.TCPClientSettings{
+					Endpoint: "badendpoint . cuz spaces:443",
+				},
+				ControllerConfig: scraperhelper.NewDefaultControllerConfig(),
+			},
+			expectedErr: multierr.Combine(errInvalidEndpoint),
+		},
+		{
+			desc: "no error",
+			cfg: &Config{
+				TCPClientSettings: configtcp.TCPClientSettings{
+					Endpoint: "localhost:8080",
+				},
+				ControllerConfig: scraperhelper.NewDefaultControllerConfig(),
+			},
+			expectedErr: error(nil),
+		},
+	}
+	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)
+			}
+		})
+	}
+}
+
+func TestLoadConfig(t *testing.T) {
+	// load test config
+	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+	require.NoError(t, err)
+	rcvrs, err := cm.Sub("receivers")
+	require.NoError(t, err)
+	tcpconf, err := rcvrs.Sub("tcpcheck")
+	require.NoError(t, err)
+	// unmarshal to receiver config
+	actualConfig, ok := NewFactory().CreateDefaultConfig().(*Config)
+	require.True(t, ok)
+	require.NoError(t, tcpconf.Unmarshal(actualConfig))
+
+	// set expected config
+	expectedConfig, ok := NewFactory().CreateDefaultConfig().(*Config)
+	require.True(t, ok)
+
+	expectedConfig.ControllerConfig = scraperhelper.ControllerConfig{
+		InitialDelay:       time.Second,
+		CollectionInterval: 60 * time.Second,
+	}
+	expectedConfig.TCPClientSettings = configtcp.TCPClientSettings{
+		Endpoint: "localhost:80",
+		Timeout:  10 * time.Second,
+	}
+	require.Equal(t, expectedConfig, actualConfig)
+}

receiver/tcpcheckreceiver/doc.go

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

receiver/tcpcheckreceiver/documentation.md

@@ -0,0 +1,56 @@
+[comment]: <> (Code generated by mdatagen. DO NOT EDIT.)
+
+# tcpcheck
+
+## 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
+```
+
+### tcpcheck.duration
+
+Measures the duration of TCP connection.
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| ns | Gauge | Int |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| tcp.endpoint | Full TCO endpoint | Any Str |
+
+### tcpcheck.error
+
+Records errors occurring during TCP check.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| {error} | Sum | Int | Cumulative | true |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| tcp.endpoint | Full TCO endpoint | Any Str |
+| error.message | Error message recorded during check | Any Str |
+
+### tcpcheck.status
+
+1 if the TCP client successfully connected, otherwise 0.
+
+| Unit | Metric Type | Value Type |
+| ---- | ----------- | ---------- |
+| 1 | Gauge | Int |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| tcp.endpoint | Full TCO endpoint | Any Str |

receiver/tcpcheckreceiver/factory.go

@@ -0,0 +1,53 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package tcpcheckreceiver // import "github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver"
+
+import (
+	"context"
+	"time"
+
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/consumer"
+	"go.opentelemetry.io/collector/receiver"
+	"go.opentelemetry.io/collector/receiver/scraperhelper"
+
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver/internal/configtcp"
+	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/tcpcheckreceiver/internal/metadata"
+)
+
+// NewFactory creates a factory for tcpcheckreceiver receiver.
+func NewFactory() receiver.Factory {
+	return receiver.NewFactory(
+		metadata.Type,
+		createDefaultConfig,
+		receiver.WithMetrics(createMetricsReceiver, metadata.MetricsStability))
+}
+
+func createDefaultConfig() component.Config {
+	cfg := scraperhelper.NewDefaultControllerConfig()
+	cfg.CollectionInterval = 10 * time.Second
+
+	return &Config{
+		ControllerConfig: cfg,
+		TCPClientSettings: configtcp.TCPClientSettings{
+			Timeout: 10 * time.Second,
+		},
+		MetricsBuilderConfig: metadata.DefaultMetricsBuilderConfig(),
+	}
+}
+
+func createMetricsReceiver(_ context.Context, params receiver.Settings, rConf component.Config, consumer consumer.Metrics) (receiver.Metrics, error) {
+	cfg, ok := rConf.(*Config)
+	if !ok {
+		return nil, errConfigNotTCPCheck
+	}
+
+	tcpCheckScraper := newScraper(cfg, params)
+	scraper, err := scraperhelper.NewScraper(metadata.Type, tcpCheckScraper.scrape, scraperhelper.WithStart(tcpCheckScraper.start))
+	if err != nil {
+		return nil, err
+	}
+
+	return scraperhelper.NewScraperControllerReceiver(&cfg.ControllerConfig, params, consumer, scraperhelper.AddScraper(scraper))
+}