[mongodbreceiver] change 'Hosts' configuration type (#32550)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
what changed：mongodbreceiver `Hosts` configuration use
`confignet.TCPAddrConfig`.

Hi master, I looked at the mongodbreceiver code: 

1. The error is caused by
[AddrConfig.Validate()](https://github.com/open-telemetry/opentelemetry-collector/blob/main/config/confignet/confignet.go#L122)
return error.
```go
func (na *AddrConfig) Validate() error {
	switch na.Transport {
	case TransportTypeTCP,
		...
		return nil
	default:
		return fmt.Errorf("invalid transport type %q", na.Transport)
	}
}
```

2. `mongodbreceiver` use
[go.mongodb.org/mongo-driver](https://github.com/mongodb/mongo-go-driver)to
connect mongodb.


https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/mongodbreceiver/go.mod#L13
```go
module github.com/open-telemetry/opentelemetry-collector-contrib/receiver/mongodbreceiver

go 1.21

require (
	...
	go.mongodb.org/mongo-driver v1.15.0
	...
)
```


3. `go.mongodb.org/mongo-driver` based on `TCP`.


https://github.com/mongodb/mongo-go-driver/blob/v1/x/mongo/driver/dns/dns.go#L82
```go
_, addresses, err := r.LookupSRV(srvName, "tcp", host)
```

So I think mongodbreceiver only supporting TCP.

**Link to tracking Issue:** <Issue number if applicable>

#32199

---------

Co-authored-by: Tyler Helmuth <[email protected]>
Co-authored-by: Daniel Jaglowski <[email protected]>
Co-authored-by: Curtis Robert <[email protected]>

.chloggen/fix-mongodbreceiver-hosts.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: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: mongodbreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Now only supports `TCP` connections
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [32199]
+
+# (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: This fixes a bug where hosts had to explicitly set `tcp` as the transport type. The `transport` option has been removed.
+
+# 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: []

receiver/mongodbreceiver/README.md

@@ -33,7 +33,7 @@ Mongodb recommends to set up a least privilege user (LPU) with a [`clusterMonito
 
 The following settings are optional:
 
-- `hosts` (default: [`localhost:27017`]): list of `host:port` or unix domain socket endpoints.
+- `hosts` (default: [`localhost:27017`]): list of `host:port` or unix domain socket endpoints.The `transport` option is no longer available.
   - For standalone MongoDB deployments this is the hostname and port of the mongod instance
   - For replica sets specify the hostnames and ports of the mongod instances that are in the replica set configuration. If the `replica_set` field is specified, nodes will be autodiscovered.
   - For a sharded MongoDB deployment, please specify a list of the `mongos` hosts.
@@ -52,7 +52,6 @@ receivers:
   mongodb:
     hosts:
       - endpoint: localhost:27017
-        transport: tcp
     username: otel
     password: ${env:MONGODB_PASSWORD}
     collection_interval: 60s

receiver/mongodbreceiver/config.go

@@ -25,11 +25,12 @@ type Config struct {
 	configtls.ClientConfig         `mapstructure:"tls,omitempty"`
 	// MetricsBuilderConfig defines which metrics/attributes to enable for the scraper
 	metadata.MetricsBuilderConfig `mapstructure:",squash"`
-	Hosts                         []confignet.AddrConfig `mapstructure:"hosts"`
-	Username                      string                 `mapstructure:"username"`
-	Password                      configopaque.String    `mapstructure:"password"`
-	ReplicaSet                    string                 `mapstructure:"replica_set,omitempty"`
-	Timeout                       time.Duration          `mapstructure:"timeout"`
+	// Deprecated - Transport option will be removed in v0.102.0
+	Hosts      []confignet.TCPAddrConfig `mapstructure:"hosts"`
+	Username   string                    `mapstructure:"username"`
+	Password   configopaque.String       `mapstructure:"password"`
+	ReplicaSet string                    `mapstructure:"replica_set,omitempty"`
+	Timeout    time.Duration             `mapstructure:"timeout"`
 }
 
 func (c *Config) Validate() error {

receiver/mongodbreceiver/config_test.go

@@ -76,12 +76,11 @@ func TestValidate(t *testing.T) {
 	}
 	for _, tc := range testCases {
 		t.Run(tc.desc, func(t *testing.T) {
-			var hosts []confignet.AddrConfig
+			var hosts []confignet.TCPAddrConfig
 
 			for _, ep := range tc.endpoints {
-				hosts = append(hosts, confignet.AddrConfig{
-					Endpoint:  ep,
-					Transport: confignet.TransportTypeTCP,
+				hosts = append(hosts, confignet.TCPAddrConfig{
+					Endpoint: ep,
 				})
 			}
 
@@ -135,10 +134,9 @@ func TestBadTLSConfigs(t *testing.T) {
 			cfg := &Config{
 				Username: "otel",
 				Password: "pword",
-				Hosts: []confignet.AddrConfig{
+				Hosts: []confignet.TCPAddrConfig{
 					{
-						Endpoint:  "localhost:27017",
-						Transport: confignet.TransportTypeTCP,
+						Endpoint: "localhost:27017",
 					},
 				},
 				ControllerConfig: scraperhelper.NewDefaultControllerConfig(),
@@ -156,7 +154,7 @@ func TestBadTLSConfigs(t *testing.T) {
 
 func TestOptions(t *testing.T) {
 	cfg := &Config{
-		Hosts: []confignet.AddrConfig{
+		Hosts: []confignet.TCPAddrConfig{
 			{
 				Endpoint: "localhost:27017",
 			},
@@ -181,7 +179,7 @@ func TestOptionsTLS(t *testing.T) {
 	caFile := filepath.Join("testdata", "certs", "ca.crt")
 
 	cfg := &Config{
-		Hosts: []confignet.AddrConfig{
+		Hosts: []confignet.TCPAddrConfig{
 			{
 				Endpoint: "localhost:27017",
 			},
@@ -209,7 +207,7 @@ func TestLoadConfig(t *testing.T) {
 	require.NoError(t, sub.Unmarshal(cfg))
 
 	expected := factory.CreateDefaultConfig().(*Config)
-	expected.Hosts = []confignet.AddrConfig{
+	expected.Hosts = []confignet.TCPAddrConfig{
 		{
 			Endpoint: "localhost:27017",
 		},

receiver/mongodbreceiver/factory.go

@@ -29,10 +29,9 @@ func createDefaultConfig() component.Config {
 	return &Config{
 		ControllerConfig: scraperhelper.NewDefaultControllerConfig(),
 		Timeout:          time.Minute,
-		Hosts: []confignet.AddrConfig{
+		Hosts: []confignet.TCPAddrConfig{
 			{
-				Endpoint:  "localhost:27017",
-				Transport: confignet.TransportTypeTCP,
+				Endpoint: "localhost:27017",
 			},
 		},
 		MetricsBuilderConfig: metadata.DefaultMetricsBuilderConfig(),

receiver/mongodbreceiver/integration_test.go

@@ -56,7 +56,7 @@ func integrationTest(name string, script []string, cfgMod func(*Config)) func(*t
 				cfgMod(rCfg)
 				rCfg.CollectionInterval = 2 * time.Second
 				rCfg.MetricsBuilderConfig.Metrics.MongodbLockAcquireTime.Enabled = false
-				rCfg.Hosts = []confignet.AddrConfig{
+				rCfg.Hosts = []confignet.TCPAddrConfig{
 					{
 						Endpoint: fmt.Sprintf("%s:%s", ci.Host(t), ci.MappedPort(t, mongoPort)),
 					},