[exporter/loki] Add Config QueueSettings validation (#16855)

Description: Added QueueStettings validation into Config Validate method
Link to tracking Issue: #7841

.chloggen/lokiexporter-add-queue-settings-validate.yaml

@@ -0,0 +1,16 @@
+# 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: lokiexporter
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Added QueueSettings validation into Config Validate method
+
+# One or more tracking issues related to the change
+issues: [7841]
+
+# (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:

exporter/lokiexporter/config.go

@@ -51,6 +51,10 @@ type Config struct {
 }
 
 func (c *Config) Validate() error {
+	if err := c.QueueSettings.Validate(); err != nil {
+		return fmt.Errorf("queue settings has invalid configuration: %w", err)
+	}
+
 	if _, err := url.Parse(c.Endpoint); c.Endpoint == "" || err != nil {
 		return fmt.Errorf("\"endpoint\" must be a valid URL")
 	}

exporter/lokiexporter/config_test.go

@@ -15,6 +15,7 @@
 package lokiexporter
 
 import (
+	"fmt"
 	"path/filepath"
 	"testing"
 	"time"
@@ -164,3 +165,43 @@ func TestIsLegacy(t *testing.T) {
 func stringp(str string) *string {
 	return &str
 }
+
+func TestConfigValidate(t *testing.T) {
+	testCases := []struct {
+		desc string
+		cfg  *Config
+		err  error
+	}{
+		{
+			desc: "QueueSettings are invalid",
+			cfg:  &Config{QueueSettings: exporterhelper.QueueSettings{QueueSize: -1, Enabled: true}},
+			err:  fmt.Errorf("queue settings has invalid configuration"),
+		},
+		{
+			desc: "Endpoint is invalid",
+			cfg:  &Config{},
+			err:  fmt.Errorf("\"endpoint\" must be a valid URL"),
+		},
+		{
+			desc: "Config is valid",
+			cfg: &Config{
+				HTTPClientSettings: confighttp.HTTPClientSettings{
+					Endpoint: "https://loki.example.com",
+				},
+			},
+			err: nil,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			err := tc.cfg.Validate()
+			if tc.err != nil {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), tc.err.Error())
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}