Document how to use OTLP exporters with self-signed certificates

exporters/otlp/otlplog/otlploggrpc/example_test.go

@@ -5,6 +5,12 @@ package otlploggrpc_test
 
 import (
 	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"os"
+
+	"google.golang.org/grpc/credentials"
 
 	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
 	"go.opentelemetry.io/otel/log/global"
@@ -31,3 +37,65 @@ func Example() {
 	// From here, the provider can be used by instrumentation to collect
 	// telemetry.
 }
+
+// Demonstrates how to configure the exporter using self-signed certificates.
+func Example_selfSignedCertificates() {
+	ctx := context.Background()
+	var grpcExpOpt []otlploggrpc.Option
+	// the filepath to the server's CA certificate
+	caFile := os.Getenv("CUSTOM_SERVER_CA_CERTIFICATE")
+	// the filepath to the client's certificate
+	clientCert := os.Getenv("CUSTOM_CLIENT_CERTIFICATE")
+	// the filepath to the client's private key
+	clientKey := os.Getenv("CUSTOM_CLIENT_KEY")
+	if caFile != "" && clientCert != "" && clientKey != "" {
+		// mTLS connection
+		tlsCfg := tls.Config{
+			InsecureSkipVerify: false,
+		}
+		// loads CA certificate
+		pool := x509.NewCertPool()
+		data, err := os.ReadFile(caFile)
+		if err != nil {
+			panic(err)
+		}
+		if !pool.AppendCertsFromPEM(data) {
+			panic(errors.New("failed to add CA certificate to root CA pool"))
+		}
+		tlsCfg.RootCAs = pool
+		// load client cert and key
+		keypair, err := tls.LoadX509KeyPair(clientCert, clientKey)
+		if err != nil {
+			panic(err)
+		}
+		tlsCfg.Certificates = []tls.Certificate{keypair}
+		creds := credentials.NewTLS(&tlsCfg)
+		option := otlploggrpc.WithTLSCredentials(creds)
+		grpcExpOpt = append(grpcExpOpt, option)
+	} else if caFile != "" {
+		// TLS connection
+		creds, err := credentials.NewClientTLSFromFile(caFile, "")
+		if err != nil {
+			panic(err)
+		}
+		option := otlploggrpc.WithTLSCredentials(creds)
+		grpcExpOpt = append(grpcExpOpt, option)
+	}
+	exp, err := otlploggrpc.New(ctx, grpcExpOpt...)
+	if err != nil {
+		panic(err)
+	}
+
+	processor := log.NewBatchProcessor(exp)
+	provider := log.NewLoggerProvider(log.WithProcessor(processor))
+	defer func() {
+		if err := provider.Shutdown(ctx); err != nil {
+			panic(err)
+		}
+	}()
+
+	global.SetLoggerProvider(provider)
+
+	// From here, the provider can be used by instrumentation to collect
+	// telemetry.
+}