config: add support for extra configuration

.golangci.yml

@@ -70,6 +70,11 @@ issues:
         - gosec
         - perfsprint
         - usestdlibvars
+    # Ignoring gosec G402: TLS MinVersion too low
+    # as the https://pkg.go.dev/crypto/tls#Config handles MinVersion default well.
+    - text: "G402: TLS MinVersion too low."
+      linters:
+        - gosec
   include:
     # revive exported should have comment or be unexported.
     - EXC0012

CHANGELOG.md

@@ -12,6 +12,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 - Added support for providing `endpoint`, `pollingIntervalMs` and `initialSamplingRate` using environment variable `OTEL_TRACES_SAMPLER_ARG` in `go.opentelemetry.io/contrib/samples/jaegerremote`. (#6310)
 - Added support exporting logs via OTLP over gRPC in `go.opentelemetry.io/contrib/config`. (#6340)
+- Added support for configuring `Certificate`, `ClientCertificate`, and `ClientKey` field when exporting OTLP over gRPC in `go.opentelemetry.io/contrib/config`. (#6376) (#6378)
 
 ### Changed
 
@@ -38,7 +39,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   - Use `baggagecopy.NewLogProcessor` when configuring a Log Provider.
     - `NewLogProcessor` accepts a `Filter` function type that selects which baggage members are added to the log record.
 
-### Changed 
+### Changed
 
 - Transform raw (`slog.KindAny`) attribute values to matching `log.Value` types.
   For example, `[]string{"foo", "bar"}` attribute value is now transformed to `log.SliceValue(log.StringValue("foo"), log.StringValue("bar"))` instead of `log.String("[foo bar"])`. (#6254)

config/config.go

@@ -5,7 +5,11 @@ package config // import "go.opentelemetry.io/contrib/config"
 
 import (
 	"context"
+	"crypto/tls"
+	"crypto/x509"
 	"errors"
+	"fmt"
+	"os"
 
 	"gopkg.in/yaml.v3"
 
@@ -155,3 +159,30 @@ func toStringMap(pairs []NameStringValuePair) map[string]string {
 	}
 	return output
 }
+
+// createTLSConfig creates a tls.Config from certificate files.
+func createTLSConfig(caCertFile *string, clientCertFile *string, clientKeyFile *string) (*tls.Config, error) {
+	tlsConfig := &tls.Config{}
+	if caCertFile != nil {
+		caText, err := os.ReadFile(*caCertFile)
+		if err != nil {
+			return nil, err
+		}
+		certPool := x509.NewCertPool()
+		if !certPool.AppendCertsFromPEM(caText) {
+			return nil, errors.New("could not create certificate authority chain from certificate")
+		}
+		tlsConfig.RootCAs = certPool
+	}
+	if clientCertFile != nil {
+		if clientKeyFile == nil {
+			return nil, errors.New("client certificate was provided but no client key was provided")
+		}
+		clientCert, err := tls.LoadX509KeyPair(*clientCertFile, *clientKeyFile)
+		if err != nil {
+			return nil, fmt.Errorf("could not use client certificate: %w", err)
+		}
+		tlsConfig.Certificates = []tls.Certificate{clientCert}
+	}
+	return tlsConfig, nil
+}

config/config_test.go

@@ -5,6 +5,7 @@ package config
 
 import (
 	"context"
+	"crypto/tls"
 	"encoding/json"
 	"errors"
 	"os"
@@ -489,6 +490,62 @@ func TestSerializeJSON(t *testing.T) {
 	}
 }
 
+func TestCreateTLSConfig(t *testing.T) {
+	tests := []struct {
+		name           string
+		caCertFile     *string
+		clientCertFile *string
+		clientKeyFile  *string
+		wantErr        error
+		want           func(*tls.Config, *testing.T)
+	}{
+		{
+			name: "no-input",
+			want: func(result *tls.Config, t *testing.T) {
+				require.Nil(t, result.Certificates)
+				require.Nil(t, result.RootCAs)
+			},
+		},
+		{
+			name:       "only-cacert-provided",
+			caCertFile: ptr(filepath.Join("testdata", "ca.crt")),
+			want: func(result *tls.Config, t *testing.T) {
+				require.Nil(t, result.Certificates)
+				require.NotNil(t, result.RootCAs)
+			},
+		},
+		{
+			name:       "nonexistent-cacert-file",
+			caCertFile: ptr("nowhere.crt"),
+			wantErr:    errors.New("open nowhere.crt: no such file or directory"),
+		},
+		{
+			name:           "nonexistent-clientcert-file",
+			clientCertFile: ptr("nowhere.crt"),
+			clientKeyFile:  ptr("nowhere.crt"),
+			wantErr:        errors.New("could not use client certificate: open nowhere.crt: no such file or directory"),
+		},
+		{
+			name:       "bad-cacert-file",
+			caCertFile: ptr(filepath.Join("testdata", "bad_cert.crt")),
+			wantErr:    errors.New("could not create certificate authority chain from certificate"),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := createTLSConfig(tt.caCertFile, tt.clientCertFile, tt.clientKeyFile)
+
+			if tt.wantErr != nil {
+				require.Equal(t, tt.wantErr.Error(), err.Error())
+			} else {
+				require.NoError(t, err)
+				tt.want(got, t)
+			}
+		})
+	}
+}
+
 func ptr[T any](v T) *T {
 	return &v
 }

config/go.mod

@@ -22,6 +22,7 @@ require (
 	go.opentelemetry.io/otel/sdk/log v0.8.0
 	go.opentelemetry.io/otel/sdk/metric v1.32.0
 	go.opentelemetry.io/otel/trace v1.32.0
+	google.golang.org/grpc v1.68.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -47,6 +48,5 @@ require (
 	golang.org/x/text v0.20.0 // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20241118233622-e639e219e697 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20241118233622-e639e219e697 // indirect
-	google.golang.org/grpc v1.68.0 // indirect
 	google.golang.org/protobuf v1.35.2 // indirect
 )

config/log.go

@@ -10,6 +10,8 @@ import (
 	"net/url"
 	"time"
 
+	"google.golang.org/grpc/credentials"
+
 	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
 	"go.opentelemetry.io/otel/exporters/stdout/stdoutlog"
@@ -154,6 +156,12 @@ func otlpHTTPLogExporter(ctx context.Context, otlpConfig *OTLP) (sdklog.Exporter
 		opts = append(opts, otlploghttp.WithHeaders(toStringMap(otlpConfig.Headers)))
 	}
 
+	tlsConfig, err := createTLSConfig(otlpConfig.Certificate, otlpConfig.ClientCertificate, otlpConfig.ClientKey)
+	if err != nil {
+		return nil, err
+	}
+	opts = append(opts, otlploghttp.WithTLSClientConfig(tlsConfig))
+
 	return otlploghttp.New(ctx, opts...)
 }
 
@@ -196,5 +204,11 @@ func otlpGRPCLogExporter(ctx context.Context, otlpConfig *OTLP) (sdklog.Exporter
 		opts = append(opts, otlploggrpc.WithHeaders(toStringMap(otlpConfig.Headers)))
 	}
 
+	tlsConfig, err := createTLSConfig(otlpConfig.Certificate, otlpConfig.ClientCertificate, otlpConfig.ClientKey)
+	if err != nil {
+		return nil, err
+	}
+	opts = append(opts, otlploggrpc.WithTLSCredentials(credentials.NewTLS(tlsConfig)))
+
 	return otlploggrpc.New(ctx, opts...)
 }

config/log_test.go

@@ -6,7 +6,9 @@ package config // import "go.opentelemetry.io/contrib/config"
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net/url"
+	"path/filepath"
 	"reflect"
 	"testing"
 
@@ -221,6 +223,58 @@ func TestLogProcessor(t *testing.T) {
 			},
 			wantProcessor: sdklog.NewBatchProcessor(otlpGRPCExporter),
 		},
+		{
+			name: "batch/otlp-grpc-good-ca-certificate",
+			processor: LogRecordProcessor{
+				Batch: &BatchLogRecordProcessor{
+					Exporter: LogRecordExporter{
+						OTLP: &OTLP{
+							Protocol:    ptr("grpc"),
+							Endpoint:    ptr("localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("testdata", "ca.crt")),
+						},
+					},
+				},
+			},
+			wantProcessor: sdklog.NewBatchProcessor(otlpGRPCExporter),
+		},
+		{
+			name: "batch/otlp-grpc-bad-ca-certificate",
+			processor: LogRecordProcessor{
+				Batch: &BatchLogRecordProcessor{
+					Exporter: LogRecordExporter{
+						OTLP: &OTLP{
+							Protocol:    ptr("grpc"),
+							Endpoint:    ptr("localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("testdata", "bad_cert.crt")),
+						},
+					},
+				},
+			},
+			wantErr: fmt.Errorf("could not create certificate authority chain from certificate"),
+		},
+		{
+			name: "batch/otlp-grpc-bad-client-certificate",
+			processor: LogRecordProcessor{
+				Batch: &BatchLogRecordProcessor{
+					Exporter: LogRecordExporter{
+						OTLP: &OTLP{
+							Protocol:          ptr("grpc"),
+							Endpoint:          ptr("localhost:4317"),
+							Compression:       ptr("gzip"),
+							Timeout:           ptr(1000),
+							ClientCertificate: ptr(filepath.Join("testdata", "bad_cert.crt")),
+							ClientKey:         ptr(filepath.Join("testdata", "bad_cert.crt")),
+						},
+					},
+				},
+			},
+			wantErr: fmt.Errorf("could not use client certificate: %w", errors.New("tls: failed to find any PEM data in certificate input")),
+		},
 		{
 			name: "batch/otlp-grpc-exporter-no-scheme",
 			processor: LogRecordProcessor{
@@ -381,6 +435,58 @@ func TestLogProcessor(t *testing.T) {
 			},
 			wantProcessor: sdklog.NewBatchProcessor(otlpHTTPExporter),
 		},
+		{
+			name: "batch/otlp-http-good-ca-certificate",
+			processor: LogRecordProcessor{
+				Batch: &BatchLogRecordProcessor{
+					Exporter: LogRecordExporter{
+						OTLP: &OTLP{
+							Protocol:    ptr("http/protobuf"),
+							Endpoint:    ptr("localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("testdata", "ca.crt")),
+						},
+					},
+				},
+			},
+			wantProcessor: sdklog.NewBatchProcessor(otlpHTTPExporter),
+		},
+		{
+			name: "batch/otlp-http-bad-ca-certificate",
+			processor: LogRecordProcessor{
+				Batch: &BatchLogRecordProcessor{
+					Exporter: LogRecordExporter{
+						OTLP: &OTLP{
+							Protocol:    ptr("http/protobuf"),
+							Endpoint:    ptr("localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("testdata", "bad_cert.crt")),
+						},
+					},
+				},
+			},
+			wantErr: fmt.Errorf("could not create certificate authority chain from certificate"),
+		},
+		{
+			name: "batch/otlp-http-bad-client-certificate",
+			processor: LogRecordProcessor{
+				Batch: &BatchLogRecordProcessor{
+					Exporter: LogRecordExporter{
+						OTLP: &OTLP{
+							Protocol:          ptr("http/protobuf"),
+							Endpoint:          ptr("localhost:4317"),
+							Compression:       ptr("gzip"),
+							Timeout:           ptr(1000),
+							ClientCertificate: ptr(filepath.Join("testdata", "bad_cert.crt")),
+							ClientKey:         ptr(filepath.Join("testdata", "bad_cert.crt")),
+						},
+					},
+				},
+			},
+			wantErr: fmt.Errorf("could not use client certificate: %w", errors.New("tls: failed to find any PEM data in certificate input")),
+		},
 		{
 			name: "batch/otlp-http-invalid-protocol",
 			processor: LogRecordProcessor{

config/metric.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"google.golang.org/grpc/credentials"
 
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
@@ -181,6 +182,12 @@ func otlpHTTPMetricExporter(ctx context.Context, otlpConfig *OTLPMetric) (sdkmet
 		}
 	}
 
+	tlsConfig, err := createTLSConfig(otlpConfig.Certificate, otlpConfig.ClientCertificate, otlpConfig.ClientKey)
+	if err != nil {
+		return nil, err
+	}
+	opts = append(opts, otlpmetrichttp.WithTLSClientConfig(tlsConfig))
+
 	return otlpmetrichttp.New(ctx, opts...)
 }
 
@@ -236,6 +243,12 @@ func otlpGRPCMetricExporter(ctx context.Context, otlpConfig *OTLPMetric) (sdkmet
 		}
 	}
 
+	tlsConfig, err := createTLSConfig(otlpConfig.Certificate, otlpConfig.ClientCertificate, otlpConfig.ClientKey)
+	if err != nil {
+		return nil, err
+	}
+	opts = append(opts, otlpmetricgrpc.WithTLSCredentials(credentials.NewTLS(tlsConfig)))
+
 	return otlpmetricgrpc.New(ctx, opts...)
 }