config: add support for certificate configuration (#6376)

Part of
#6351

---------

Signed-off-by: Alex Boten <223565+codeboten@users.noreply.github.com>

.golangci.yml

@@ -70,6 +70,12 @@ issues:
         - gosec
         - perfsprint
         - usestdlibvars
+    # Ignoring gosec G402: TLS MinVersion too low
+    # as the https://pkg.go.dev/crypto/tls#Config handles MinVersion default well.
+    - path: config/*.go
+      text: "G402: TLS MinVersion too low."
+      linters:
+        - gosec
   include:
     # revive exported should have comment or be unexported.
     - EXC0012

CHANGELOG.md

@@ -16,6 +16,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   This module provides an OpenTelemetry logging bridge for `github.com/go-logr/logr`. (#6386)
 - Added SNS instrumentation in `go.opentelemetry.io/contrib/instrumentation/github.com/aws/aws-sdk-go-v2/otelaws`. (#6388)
 - Use a `sync.Pool` for metric options in `go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp`. (#6394)
+- Added support for configuring `Certificate` field when configuring OTLP exporters in `go.opentelemetry.io/contrib/config`. (#6376)
 
 ### Changed
 

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 v1.68.1
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -47,6 +48,5 @@ require (
 	golang.org/x/text v0.21.0 // indirect
 	google.golang.org/genproto/googleapis/api v0.0.0-20241209162323-e6fa225c2576 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20241209162323-e6fa225c2576 // indirect
-	google.golang.org/grpc v1.68.1 // indirect
 	google.golang.org/protobuf v1.35.2 // indirect
 )

config/testdata/bad_cert.crt

@@ -0,0 +1 @@
+This is intentionally not a PEM formatted cert file.

config/testdata/ca.crt

@@ -0,0 +1,20 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

config/v0.3.0/config.go

@@ -5,7 +5,10 @@ package config // import "go.opentelemetry.io/contrib/config/v0.3.0"
 
 import (
 	"context"
+	"crypto/tls"
+	"crypto/x509"
 	"errors"
+	"os"
 
 	"gopkg.in/yaml.v3"
 
@@ -155,3 +158,20 @@ func toStringMap(pairs []NameStringValuePair) map[string]string {
 	}
 	return output
 }
+
+// createTLSConfig creates a tls.Config from a raw certificate bytes
+// to verify a server certificate.
+func createTLSConfig(certFile string) (*tls.Config, error) {
+	b, err := os.ReadFile(certFile)
+	if err != nil {
+		return nil, err
+	}
+	cp := x509.NewCertPool()
+	if ok := cp.AppendCertsFromPEM(b); !ok {
+		return nil, errors.New("failed to append certificate to the cert pool")
+	}
+
+	return &tls.Config{
+		RootCAs: cp,
+	}, nil
+}

config/v0.3.0/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 +156,14 @@ func otlpHTTPLogExporter(ctx context.Context, otlpConfig *OTLP) (sdklog.Exporter
 		opts = append(opts, otlploghttp.WithHeaders(toStringMap(otlpConfig.Headers)))
 	}
 
+	if otlpConfig.Certificate != nil {
+		creds, err := createTLSConfig(*otlpConfig.Certificate)
+		if err != nil {
+			return nil, fmt.Errorf("could not create client tls credentials: %w", err)
+		}
+		opts = append(opts, otlploghttp.WithTLSClientConfig(creds))
+	}
+
 	return otlploghttp.New(ctx, opts...)
 }
 
@@ -196,5 +206,13 @@ func otlpGRPCLogExporter(ctx context.Context, otlpConfig *OTLP) (sdklog.Exporter
 		opts = append(opts, otlploggrpc.WithHeaders(toStringMap(otlpConfig.Headers)))
 	}
 
+	if otlpConfig.Certificate != nil {
+		creds, err := credentials.NewClientTLSFromFile(*otlpConfig.Certificate, "")
+		if err != nil {
+			return nil, fmt.Errorf("could not create client tls credentials: %w", err)
+		}
+		opts = append(opts, otlploggrpc.WithTLSCredentials(creds))
+	}
+
 	return otlploggrpc.New(ctx, opts...)
 }

config/v0.3.0/log_test.go

@@ -6,7 +6,9 @@ package config
 import (
 	"context"
 	"errors"
+	"fmt"
 	"net/url"
+	"path/filepath"
 	"reflect"
 	"testing"
 
@@ -221,6 +223,40 @@ 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 client tls credentials: %w", errors.New("credentials: failed to append certificates")),
+		},
 		{
 			name: "batch/otlp-grpc-exporter-no-scheme",
 			processor: LogRecordProcessor{
@@ -313,6 +349,40 @@ 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 client tls credentials: %w", errors.New("failed to append certificate to the cert pool")),
+		},
 		{
 			name: "batch/otlp-http-exporter-with-path",
 			processor: LogRecordProcessor{

config/v0.3.0/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 +182,14 @@ func otlpHTTPMetricExporter(ctx context.Context, otlpConfig *OTLPMetric) (sdkmet
 		}
 	}
 
+	if otlpConfig.Certificate != nil {
+		creds, err := createTLSConfig(*otlpConfig.Certificate)
+		if err != nil {
+			return nil, fmt.Errorf("could not create client tls credentials: %w", err)
+		}
+		opts = append(opts, otlpmetrichttp.WithTLSClientConfig(creds))
+	}
+
 	return otlpmetrichttp.New(ctx, opts...)
 }
 
@@ -236,6 +245,14 @@ func otlpGRPCMetricExporter(ctx context.Context, otlpConfig *OTLPMetric) (sdkmet
 		}
 	}
 
+	if otlpConfig.Certificate != nil {
+		creds, err := credentials.NewClientTLSFromFile(*otlpConfig.Certificate, "")
+		if err != nil {
+			return nil, fmt.Errorf("could not create client tls credentials: %w", err)
+		}
+		opts = append(opts, otlpmetricgrpc.WithTLSCredentials(creds))
+	}
+
 	return otlpmetricgrpc.New(ctx, opts...)
 }
 

config/v0.3.0/metric_test.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"net/url"
+	"path/filepath"
 	"reflect"
 	"testing"
 	"time"
@@ -215,6 +216,40 @@ func TestReader(t *testing.T) {
 			},
 			wantReader: sdkmetric.NewPeriodicReader(otlpGRPCExporter),
 		},
+		{
+			name: "periodic/otlp-grpc-good-ca-certificate",
+			reader: MetricReader{
+				Periodic: &PeriodicMetricReader{
+					Exporter: PushMetricExporter{
+						OTLP: &OTLPMetric{
+							Protocol:    ptr("grpc"),
+							Endpoint:    ptr("https://localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("..", "testdata", "ca.crt")),
+						},
+					},
+				},
+			},
+			wantReader: sdkmetric.NewPeriodicReader(otlpGRPCExporter),
+		},
+		{
+			name: "periodic/otlp-grpc-bad-ca-certificate",
+			reader: MetricReader{
+				Periodic: &PeriodicMetricReader{
+					Exporter: PushMetricExporter{
+						OTLP: &OTLPMetric{
+							Protocol:    ptr("grpc"),
+							Endpoint:    ptr("https://localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("..", "testdata", "bad_cert.crt")),
+						},
+					},
+				},
+			},
+			wantErr: fmt.Errorf("could not create client tls credentials: %w", errors.New("credentials: failed to append certificates")),
+		},
 		{
 			name: "periodic/otlp-grpc-exporter-no-endpoint",
 			reader: MetricReader{
@@ -408,6 +443,40 @@ func TestReader(t *testing.T) {
 			},
 			wantReader: sdkmetric.NewPeriodicReader(otlpHTTPExporter),
 		},
+		{
+			name: "periodic/otlp-http-good-ca-certificate",
+			reader: MetricReader{
+				Periodic: &PeriodicMetricReader{
+					Exporter: PushMetricExporter{
+						OTLP: &OTLPMetric{
+							Protocol:    ptr("http/protobuf"),
+							Endpoint:    ptr("https://localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("..", "testdata", "ca.crt")),
+						},
+					},
+				},
+			},
+			wantReader: sdkmetric.NewPeriodicReader(otlpHTTPExporter),
+		},
+		{
+			name: "periodic/otlp-http-bad-ca-certificate",
+			reader: MetricReader{
+				Periodic: &PeriodicMetricReader{
+					Exporter: PushMetricExporter{
+						OTLP: &OTLPMetric{
+							Protocol:    ptr("http/protobuf"),
+							Endpoint:    ptr("https://localhost:4317"),
+							Compression: ptr("gzip"),
+							Timeout:     ptr(1000),
+							Certificate: ptr(filepath.Join("..", "testdata", "bad_cert.crt")),
+						},
+					},
+				},
+			},
+			wantErr: fmt.Errorf("could not create client tls credentials: %w", errors.New("failed to append certificate to the cert pool")),
+		},
 		{
 			name: "periodic/otlp-http-exporter-with-path",
 			reader: MetricReader{

config/v0.3.0/trace.go

@@ -10,6 +10,8 @@ import (
 	"net/url"
 	"time"
 
+	"google.golang.org/grpc/credentials"
+
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
 	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
 	"go.opentelemetry.io/otel/exporters/stdout/stdouttrace"
@@ -127,6 +129,14 @@ func otlpGRPCSpanExporter(ctx context.Context, otlpConfig *OTLP) (sdktrace.SpanE
 		opts = append(opts, otlptracegrpc.WithHeaders(toStringMap(otlpConfig.Headers)))
 	}
 
+	if otlpConfig.Certificate != nil {
+		creds, err := credentials.NewClientTLSFromFile(*otlpConfig.Certificate, "")
+		if err != nil {
+			return nil, fmt.Errorf("could not create client tls credentials: %w", err)
+		}
+		opts = append(opts, otlptracegrpc.WithTLSCredentials(creds))
+	}
+
 	return otlptracegrpc.New(ctx, opts...)
 }
 
@@ -164,6 +174,14 @@ func otlpHTTPSpanExporter(ctx context.Context, otlpConfig *OTLP) (sdktrace.SpanE
 		opts = append(opts, otlptracehttp.WithHeaders(toStringMap(otlpConfig.Headers)))
 	}
 
+	if otlpConfig.Certificate != nil {
+		creds, err := createTLSConfig(*otlpConfig.Certificate)
+		if err != nil {
+			return nil, fmt.Errorf("could not create client tls credentials: %w", err)
+		}
+		opts = append(opts, otlptracehttp.WithTLSClientConfig(creds))
+	}
+
 	return otlptracehttp.New(ctx, opts...)
 }