Add newClient method for otlploggrpc gRPC client (#5523)

part of #5056

For full usage of this client, check #5522

---------

Co-authored-by: Damien Mathieu <[email protected]>
Co-authored-by: Tyler Yahn <[email protected]>

exporters/otlp/otlplog/otlploggrpc/client.go

@@ -3,12 +3,144 @@
 
 package otlploggrpc // import "go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
 
+import (
+	"time"
+
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/backoff"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/encoding/gzip"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc/internal/retry"
+	collogpb "go.opentelemetry.io/proto/otlp/collector/logs/v1"
+)
+
+// The methods of this type are not expected to be called concurrently.
 type client struct {
-	// TODO: implement.
+	metadata      metadata.MD
+	exportTimeout time.Duration
+	requestFunc   retry.RequestFunc
+
+	// ourConn keeps track of where conn was created: true if created here in
+	// NewClient, or false if passed with an option. This is important on
+	// Shutdown as conn should only be closed if we created it. Otherwise,
+	// it is up to the processes that passed conn to close it.
+	ourConn bool
+	conn    *grpc.ClientConn
+	lsc     collogpb.LogsServiceClient
 }
 
+// Used for testing.
+var newGRPCClientFn = grpc.NewClient
+
 // newClient creates a new gRPC log client.
 func newClient(cfg config) (*client, error) {
-	// TODO: implement.
-	return &client{}, nil
+	c := &client{
+		exportTimeout: cfg.timeout.Value,
+		requestFunc:   cfg.retryCfg.Value.RequestFunc(retryable),
+		conn:          cfg.gRPCConn.Value,
+	}
+
+	if len(cfg.headers.Value) > 0 {
+		c.metadata = metadata.New(cfg.headers.Value)
+	}
+
+	if c.conn == nil {
+		// If the caller did not provide a ClientConn when the client was
+		// created, create one using the configuration they did provide.
+		dialOpts := newGRPCDialOptions(cfg)
+
+		conn, err := newGRPCClientFn(cfg.endpoint.Value, dialOpts...)
+		if err != nil {
+			return nil, err
+		}
+		// Keep track that we own the lifecycle of this conn and need to close
+		// it on Shutdown.
+		c.ourConn = true
+		c.conn = conn
+	}
+
+	c.lsc = collogpb.NewLogsServiceClient(c.conn)
+
+	return c, nil
+}
+
+func newGRPCDialOptions(cfg config) []grpc.DialOption {
+	userAgent := "OTel Go OTLP over gRPC logs exporter/" + Version()
+	dialOpts := []grpc.DialOption{grpc.WithUserAgent(userAgent)}
+	dialOpts = append(dialOpts, cfg.dialOptions.Value...)
+
+	// Convert other grpc configs to the dial options.
+	// Service config
+	if cfg.serviceConfig.Value != "" {
+		dialOpts = append(dialOpts, grpc.WithDefaultServiceConfig(cfg.serviceConfig.Value))
+	}
+	// Prioritize GRPCCredentials over Insecure (passing both is an error).
+	if cfg.gRPCCredentials.Value != nil {
+		dialOpts = append(dialOpts, grpc.WithTransportCredentials(cfg.gRPCCredentials.Value))
+	} else if cfg.insecure.Value {
+		dialOpts = append(dialOpts, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	} else {
+		// Default to using the host's root CA.
+		dialOpts = append(dialOpts, grpc.WithTransportCredentials(
+			credentials.NewTLS(nil),
+		))
+	}
+	// Compression
+	if cfg.compression.Value == GzipCompression {
+		dialOpts = append(dialOpts, grpc.WithDefaultCallOptions(grpc.UseCompressor(gzip.Name)))
+	}
+	// Reconnection period
+	if cfg.reconnectionPeriod.Value != 0 {
+		p := grpc.ConnectParams{
+			Backoff:           backoff.DefaultConfig,
+			MinConnectTimeout: cfg.reconnectionPeriod.Value,
+		}
+		dialOpts = append(dialOpts, grpc.WithConnectParams(p))
+	}
+
+	return dialOpts
+}
+
+// retryable returns if err identifies a request that can be retried and a
+// duration to wait for if an explicit throttle time is included in err.
+func retryable(err error) (bool, time.Duration) {
+	s := status.Convert(err)
+	return retryableGRPCStatus(s)
+}
+
+func retryableGRPCStatus(s *status.Status) (bool, time.Duration) {
+	switch s.Code() {
+	case codes.Canceled,
+		codes.DeadlineExceeded,
+		codes.Aborted,
+		codes.OutOfRange,
+		codes.Unavailable,
+		codes.DataLoss:
+		// Additionally, handle RetryInfo.
+		_, d := throttleDelay(s)
+		return true, d
+	case codes.ResourceExhausted:
+		// Retry only if the server signals that the recovery from resource exhaustion is possible.
+		return throttleDelay(s)
+	}
+
+	// Not a retry-able error.
+	return false, 0
+}
+
+// throttleDelay returns if the status is RetryInfo
+// and the duration to wait for if an explicit throttle time is included.
+func throttleDelay(s *status.Status) (bool, time.Duration) {
+	for _, detail := range s.Details() {
+		if t, ok := detail.(*errdetails.RetryInfo); ok {
+			return true, t.RetryDelay.AsDuration()
+		}
+	}
+	return false, 0
 }

exporters/otlp/otlplog/otlploggrpc/client_test.go

@@ -0,0 +1,227 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package otlploggrpc // import "go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/durationpb"
+
+	collogpb "go.opentelemetry.io/proto/otlp/collector/logs/v1"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestThrottleDelay(t *testing.T) {
+	c := codes.ResourceExhausted
+	testcases := []struct {
+		status       *status.Status
+		wantOK       bool
+		wantDuration time.Duration
+	}{
+		{
+			status:       status.New(c, "NoRetryInfo"),
+			wantOK:       false,
+			wantDuration: 0,
+		},
+		{
+			status: func() *status.Status {
+				s, err := status.New(c, "SingleRetryInfo").WithDetails(
+					&errdetails.RetryInfo{
+						RetryDelay: durationpb.New(15 * time.Millisecond),
+					},
+				)
+				require.NoError(t, err)
+				return s
+			}(),
+			wantOK:       true,
+			wantDuration: 15 * time.Millisecond,
+		},
+		{
+			status: func() *status.Status {
+				s, err := status.New(c, "ErrorInfo").WithDetails(
+					&errdetails.ErrorInfo{Reason: "no throttle detail"},
+				)
+				require.NoError(t, err)
+				return s
+			}(),
+			wantOK:       false,
+			wantDuration: 0,
+		},
+		{
+			status: func() *status.Status {
+				s, err := status.New(c, "ErrorAndRetryInfo").WithDetails(
+					&errdetails.ErrorInfo{Reason: "with throttle detail"},
+					&errdetails.RetryInfo{
+						RetryDelay: durationpb.New(13 * time.Minute),
+					},
+				)
+				require.NoError(t, err)
+				return s
+			}(),
+			wantOK:       true,
+			wantDuration: 13 * time.Minute,
+		},
+		{
+			status: func() *status.Status {
+				s, err := status.New(c, "DoubleRetryInfo").WithDetails(
+					&errdetails.RetryInfo{
+						RetryDelay: durationpb.New(13 * time.Minute),
+					},
+					&errdetails.RetryInfo{
+						RetryDelay: durationpb.New(15 * time.Minute),
+					},
+				)
+				require.NoError(t, err)
+				return s
+			}(),
+			wantOK:       true,
+			wantDuration: 13 * time.Minute,
+		},
+	}
+
+	for _, tc := range testcases {
+		t.Run(tc.status.Message(), func(t *testing.T) {
+			ok, d := throttleDelay(tc.status)
+			assert.Equal(t, tc.wantOK, ok)
+			assert.Equal(t, tc.wantDuration, d)
+		})
+	}
+}
+
+func TestRetryable(t *testing.T) {
+	retryableCodes := map[codes.Code]bool{
+		codes.OK:                 false,
+		codes.Canceled:           true,
+		codes.Unknown:            false,
+		codes.InvalidArgument:    false,
+		codes.DeadlineExceeded:   true,
+		codes.NotFound:           false,
+		codes.AlreadyExists:      false,
+		codes.PermissionDenied:   false,
+		codes.ResourceExhausted:  false,
+		codes.FailedPrecondition: false,
+		codes.Aborted:            true,
+		codes.OutOfRange:         true,
+		codes.Unimplemented:      false,
+		codes.Internal:           false,
+		codes.Unavailable:        true,
+		codes.DataLoss:           true,
+		codes.Unauthenticated:    false,
+	}
+
+	for c, want := range retryableCodes {
+		got, _ := retryable(status.Error(c, ""))
+		assert.Equalf(t, want, got, "evaluate(%s)", c)
+	}
+}
+
+func TestRetryableGRPCStatusResourceExhaustedWithRetryInfo(t *testing.T) {
+	delay := 15 * time.Millisecond
+	s, err := status.New(codes.ResourceExhausted, "WithRetryInfo").WithDetails(
+		&errdetails.RetryInfo{
+			RetryDelay: durationpb.New(delay),
+		},
+	)
+	require.NoError(t, err)
+
+	ok, d := retryableGRPCStatus(s)
+	assert.True(t, ok)
+	assert.Equal(t, delay, d)
+}
+
+func TestNewClient(t *testing.T) {
+	newGRPCClientFnSwap := newGRPCClientFn
+	t.Cleanup(func() {
+		newGRPCClientFn = newGRPCClientFnSwap
+	})
+
+	// The gRPC connection created by newClient.
+	conn, err := grpc.NewClient("test", grpc.WithTransportCredentials(insecure.NewCredentials()))
+	require.NoError(t, err)
+	newGRPCClientFn = func(target string, opts ...grpc.DialOption) (*grpc.ClientConn, error) {
+		return conn, nil
+	}
+
+	// The gRPC connection created by users.
+	userConn, err := grpc.NewClient("test 2", grpc.WithTransportCredentials(insecure.NewCredentials()))
+	require.NoError(t, err)
+
+	testCases := []struct {
+		name string
+		cfg  config
+		cli  *client
+	}{
+		{
+			name: "empty config",
+			cli: &client{
+				ourConn: true,
+				conn:    conn,
+				lsc:     collogpb.NewLogsServiceClient(conn),
+			},
+		},
+		{
+			name: "with headers",
+			cfg: config{
+				headers: newSetting(map[string]string{
+					"key": "value",
+				}),
+			},
+			cli: &client{
+				ourConn:  true,
+				conn:     conn,
+				lsc:      collogpb.NewLogsServiceClient(conn),
+				metadata: map[string][]string{"key": {"value"}},
+			},
+		},
+		{
+			name: "with gRPC connection",
+			cfg: config{
+				gRPCConn: newSetting(userConn),
+			},
+			cli: &client{
+				ourConn: false,
+				conn:    userConn,
+				lsc:     collogpb.NewLogsServiceClient(userConn),
+			},
+		},
+		{
+			// It is not possible to compare grpc dial options directly, so we just check that the client is created
+			// and no panic occurs.
+			name: "with dial options",
+			cfg: config{
+				serviceConfig:      newSetting("service config"),
+				gRPCCredentials:    newSetting(credentials.NewTLS(nil)),
+				compression:        newSetting(GzipCompression),
+				reconnectionPeriod: newSetting(10 * time.Second),
+			},
+			cli: &client{
+				ourConn: true,
+				conn:    conn,
+				lsc:     collogpb.NewLogsServiceClient(conn),
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			cli, err := newClient(tc.cfg)
+			require.NoError(t, err)
+
+			assert.Equal(t, tc.cli.metadata, cli.metadata)
+			assert.Equal(t, tc.cli.exportTimeout, cli.exportTimeout)
+			assert.Equal(t, tc.cli.ourConn, cli.ourConn)
+			assert.Equal(t, tc.cli.conn, cli.conn)
+			assert.Equal(t, tc.cli.lsc, cli.lsc)
+		})
+	}
+}