/
grpc.go
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/
grpc.go
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// Unless explicitly stated otherwise all files in this repository are licensed
// under the Apache License Version 2.0.
// This product includes software developed at Datadog (https://www.datadoghq.com/).
// Copyright 2016-present Datadog, Inc.
package workloadmeta
import (
"context"
"errors"
"fmt"
"net"
"strconv"
"sync"
"time"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials/insecure"
"google.golang.org/grpc/keepalive"
"github.com/DataDog/datadog-agent/pkg/config"
pbgo "github.com/DataDog/datadog-agent/pkg/proto/pbgo/process"
"github.com/DataDog/datadog-agent/pkg/telemetry"
grpcutil "github.com/DataDog/datadog-agent/pkg/util/grpc"
"github.com/DataDog/datadog-agent/pkg/util/log"
)
// DuplicateConnectionErr is an error that explains the connection was closed because another client tried to connect
//
//nolint:revive // TODO(PROC) Fix revive linter
var DuplicateConnectionErr = errors.New("the stream was closed because another client called StreamEntities")
// GRPCServer implements a gRPC server to expose Process Entities collected with a WorkloadMetaExtractor
type GRPCServer struct {
config config.Reader
extractor *WorkloadMetaExtractor
server *grpc.Server
// The address of the server set by start(). Primarily used for testing. May be nil if start() has not been called.
addr net.Addr
wg sync.WaitGroup
streamMutex *sync.Mutex
closeExistingStream context.CancelFunc
}
const keepaliveInterval = 10 * time.Second
const streamSendTimeout = 1 * time.Minute
var (
invalidVersionError = telemetry.NewSimpleCounter(subsystem, "invalid_version_errors", "The number of times the grpc server receives an entity diff that has an invalid version.")
streamServerError = telemetry.NewSimpleCounter(subsystem, "stream_send_errors", "The number of times the grpc server has failed to send an entity diff to the core agent.")
)
// NewGRPCServer creates a new instance of a GRPCServer
func NewGRPCServer(config config.Reader, extractor *WorkloadMetaExtractor) *GRPCServer {
l := &GRPCServer{
config: config,
extractor: extractor,
server: grpc.NewServer(
grpc.Creds(insecure.NewCredentials()),
grpc.KeepaliveParams(keepalive.ServerParameters{
Time: keepaliveInterval,
}),
),
streamMutex: &sync.Mutex{},
}
pbgo.RegisterProcessEntityStreamServer(l.server, l)
return l
}
func (l *GRPCServer) consumeProcessDiff(diff *ProcessCacheDiff) ([]*pbgo.ProcessEventSet, []*pbgo.ProcessEventUnset) {
setEvents := make([]*pbgo.ProcessEventSet, len(diff.creation))
for i, proc := range diff.creation {
setEvents[i] = processEntityToEventSet(proc)
}
unsetEvents := make([]*pbgo.ProcessEventUnset, len(diff.deletion))
for i, proc := range diff.deletion {
unsetEvents[i] = &pbgo.ProcessEventUnset{Pid: proc.Pid}
}
return setEvents, unsetEvents
}
// Start starts the GRPCServer to listen for new connections
func (l *GRPCServer) Start() error {
log.Info("Starting Process Entity WorkloadMeta gRPC server")
listener, err := getListener(l.config)
if err != nil {
return err
}
l.addr = listener.Addr()
log.Info("Process Entity WorkloadMeta gRPC server has started listening on", listener.Addr().String())
l.wg.Add(1)
go func() {
defer l.wg.Done()
err = l.server.Serve(listener)
if err != nil {
log.Error(err)
}
}()
return nil
}
//nolint:revive // TODO(PROC) Fix revive linter
func (l *GRPCServer) Addr() net.Addr {
return l.addr
}
// Stop stops and cleans up resources allocated by the GRPCServer
func (l *GRPCServer) Stop() {
log.Info("Stopping Process Entity WorkloadMeta gRPC server")
l.server.Stop()
l.wg.Wait()
log.Info("Process Entity WorkloadMeta gRPC server stopped")
}
func sendMsg(stream pbgo.ProcessEntityStream_StreamEntitiesServer, msg *pbgo.ProcessStreamResponse) error {
return grpcutil.DoWithTimeout(func() error {
return stream.Send(msg)
}, streamSendTimeout)
}
// StreamEntities streams Process Entities collected through the WorkloadMetaExtractor
func (l *GRPCServer) StreamEntities(_ *pbgo.ProcessStreamEntitiesRequest, out pbgo.ProcessEntityStream_StreamEntitiesServer) error {
streamCtx := l.acquireStreamCtx()
// When connection is created, send a snapshot of all processes detected on the host so far as "SET" events
procs, snapshotVersion := l.extractor.GetAllProcessEntities()
setEvents := make([]*pbgo.ProcessEventSet, 0, len(procs))
for _, proc := range procs {
setEvents = append(setEvents, processEntityToEventSet(proc))
}
syncMessage := &pbgo.ProcessStreamResponse{
EventID: snapshotVersion,
SetEvents: setEvents,
}
err := sendMsg(out, syncMessage)
if err != nil {
streamServerError.Inc()
log.Warnf("error sending process entity event: %s", err)
return err
}
expectedVersion := snapshotVersion + 1
// Once connection is established, only diffs (process creations/deletions) are sent to the client
for {
select {
case diff := <-l.extractor.ProcessCacheDiff():
// Ensure that if streamCtx.Done() is closed, we always choose that path.
select {
case <-streamCtx.Done():
return DuplicateConnectionErr
default:
}
// Do not send diff if it has the same or older version of the cache snapshot sent on the connection creation
if diff.cacheVersion <= snapshotVersion {
continue
}
// The diff received from the channel should be 1 + the previous version. Otherwise, we have lost data,
// and we should signal the client to resync by closing the stream.
log.Trace("[WorkloadMeta GRPCServer] expected diff version %d, actual %d", expectedVersion, diff.cacheVersion)
if diff.cacheVersion != expectedVersion {
invalidVersionError.Inc()
log.Debug("[WorkloadMeta GRPCServer] missing cache diff - dropping stream")
return fmt.Errorf("missing cache diff: received version = %d; expected = %d", diff.cacheVersion, expectedVersion)
}
expectedVersion++
sets, unsets := l.consumeProcessDiff(diff)
msg := &pbgo.ProcessStreamResponse{
EventID: diff.cacheVersion,
SetEvents: sets,
UnsetEvents: unsets,
}
err := sendMsg(out, msg)
if err != nil {
streamServerError.Inc()
log.Warnf("error sending process entity event: %s", err)
return err
}
case <-out.Context().Done():
err := out.Context().Err()
if err != nil {
log.Warn("The workloadmeta grpc stream was closed:", err)
}
return nil
case <-streamCtx.Done():
return DuplicateConnectionErr
}
}
}
// getListener returns a listening connection
func getListener(cfg config.Reader) (net.Listener, error) {
host, err := config.GetIPCAddress()
if err != nil {
return nil, err
}
address := net.JoinHostPort(host, strconv.Itoa(getGRPCStreamPort(cfg)))
return net.Listen("tcp", address)
}
func getGRPCStreamPort(cfg config.Reader) int {
grpcPort := cfg.GetInt("process_config.language_detection.grpc_port")
if grpcPort <= 0 {
log.Warnf("Invalid process_config.language_detection.grpc_port -- %d, using default port %d", grpcPort, config.DefaultProcessEntityStreamPort)
grpcPort = config.DefaultProcessEntityStreamPort
}
return grpcPort
}
func processEntityToEventSet(proc *ProcessEntity) *pbgo.ProcessEventSet {
var language *pbgo.Language
if proc.Language != nil {
language = &pbgo.Language{Name: string(proc.Language.Name)}
}
return &pbgo.ProcessEventSet{
Pid: proc.Pid,
ContainerID: proc.ContainerId,
Nspid: proc.NsPid,
CreationTime: proc.CreationTime,
Language: language,
}
}
// acquireStreamCtx is responsible for handling locking and cancelling running streams. This ensures that whenever a
// new client connects, the stream is unique.
func (l *GRPCServer) acquireStreamCtx() context.Context {
l.streamMutex.Lock()
defer l.streamMutex.Unlock()
if l.closeExistingStream != nil {
l.closeExistingStream()
}
streamCtx, cancel := context.WithCancel(context.Background())
l.closeExistingStream = cancel
return streamCtx
}