better share lifecycle monitoring and error handling (#463)

agent/agent.go

@@ -14,7 +14,11 @@ type Agent struct {
 	root        env_core.Root
 	agentSocket string
 	shares      map[string]*share
+	inShares    chan *share
+	outShares   chan *share
 	accesses    map[string]*access
+	inAccesses  chan *access
+	outAccesses chan *access
 }
 
 func NewAgent(root env_core.Root) (*Agent, error) {
@@ -24,13 +28,19 @@ func NewAgent(root env_core.Root) (*Agent, error) {
 	return &Agent{
 		root:        root,
 		shares:      make(map[string]*share),
+		inShares:    make(chan *share),
+		outShares:   make(chan *share),
 		accesses:    make(map[string]*access),
+		inAccesses:  make(chan *access),
+		outAccesses: make(chan *access),
 	}, nil
 }
 
 func (a *Agent) Run() error {
 	logrus.Infof("started")
 
+	go a.manager()
+
 	agentSocket, err := a.root.AgentSocket()
 	if err != nil {
 		return err
@@ -55,3 +65,20 @@ func (a *Agent) Shutdown() {
 		logrus.Warnf("unable to remove agent socket: %v", err)
 	}
 }
+
+func (a *Agent) manager() {
+	logrus.Info("started")
+	defer logrus.Warn("exited")
+
+	for {
+		select {
+		case inShare := <-a.inShares:
+			logrus.Infof("adding new share '%v'", inShare.token)
+			a.shares[inShare.token] = inShare
+
+		case outShare := <-a.outShares:
+			logrus.Infof("removing share '%v'", outShare.token)
+			delete(a.shares, outShare.token)
+		}
+	}
+}

agent/model.go

@@ -7,6 +7,7 @@ import (
 	"github.com/openziti/zrok/agent/agentGrpc"
 	"github.com/openziti/zrok/agent/proctree"
 	"github.com/openziti/zrok/sdk/golang/sdk"
+	"github.com/pkg/errors"
 	"strings"
 	"time"
 )
@@ -29,13 +30,25 @@ type share struct {
 
 	process      *proctree.Child
 	readBuffer   bytes.Buffer
-	ready      chan struct{}
+	booted       bool
+	bootComplete chan struct{}
+	bootErr      error
+
+	a *Agent
+}
+
+func (s *share) monitor() {
+	if err := proctree.WaitChild(s.process); err != nil {
+		pfxlog.ChannelLogger(s.token).Error(err)
+	}
+	s.a.outShares <- s
 }
 
 func (s *share) tail(data []byte) {
 	s.readBuffer.Write(data)
 	if line, err := s.readBuffer.ReadString('\n'); err == nil {
-		if s.token == "" {
+		line = strings.Trim(line, "\n")
+		if !s.booted {
 			in := make(map[string]interface{})
 			if err := json.Unmarshal([]byte(line), &in); err == nil {
 				if v, found := in["token"]; found {
@@ -52,8 +65,12 @@ func (s *share) tail(data []byte) {
 						}
 					}
 				}
+				s.booted = true
+			} else {
+				s.bootErr = errors.New(line)
 			}
-			close(s.ready)
+			close(s.bootComplete)
+
 		} else {
 			if strings.HasPrefix(line, "{") {
 				in := make(map[string]interface{})

agent/publicShare.go

@@ -25,7 +25,8 @@ func (i *agentGrpcImpl) PublicShare(_ context.Context, req *agentGrpc.PublicShar
 	shr := &share{
 		shareMode:    sdk.PublicShareMode,
 		backendMode:  sdk.BackendMode(req.BackendMode),
-		ready:       make(chan struct{}),
+		bootComplete: make(chan struct{}),
+		a:            i.a,
 	}
 
 	for _, basicAuth := range req.BasicAuth {
@@ -74,14 +75,18 @@ func (i *agentGrpcImpl) PublicShare(_ context.Context, req *agentGrpc.PublicShar
 
 	shr.process, err = proctree.StartChild(shr.tail, shrCmd...)
 	if err != nil {
-		return nil, err
+		return &agentGrpc.PublicShareReply{}, err
 	}
 
-	<-shr.ready
-	i.a.shares[shr.token] = shr
+	go shr.monitor()
+	<-shr.bootComplete
 
+	if shr.bootErr == nil {
+		i.a.inShares <- shr
 		return &agentGrpc.PublicShareReply{
 			Token:             shr.token,
 			FrontendEndpoints: shr.frontendEndpoints,
 		}, nil
+	}
+	return &agentGrpc.PublicShareReply{}, shr.bootErr
 }