add configurable flag for lazy connections to hostParams.go

connect/host.go

@@ -31,7 +31,7 @@ import (
 	"time"
 )
 
-// Information used to describe a connection to a host
+// Host information used to describe a remote connection
 type Host struct {
 	// System-wide ID of the Host
 	id *id.ID
@@ -53,6 +53,9 @@ type Host struct {
 	// GRPC connection object
 	connection      *grpc.ClientConn
 	connectionCount uint64
+	// lock which ensures only a single thread is connecting at a time and
+	// that connections do not interrupt sends
+	connectionMux sync.RWMutex
 
 	// TLS credentials object used to establish the connection
 	credentials credentials.TransportCredentials
@@ -63,10 +66,6 @@ type Host struct {
 	// State tracking for host metric
 	metrics *Metric
 
-	// lock which ensures only a single thread is connecting at a time and
-	// that connections do not interrupt sends
-	connectionMux sync.RWMutex
-
 	coolOffBucket *rateLimiting.Bucket
 	inCoolOff     bool
 
@@ -78,7 +77,7 @@ type Host struct {
 	windowSize *int32
 }
 
-// Creates a new Host object
+// NewHost creates a new Host object
 func NewHost(id *id.ID, address string, cert []byte, params HostParams) (host *Host, err error) {
 
 	windowSize := int32(0)
@@ -108,16 +107,25 @@ func NewHost(id *id.ID, address string, cert []byte, params HostParams) (host *H
 
 	// Configure the host credentials
 	err = host.setCredentials()
+	if err != nil {
 		return
 	}
 
-// the amount of data, when streaming, that a sender can send before receiving an ACK
+	// Connect immediately if configured to do so
+	if !params.LazyConnection {
+		// No mutex required
+		err = host.connect()
+	}
+	return
+}
+
+// SetWindowSize sets the amount of data, when streaming, that a sender can send before receiving an ACK
 // keep at zero to use the default GRPC algorithm to determine
 func (h *Host) SetWindowSize(size int32) {
 	atomic.StoreInt32(h.windowSize, size)
 }
 
-// Simple getter for the public key
+// GetPubKey simple getter for the public key
 func (h *Host) GetPubKey() *rsa.PublicKey {
 	return h.rsaPublicKey
 }
@@ -132,7 +140,7 @@ func (h *Host) Connected() (bool, uint64) {
 }
 
 // connectedUnsafe checks if the given Host's connection is alive without taking
-// a connection lock. Only use if already under a connection lock. The the uint is
+// a connection lock. Only use if already under a connection lock. The uint is
 //the connection count, it increments every time a reconnect occurs
 func (h *Host) connectedUnsafe() (bool, uint64) {
 	return h.isAlive() && !h.authenticationRequired(), h.connectionCount
@@ -143,7 +151,7 @@ func (h *Host) GetMessagingContext() (context.Context, context.CancelFunc) {
 	return h.GetMessagingContextWithTimeout(h.params.SendTimeout)
 }
 
-// GetMessagingContext returns a context object for message sending configured according to HostParams
+// GetMessagingContextWithTimeout returns a context object for message sending configured according to HostParams
 func (h *Host) GetMessagingContextWithTimeout(
 	timeout time.Duration) (context.Context, context.CancelFunc) {
 	return newContext(timeout)
@@ -189,7 +197,7 @@ func (h *Host) isExcludedMetricError(err string) bool {
 	return false
 }
 
-// Sets the host metrics to an arbitrary value. Used for testing
+// SetMetricsTesting sets the host metrics to an arbitrary value. Used for testing
 // purposes only
 func (h *Host) SetMetricsTesting(m *Metric, face interface{}) {
 	// Ensure that this function is only run in testing environments
@@ -204,17 +212,17 @@ func (h *Host) SetMetricsTesting(m *Metric, face interface{}) {
 
 }
 
-// Disconnect closes a the Host connection under the write lock
-// Due to asynchorous connection handling, this may result in
+// Disconnect closes the Host connection under the write lock
+// Due to asynchronous connection handling, this may result in
 // killing a good connection and could result in an immediate
-// reconnection by a seperate thread
+// reconnection by a separate thread
 func (h *Host) Disconnect() {
 	h.connectionMux.Lock()
 	defer h.connectionMux.Unlock()
 	h.disconnect()
 }
 
-// ConditionalDisconnect closes a the Host connection under the write lock only
+// ConditionalDisconnect closes the Host connection under the write lock only
 // if the connection count has not increased
 func (h *Host) conditionalDisconnect(count uint64) {
 	if count == h.connectionCount {
@@ -222,7 +230,7 @@ func (h *Host) conditionalDisconnect(count uint64) {
 	}
 }
 
-// Returns whether or not the Host is able to be contacted
+// IsOnline returns whether the Host is able to be contacted
 // before the timeout by attempting to dial a tcp connection
 // Returns how long the ping took, and whether it was successful
 func (h *Host) IsOnline() (time.Duration, bool) {
@@ -281,7 +289,7 @@ func (h *Host) connect() error {
 }
 
 // authenticationRequired Checks if new authentication is required with
-// the remote.  This is used exclusively under the lock in protocoms.transmit so
+// the remote.  This is used exclusively under the lock in protocomm.transmit so
 // no lock is needed
 func (h *Host) authenticationRequired() bool {
 	return h.params.AuthEnabled && !h.transmissionToken.Has()
@@ -298,10 +306,10 @@ func (h *Host) isAlive() bool {
 		state == connectivity.Ready
 }
 
-// disconnect closes a the Host connection while not under a write lock.
+// disconnect closes the Host connection while not under a write lock.
 // undefined behavior if the caller has not taken the write lock
 func (h *Host) disconnect() {
-	// its possible to close a host which never sent so it never made a
+	// it's possible to close a host which never sent so that it never made a
 	// connection. In that case, we should not close a connection which does not
 	// exist
 	if h.connection != nil {
@@ -442,7 +450,7 @@ func (h *Host) String() string {
 		h.id, addr)
 }
 
-// Stringer interface for connection
+// StringVerbose stringer interface for connection
 func (h *Host) StringVerbose() string {
 	return fmt.Sprintf("%s\t CERTIFICATE: %s", h, h.certificate)
 }

connect/hostParams.go

@@ -41,6 +41,10 @@ type HostParams struct {
 	// If set, metric handling will be enabled on this host
 	EnableMetrics bool
 
+	// If true, a connection will only be established when a comm is sent
+	// else, a connection will be established immediately upon host creation
+	LazyConnection bool
+
 	// List of sending errors that are deemed unimportant
 	// Reception of these errors will not update the Metric state
 	ExcludeMetricErrors []string
@@ -61,6 +65,7 @@ func GetDefaultHostParams() HostParams {
 		SendTimeout:           2 * time.Minute,
 		PingTimeout:           5 * time.Second,
 		EnableMetrics:         false,
+		LazyConnection:        true,
 		ExcludeMetricErrors:   make([]string, 0),
 		KaClientOpts: keepalive.ClientParameters{
 			// Send keepAlive every Time interval

connect/transmit.go

@@ -88,7 +88,7 @@ func (c *ProtoComms) connect(host *Host, count uint64) (uint64, error) {
 	}
 
 	//if the connection is alive return, it is possible for another transmission
-	//to connect between releasing the read lock and taking the write lick
+	//to connect between releasing the read lock and taking the write lock
 	if !host.isAlive() {
 		//connect to host
 		jww.INFO.Printf("Host %s not connected, attempting to connect...",