Allow SendMessageToGroups to silently retry prior to failing

protocol/connections/engine.go

@@ -160,7 +160,7 @@ func (e *engine) eventHandler() {
 		case event.SendMessageToGroup:
 			ciphertext, _ := base64.StdEncoding.DecodeString(ev.Data[event.Ciphertext])
 			signature, _ := base64.StdEncoding.DecodeString(ev.Data[event.Signature])
-			go e.sendMessageToGroup(ev.Data[event.GroupID], ev.Data[event.GroupServer], ciphertext, signature)
+			go e.sendMessageToGroup(ev.Data[event.GroupID], ev.Data[event.GroupServer], ciphertext, signature, 0)
 		case event.SendMessageToPeer:
 			// TODO: remove this passthrough once the UI is integrated.
 			context, ok := ev.Data[event.EventContext]
@@ -480,7 +480,17 @@ func (e *engine) receiveGroupMessage(server string, gm *groups.EncryptedGroupMes
 }
 
 // sendMessageToGroup attempts to sent the given message to the given group id.
-func (e *engine) sendMessageToGroup(groupID string, server string, ct []byte, sig []byte) {
+func (e *engine) sendMessageToGroup(groupID string, server string, ct []byte, sig []byte, attempts int) {
+
+	// sending to groups can fail for a few reasons (slow server, not enough tokens, etc.)
+	// rather than trying to keep all that logic in method we simply back-off and try again
+	// but if we fail more than 5 times then we report back to the client so they can investigate other options.
+	// Note: This flow only applies to online-and-connected servers (this method will return faster if the server is not
+	// online)
+	if attempts >= 5 {
+		e.eventManager.Publish(event.NewEvent(event.SendMessageToGroupError, map[event.Field]string{event.GroupID: groupID, event.GroupServer: server, event.Error: "could not make payment to server", event.Signature: base64.StdEncoding.EncodeToString(sig)}))
+		return
+	}
 
 	es, ok := e.ephemeralServices.Load(server)
 	if es == nil || !ok {
@@ -493,17 +503,16 @@ func (e *engine) sendMessageToGroup(groupID string, server string, ct []byte, si
 	if err == nil {
 		tokenApp, ok := (conn.App()).(*TokenBoardClient)
 		if ok {
-			if spent, _ := tokenApp.Post(ct, sig); !spent {
-				// TODO: while this works for the spam guard, it won't work for other forms of payment...
-				// Make an -inline- payment, this will hold the goroutine
-				if err := tokenApp.MakePayment(); err == nil {
-					// This really shouldn't fail since we now know we have the required tokens...
-					if spent, numTokens := tokenApp.Post(ct, sig); !spent {
-						e.eventManager.Publish(event.NewEvent(event.SendMessageToGroupError, map[event.Field]string{event.GroupID: groupID, event.GroupServer: server, event.Error: fmt.Errorf("could not post %v", numTokens).Error(), event.Signature: base64.StdEncoding.EncodeToString(sig)}))
-					}
-				} else {
-					// Broadcast the token error
-					e.eventManager.Publish(event.NewEvent(event.SendMessageToGroupError, map[event.Field]string{event.GroupID: groupID, event.GroupServer: server, event.Error: err.Error(), event.Signature: base64.StdEncoding.EncodeToString(sig)}))
+			if spent, numtokens := tokenApp.Post(ct, sig); !spent {
+				// we failed to post, probably because we ran out of tokens... so make a payment
+				go tokenApp.MakePayment()
+				// backoff
+				time.Sleep(time.Second)
+				// try again
+				e.sendMessageToGroup(groupID, server, ct, sig, attempts+1)
+			} else {
+				if numtokens < 5 {
+					go tokenApp.MakePayment()
 				}
 			}
 			// regardless we return....

protocol/connections/tokenboardclientapp.go

@@ -13,6 +13,7 @@ import (
 	"git.openprivacy.ca/openprivacy/log"
 	"github.com/gtank/ristretto255"
 	"sync"
+	"time"
 )
 
 // NewTokenBoardClient generates a new Client for Token Board
@@ -190,24 +191,28 @@ func (ta *TokenBoardClient) MakePayment() error {
 		conn, _ = client.GetConnection(ta.tokenServiceOnion)
 	}
 
-	client.Connect(ta.tokenServiceOnion, powTokenApp)
-	conn, err := client.WaitForCapabilityOrClose(ta.tokenServiceOnion, applications.HasTokensCapability)
-	if err == nil {
-		powtapp, ok := conn.App().(*applications.TokenApplication)
-		if ok {
-			// Update tokens...we need a lock here to prevent SpendToken from modifying the tokens
-			// during this process..
-			log.Debugf("Updating Tokens")
-			ta.tokenLock.Lock()
-			ta.tokens = append(ta.tokens, powtapp.Tokens...)
-			if len(ta.tokens) < 10 {
-				go ta.MakePayment()
+	connected, err := client.Connect(ta.tokenServiceOnion, powTokenApp)
+	if connected == true && err == nil {
+		conn, err := client.WaitForCapabilityOrClose(ta.tokenServiceOnion, applications.HasTokensCapability)
+		if err == nil {
+			powtapp, ok := conn.App().(*applications.TokenApplication)
+			if ok {
+				// Update tokens...we need a lock here to prevent SpendToken from modifying the tokens
+				// during this process..
+				log.Debugf("Updating Tokens")
+				ta.tokenLock.Lock()
+				ta.tokens = append(ta.tokens, powtapp.Tokens...)
+				ta.tokenLock.Unlock()
+				log.Debugf("Transcript: %v", powtapp.Transcript().OutputTranscriptToAudit())
+				conn.Close()
+				return nil
 			}
-			ta.tokenLock.Unlock()
-			log.Debugf("Transcript: %v", powtapp.Transcript().OutputTranscriptToAudit())
-			conn.Close()
-			return nil
 		}
+	} else {
+		log.Debugf("failed to make a connection. trying again...")
+		// it doesn't actually take that long to make a payment, so waiting a small amount of time should suffice
+		time.Sleep(time.Second)
+		return ta.MakePayment()
 	}
 	log.Debugf("Error making payment: to %v %v", ta.tokenServiceOnion, err)
 	return err