Add reconnect on errors in read loop

Signed-off-by: Piotr Piotrowski <piotr@synadia.com>

Author: piotrpio

Sources/NatsSwift/Extensions/Data+Parser.swift

@@ -67,7 +67,7 @@ extension Data {
         self = other + self
     }
 
-    internal func parseOutMessages() -> (ops: [ServerOp], remainder: Data?) {
+    internal func parseOutMessages() throws -> (ops: [ServerOp], remainder: Data?) {
         var serverOps = [ServerOp]()
         var startIndex = self.startIndex
         var remainder: Data?
@@ -88,15 +88,7 @@ extension Data {
                 continue
             }
 
-            let serverOp: ServerOp
-            do {
-                serverOp = try ServerOp.parse(from: lineData)
-            } catch {
-                // TODO(pp): handle this error properly (maybe surface in throw)
-                logger.error("Error parsing message: \(error)")
-                startIndex = nextLineStartIndex
-                continue
-            }
+            let serverOp = try ServerOp.parse(from: lineData)
 
             // if it's a message, get the full payload and add to returned data
             if case .Message(var msg) = serverOp {

Sources/NatsSwift/Extensions/String+Utilities.swift

@@ -6,11 +6,16 @@
 import Foundation
 
 extension String {
+    private static let charactersToTrim: CharacterSet = .whitespacesAndNewlines.union(CharacterSet(charactersIn: "'"))
 
     static func hash() -> String {
         let uuid = String.uuid()
         return uuid[0...7]
     }
+    
+    func trimWhitespacesAndApostrophes() -> String {
+        return self.trimmingCharacters(in: String.charactersToTrim)
+    }
 
     static func uuid() -> String {
         return UUID().uuidString.trimmingCharacters(in: .punctuationCharacters)

Sources/NatsSwift/NatsConnection.swift

@@ -49,7 +49,15 @@ class ConnectionHandler: ChannelInboundHandler {
         }
 
         self.parseRemainder = nil
-        let parseResult = inputChunk.parseOutMessages()
+        let parseResult: (ops: [ServerOp], remainder: Data?)
+        do {
+            parseResult = try inputChunk.parseOutMessages()
+        } catch {
+            // if parsing throws an error, return and reconnect
+            inputBuffer.clear()
+            context.fireErrorCaught(error)
+            return
+        }
         if let remainder = parseResult.remainder {
             self.parseRemainder = remainder
         }
@@ -96,6 +104,14 @@ class ConnectionHandler: ChannelInboundHandler {
                 self.outstandingPings.store(0, ordering: AtomicStoreOrdering.relaxed)
             case let .Error(err):
                 logger.debug("error \(err)")
+                
+                let normalizedError = err.normalizedError
+                // on some errors, force reconnect
+                if normalizedError == "stale connection" || normalizedError == "maximum connections exceeded" {
+                    inputBuffer.clear()
+                    context.fireErrorCaught(err)
+                }
+                // TODO(pp): handle auth errors here
             case let .Message(msg):
                 self.handleIncomingMessage(msg)
             case let .HMessage(msg):

Sources/NatsSwift/NatsError.swift

@@ -10,6 +10,9 @@ protocol NatsError: Error {
 
 struct NatsConnectionError: NatsError {
     var description: String
+    var normalizedError: String {
+        return description.trimWhitespacesAndApostrophes().lowercased()
+    }
     init(_ description: String) {
         self.description = description
     }

Sources/NatsSwift/NatsProto.swift

@@ -34,10 +34,10 @@ enum ServerOp {
     case Info(ServerInfo)
     case Ping
     case Pong
-    case Error(NatsError)
+    case Error(NatsConnectionError)
     case Message(MessageInbound)
     case HMessage(HMessageInbound)
-
+    
     static func parse(from message: Data) throws -> ServerOp {
         guard message.count > 2 else {
             throw NSError(domain: "nats_swift", code: 1, userInfo: ["message": "unable to parse inbound message: \(message)"])
@@ -53,7 +53,7 @@ enum ServerOp {
         case .ok:
             return Ok
         case .error:
-            if let errMsg = message.toString() {
+            if let errMsg = message.removePrefix(Data(NatsOperation.error.rawBytes)).toString() {
                 return Error(NatsConnectionError(errMsg))
             }
             return Error(NatsConnectionError("unexpected error"))

Tests/NatsSwiftTests/Unit/ParserTests.swift

@@ -96,7 +96,7 @@ class ParserTests: XCTestCase {
                 if let prevRemainder {
                     chunkData.prepend(prevRemainder)
                 }
-                let res = chunkData.parseOutMessages()
+                let res = try! chunkData.parseOutMessages()
                 prevRemainder = res.remainder
                 ops.append(contentsOf: res.ops)
             }