cueball - npm Package Compare versions

Comparing version 2.5.0 to 2.5.1

lib/resolver.js

@@ -386,2 +386,9 @@ /*
 
+	/*
+	 * Set to true if we've ever seen a successful SRV or A/AAAA response
+	 * before. Used for anti-flapping.
+	 */
+	this.r_haveSeenSRV = false;
+	this.r_haveSeenAddr = false;
+
 	FSM.call(this, 'init');
@@ -525,2 +532,3 @@
 		self.r_lastSrvTtl = ttl;
+		self.r_haveSeenSRV = true;
 
@@ -574,3 +582,3 @@ var oldLookup = {};
 				 */
-				self.r_log.trace('nameserver returned NOTIMP ' +
+				self.r_log.info('nameserver returned NOTIMP ' +
 				    'to SRV lookup on %s, will not retry SRV ' +
@@ -590,3 +598,3 @@ 'for 60 min', self.r_service);
 
-			self.r_log.trace('no SRV records found for service ' +
+			self.r_log.info('no SRV records found for service ' +
 			    '%s, trying as a plain name', self.r_service);
@@ -633,7 +641,2 @@
 
-		/*
-		 * Retry in one TTL. Don't proceed to try A/AAAA lookups, to
-		 * avoid flapping back and forth between SRV and A/AAAA mode
-		 * on a service.
-		 */
 		var d = new Date();
@@ -644,2 +647,40 @@ d.setTime(d.getTime() + 1000*self.r_lastSrvTtl);
 		/*
+		 * Anti-flapping measure: we avoid falling back to A/AAAA mode
+		 * unless this is the very first SRV lookup we ever tried and
+		 * it failed after all retries.
+		 *
+		 * We have to keep the fall back on initial SRV failure (even
+		 * though it can cause a nasty flap further into resolver
+		 * operation), because node-moray requires this to work (it
+		 * sets the SRV timeout to 1ms and expects this to result in
+		 * a fall-through to A record operation).
+		 *
+		 * This wasn't meant to be part of the promised API, but it
+		 * is now!
+		 */
+		if (!self.r_haveSeenSRV && !self.r_haveSeenAddr) {
+			self.r_log.debug('no SRV records found for service ' +
+			    '%s, trying as a plain name', self.r_service);
+
+			S.gotoState('aaaa');
+			return;
+
+		} else if (!self.r_haveSeenSRV) {
+			self.r_log.info('no SRV records found for service ' +
+			    '%s, falling back to A/AAAA for 15min',
+			    self.r_service);
+			/*
+			 * We use 15 mins here so that if there's going to be
+			 * a flap back to SRV due to an initial timeout
+			 * (caused by e.g. a network glitch), it will happen in
+			 * the first hour or so of operation.
+			 */
+			d = new Date();
+			d.setTime(d.getTime() + 1000*60*15);
+			self.r_nextService = d;
+			S.gotoState('aaaa');
+			return;
+		}
+
+		/*
 		 * Make sure the next time we wake up is for SRV still, not
@@ -742,2 +783,4 @@ * A or AAAA.
 
+		self.r_haveSeenAddr = true;
+
 		srv.expiry_v6 = d;
@@ -861,2 +904,4 @@ srv.addresses_v6 = ans.map(function (v) {
 
+		self.r_haveSeenAddr = true;
+
 		srv.expiry_v4 = d;
@@ -863,0 +908,0 @@ srv.addresses_v4 = ans.map(function (v) {

package.json

 {
   "name": "cueball",
-  "version": "2.5.0",
+  "version": "2.5.1",
   "description": "manage a pool of connections to a multi-node service where nodes are listed in DNS",
@@ -5,0 +5,0 @@ "main": "lib/index.js",

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Total package byte prevSize

189561

increased by0.87%

Lines of code

5136

increased by0.77%

No dependency changes