Error handling for connecting to a non-routing server

Author: pontusmelke

src/v1/driver.js

@@ -22,7 +22,7 @@ import Pool from './internal/pool';
 import Integer from './integer';
 import {connect} from "./internal/connector";
 import StreamObserver from './internal/stream-observer';
-import {newError} from "./error";
+import {newError, SERVICE_UNAVAILABLE} from "./error";
 import "babel-polyfill";
 
 let READ = 'READ', WRITE = 'WRITE';
@@ -113,6 +113,13 @@ class Driver {
    */
   session(mode) {
     let connectionPromise = this._acquireConnection(mode);
+    connectionPromise.catch((err) => {
+      if (this.onError && err.code === SERVICE_UNAVAILABLE) {
+        this.onError(err);
+      } else {
+        return Promise.reject(err);
+      }
+    });
     return this._createSession(connectionPromise, (cb) => {
       // This gets called on Session#close(), and is where we return
       // the pooled 'connection' instance.

src/v1/routing-driver.js

@@ -38,13 +38,24 @@ class RoutingDriver extends Driver {
   _createSession(connectionPromise, cb) {
     return new RoutingSession(connectionPromise, cb, (err, conn) => {
       let code = err.code;
+      let msg = err.message;
       if (!code) {
         try {
           code = err.fields[0].code;
         } catch (e) {
           code = 'UNKNOWN';
         }
       }
+      if (!msg) {
+        try {
+          msg = err.fields[0].message;
+        } catch (e) {
+          msg = 'Unknown failure occurred';
+        }
+      }
+      //just to simplify later error handling
+      err.code = code;
+      err.message = msg;
 
       if (code === SERVICE_UNAVAILABLE || code === SESSION_EXPIRED) {
         if (conn) {
@@ -65,8 +76,9 @@ class RoutingDriver extends Driver {
             this._clusterView.writers.remove(conn.url);
           });
         }
-
         return newError("No longer possible to write to server at " + url, SESSION_EXPIRED);
+      } else {
+        return err;
       }
     });
   }
@@ -224,8 +236,12 @@ function newClusterView(session) {
       }
       return new ClusterView(routers, readers, writers, expires);
     })
-    .catch(() => {
+    .catch((e) => {
+      if (e.code === 'Neo.ClientError.Procedure.ProcedureNotFound') {
+        return Promise.reject(newError("Server could not perform routing, make sure you are connecting to a causal cluster", SERVICE_UNAVAILABLE));
+      } else {
       return Promise.reject(newError("No servers could be found at this instant.", SERVICE_UNAVAILABLE));
+      }
     });
 }
 

test/v1/driver.test.js

@@ -111,7 +111,22 @@ describe('driver', function() {
     var driver = neo4j.driver("bolt://localhost", neo4j.auth.custom("neo4j", "neo4j", "native", "basic", {secret: 42}));
 
     // Expect
-    driver.onCompleted = function (meta) {
+    driver.onCompleted = function () {
+      done();
+    };
+
+    // When
+    driver.session();
+  });
+
+  it('should fail nicely when connecting with routing to standalone server', function(done) {
+    // Given
+    var driver = neo4j.driver("bolt+routing://localhost", neo4j.auth.basic("neo4j", "neo4j"));
+
+    // Expect
+    driver.onError = function (err) {
+      expect(err.message).toEqual('Server could not perform routing, make sure you are connecting to a causal cluster');
+      expect(err.code).toEqual(neo4j.error.SERVICE_UNAVAILABLE);
       done();
     };