routing: Fix default database name in the routing connection provider

A RoutingTableRegistry was extracted from the Connection Provider to help re-use
some behaviours.

Author: bigmontz

src/internal/connection-provider-routing.js

@@ -63,7 +63,6 @@ export default class RoutingConnectionProvider extends PooledConnectionProvider
     })
 
     this._seedRouter = address
-    this._routingTables = {}
     this._rediscovery = new Rediscovery(routingContext, address.toString())
     this._loadBalancingStrategy = new LeastConnectedLoadBalancingStrategy(
       this._connectionPool
@@ -72,9 +71,11 @@ export default class RoutingConnectionProvider extends PooledConnectionProvider
     this._dnsResolver = new HostNameResolver()
     this._log = log
     this._useSeedRouter = true
-    this._routingTablePurgeDelay = routingTablePurgeDelay
-      ? int(routingTablePurgeDelay)
-      : DEFAULT_ROUTING_TABLE_PURGE_DELAY
+    this._routingTableRegistry = new RoutingTableRegistry(
+      routingTablePurgeDelay
+        ? int(routingTablePurgeDelay)
+        : DEFAULT_ROUTING_TABLE_PURGE_DELAY
+    )
   }
 
   _createConnectionErrorHandler () {
@@ -87,15 +88,15 @@ export default class RoutingConnectionProvider extends PooledConnectionProvider
     this._log.warn(
       `Routing driver ${this._id} will forget ${address} for database '${database}' because of an error ${error.code} '${error.message}'`
     )
-    this.forget(address, database || '')
+    this.forget(address, database || DEFAULT_DB_NAME)
     return error
   }
 
   _handleWriteFailure (error, address, database) {
     this._log.warn(
       `Routing driver ${this._id} will forget writer ${address} for database '${database}' because of an error ${error.code} '${error.message}'`
     )
-    this.forgetWriter(address, database || '')
+    this.forgetWriter(address, database || DEFAULT_DB_NAME)
     return newError(
       'No longer possible to write to server at ' + address,
       SESSION_EXPIRED
@@ -206,36 +207,30 @@ export default class RoutingConnectionProvider extends PooledConnectionProvider
   }
 
   forget (address, database) {
-    if (database || database === '') {
-      this._routingTables[database].forget(address)
-    } else {
-      Object.values(this._routingTables).forEach(routingTable =>
-        routingTable.forget(address)
-      )
-    }
+    this._routingTableRegistry.apply(database, {
+      applyWhenExists: routingTable => routingTable.forget(address)
+    })
 
     // We're firing and forgetting this operation explicitly and listening for any
     // errors to avoid unhandled promise rejection
     this._connectionPool.purge(address).catch(() => {})
   }
 
   forgetWriter (address, database) {
-    if (database || database === '') {
-      this._routingTables[database].forgetWriter(address)
-    } else {
-      Object.values(this._routingTables).forEach(routingTable =>
-        routingTable.forgetWriter(address)
-      )
-    }
+    this._routingTableRegistry.apply(database, {
+      applyWhenExists: routingTable => routingTable.forgetWriter(address)
+    })
   }
 
   _acquireConnectionToServer (address, serverName, routingTable) {
     return this._connectionPool.acquire(address)
   }
 
   _freshRoutingTable ({ accessMode, database, bookmark } = {}) {
-    const currentRoutingTable =
-      this._routingTables[database] || new RoutingTable({ database })
+    const currentRoutingTable = this._routingTableRegistry.get(
+      database,
+      () => new RoutingTable({ database })
+    )
 
     if (!currentRoutingTable.isStaleFor(accessMode)) {
       return currentRoutingTable
@@ -481,16 +476,11 @@ export default class RoutingConnectionProvider extends PooledConnectionProvider
   async _updateRoutingTable (newRoutingTable) {
     // close old connections to servers not present in the new routing table
     await this._connectionPool.keepAll(newRoutingTable.allServers())
-
-    // filter out expired to purge (expired for a pre-configured amount of time) routing table entries
-    Object.values(this._routingTables).forEach(value => {
-      if (value.isExpiredFor(this._routingTablePurgeDelay)) {
-        delete this._routingTables[value.database]
-      }
-    })
-
-    // make this driver instance aware of the new table
-    this._routingTables[newRoutingTable.database] = newRoutingTable
+    this._routingTableRegistry.removeExpired()
+    this._routingTableRegistry.register(
+      newRoutingTable.database,
+      newRoutingTable
+    )
     this._log.info(`Updated routing table ${newRoutingTable}`)
   }
 
@@ -501,3 +491,96 @@ export default class RoutingConnectionProvider extends PooledConnectionProvider
     }
   }
 }
+
+/**
+ * Responsible for keeping track of the existing routing tables
+ */
+class RoutingTableRegistry {
+  /**
+   * Constructor
+   * @param {int} routingTablePurgeDelay The routing table purge delay
+   */
+  constructor (routingTablePurgeDelay) {
+    this._tables = new Map()
+    this._routingTablePurgeDelay = routingTablePurgeDelay
+  }
+
+  /**
+   * Put a routing table in the registry
+   *
+   * @param {string} database The database name
+   * @param {RoutingTable} table The routing table
+   * @returns {RoutingTableRegistry} this
+   */
+  register (database, table) {
+    this._tables.set(database, table)
+    return this
+  }
+
+  /**
+   * Apply function in the routing table for an specific database. If the database name is not defined, the function will
+   * be applied for each element
+   *
+   * @param {string} database The database name
+   * @param {object} callbacks The actions
+   * @param {function (RoutingTable)} callbacks.applyWhenExists Call when the db exists or when the database property is not informed
+   * @param {function ()} callbacks.applyWhenDontExists Call when the database doesn't have the routing table registred
+   * @returns {RoutingTableRegistry} this
+   */
+  apply (database, { applyWhenExists, applyWhenDontExists = () => {} } = {}) {
+    if (this._tables.has(database)) {
+      applyWhenExists(this._tables.get(database))
+    } else if (typeof database === 'string' || database === null) {
+      applyWhenDontExists()
+    } else {
+      this._forEach(applyWhenExists)
+    }
+    return this
+  }
+
+  /**
+   * Retrieves a routing table from a given database name
+   * @param {string} database The database name
+   * @param {function()|RoutingTable} defaultSupplier The routing table supplier, if it's not a function or not exists, it will return itself as default value
+   * @returns {RoutingTable} The routing table for the respective database
+   */
+  get (database, defaultSupplier) {
+    if (this._tables.has(database)) {
+      return this._tables.get(database)
+    }
+    return typeof defaultSupplier === 'function'
+      ? defaultSupplier()
+      : defaultSupplier
+  }
+
+  /**
+   * Remove the routing table which is already expired
+   * @returns {RoutingTableRegistry} this
+   */
+  removeExpired () {
+    return this._removeIf(value =>
+      value.isExpiredFor(this._routingTablePurgeDelay)
+    )
+  }
+
+  _forEach (apply) {
+    for (const [, value] of this._tables) {
+      apply(value)
+    }
+    return this
+  }
+
+  _remove (key) {
+    this._tables.delete(key)
+    return this
+  }
+
+  _removeIf (predicate) {
+    for (const [key, value] of this._tables) {
+      if (predicate(value)) {
+        this._remove(key)
+      }
+    }
+    return this
+  }
+}

test/internal/connection-provider-routing.test.js

@@ -1677,6 +1677,99 @@ describe('#unit RoutingConnectionProvider', () => {
       )
     })
 
+    it('should forget write server from the default database routing table on availability error', async () => {
+      const pool = newPool()
+      const connectionProvider = newRoutingConnectionProvider(
+        [
+          newRoutingTable(
+            'databaseA',
+            [server1, server2, server3],
+            [server1, server2],
+            [server3]
+          ),
+          newRoutingTable(
+            null,
+            [serverA, serverB, serverC],
+            [serverA, serverB],
+            [serverA, serverC]
+          )
+        ],
+        pool
+      )
+
+      const conn1 = await connectionProvider.acquireConnection({
+        accessMode: WRITE,
+        database: null
+      })
+
+      // when
+      conn1._errorHandler.handleAndTransformError(
+        newError('connection error', SERVICE_UNAVAILABLE),
+        conn1.address
+      )
+
+      expectRoutingTable(
+        connectionProvider,
+        'databaseA',
+        [server1, server2, server3],
+        [server1, server2],
+        [server3]
+      )
+      expectRoutingTable(
+        connectionProvider,
+        null,
+        [serverA, serverB, serverC],
+        [serverB],
+        [serverC]
+      )
+    })
+
+    it('should forget write server from the default database routing table on availability error when db not informed', async () => {
+      const pool = newPool()
+      const connectionProvider = newRoutingConnectionProvider(
+        [
+          newRoutingTable(
+            'databaseA',
+            [server1, server2, server3],
+            [server1, server2],
+            [server3]
+          ),
+          newRoutingTable(
+            null,
+            [serverA, serverB, serverC],
+            [serverA, serverB],
+            [serverA, serverC]
+          )
+        ],
+        pool
+      )
+
+      const conn1 = await connectionProvider.acquireConnection({
+        accessMode: WRITE
+      })
+
+      // when
+      conn1._errorHandler.handleAndTransformError(
+        newError('connection error', SERVICE_UNAVAILABLE),
+        conn1.address
+      )
+
+      expectRoutingTable(
+        connectionProvider,
+        'databaseA',
+        [server1, server2, server3],
+        [server1, server2],
+        [server3]
+      )
+      expectRoutingTable(
+        connectionProvider,
+        null,
+        [serverA, serverB, serverC],
+        [serverB],
+        [serverC]
+      )
+    })
+
     it('should forget write server from correct routing table on write error', async () => {
       const pool = newPool()
       const connectionProvider = newRoutingConnectionProvider(
@@ -1847,7 +1940,7 @@ function newRoutingConnectionProviderWithSeedRouter (
   })
   connectionProvider._connectionPool = pool
   routingTables.forEach(r => {
-    connectionProvider._routingTables[r.database] = r
+    connectionProvider._routingTableRegistry.register(r.database, r)
   })
   connectionProvider._rediscovery = new FakeRediscovery(routerToRoutingTable)
   connectionProvider._hostNameResolver = new FakeDnsResolver(seedRouterResolved)
@@ -1903,14 +1996,15 @@ function expectRoutingTable (
   readers,
   writers
 ) {
-  expect(connectionProvider._routingTables[database].database).toEqual(database)
-  expect(connectionProvider._routingTables[database].routers).toEqual(routers)
-  expect(connectionProvider._routingTables[database].readers).toEqual(readers)
-  expect(connectionProvider._routingTables[database].writers).toEqual(writers)
+  const routingTable = connectionProvider._routingTableRegistry.get(database)
+  expect(routingTable.database).toEqual(database)
+  expect(routingTable.routers).toEqual(routers)
+  expect(routingTable.readers).toEqual(readers)
+  expect(routingTable.writers).toEqual(writers)
 }
 
 function expectNoRoutingTable (connectionProvider, database) {
-  expect(connectionProvider._routingTables[database]).toBeFalsy()
+  expect(connectionProvider._routingTableRegistry.get(database)).toBeFalsy()
 }
 
 function expectPoolToContain (pool, addresses) {