Better IMAP Error handling

packages/nylas-api/routes/auth.js

@@ -9,6 +9,7 @@ const {
   DatabaseConnector,
   SyncPolicy,
   Provider,
+  Errors,
 } = require('nylas-core');
 
 const {GMAIL_CLIENT_ID, GMAIL_CLIENT_SECRET, GMAIL_REDIRECT_URL} = process.env;
@@ -162,7 +163,8 @@ module.exports = (server) => {
         reply(Serialization.jsonStringify(response));
       })
       .catch((err) => {
-        reply({error: err.message}).code(400);
+        const code = err instanceof Errors.IMAPAuthenticationError ? 401 : 400
+        reply({message: err.message, type: "api_error"}).code(code);
       })
     },
   });
@@ -204,13 +206,13 @@ module.exports = (server) => {
       const oauthClient = new OAuth2(GMAIL_CLIENT_ID, GMAIL_CLIENT_SECRET, GMAIL_REDIRECT_URL);
       oauthClient.getToken(request.query.code, (err, tokens) => {
         if (err) {
-          reply({error: err.message}).code(400);
+          reply({message: err.message, type: "api_error"}).code(400);
           return;
         }
         oauthClient.setCredentials(tokens);
         google.oauth2({version: 'v2', auth: oauthClient}).userinfo.get((error, profile) => {
           if (error) {
-            reply({error: error.message}).code(400);
+            reply({message: error.message, type: "api_error"}).code(400);
             return;
           }
 
@@ -247,7 +249,7 @@ module.exports = (server) => {
             reply(Serialization.jsonStringify(response));
           })
           .catch((connectionErr) => {
-            reply({error: connectionErr.message}).code(400);
+            reply({message: connectionErr.message, type: "api_error"}).code(400);
           });
         });
       });

packages/nylas-api/serialization.js

@@ -11,6 +11,12 @@ function jsonSchema(modelName) {
   if (models.includes(modelName)) {
     return Joi.object();
   }
+  if (modelName === 'Error') {
+    return Joi.object().keys({
+      message: Joi.string(),
+      type: Joi.string(),
+    })
+  }
   if (modelName === 'Account') {
     // Ben: Disabled temporarily because folks keep changing the keys and it's hard
     // to keep in sync. Might need to consider another approach to these.

packages/nylas-core/imap-connection.js

@@ -5,6 +5,7 @@ const EventEmitter = require('events');
 
 const IMAPBox = require('./imap-box');
 const {
+  convertImapError,
   IMAPConnectionNotReadyError,
   IMAPConnectionEndedError,
 } = require('./imap-errors');
@@ -111,7 +112,7 @@ class IMAPConnection extends EventEmitter {
 
       this._imap.once('error', (err) => {
         this.end();
-        reject(err);
+        reject(convertImapError(err));
       });
 
       this._imap.once('end', () => {

packages/nylas-core/imap-errors.js

@@ -1,21 +1,100 @@
+/**
+ * Errors may come from:
+ *
+ * 1. Underlying IMAP provider (Fastmail, Yahoo, etc)
+ * 2. Node IMAP
+ * 3. K2 code
+ *
+ * NodeIMAP puts a `source` attribute on `Error` objects to indicate where
+ * a particular error came from. See https://github.com/mscdex/node-imap/blob/master/lib/Connection.js
+ *
+ * These may have the following values:
+ *
+ *   - "socket-timeout": Created by NodeIMAP when `config.socketTimeout`
+ *     expires on the base Node `net.Socket` and socket.on('timeout') fires
+ *     Message: 'Socket timed out while talking to server'
+ *
+ *   - "timeout": Created by NodeIMAP when `config.connTimeout` has been
+ *     reached when trying to connect the socket.
+ *     Message: 'Timed out while connecting to server'
+ *
+ *   - "socket": Created by Node's `net.Socket` on error. See:
+ *     https://nodejs.org/api/net.html#net_event_error_1
+ *     Message: Various from `net.Socket`
+ *
+ *   - "protocol": Created by NodeIMAP when `bad` or `no` types come back
+ *     from the IMAP protocol.
+ *     Message: Various from underlying IMAP protocol
+ *
+ *   - "authentication": Created by underlying IMAP connection or NodeIMAP
+ *     in a few scenarios.
+ *     Message: Various from underlying IMAP connection
+ *              OR: No supported authentication method(s) available. Unable to login.
+ *              OR: Logging in is disabled on this server
+ *
+ *   - "timeout-auth": Created by NodeIMAP when `config.authTimeout` has
+ *     been reached when trying to authenticate
+ *     Message: 'Timed out while authenticating with server'
+ *
+ */
+function convertImapError(imapError) {
+  let error;
+  switch(imapError.source) {
+    case "socket-timeout":
+      error = new IMAPConnectionTimeoutError(imapError); break;
+    case "timeout":
+      error = new IMAPConnectionTimeoutError(imapError); break;
+    case "socket":
+      error = new IMAPSocketError(imapError); break;
+    case "protocol":
+      error = new IMAPProtocolError(imapError); break;
+    case "authentication":
+      error = new IMAPAuthenticationError(imapError); break;
+    case "timeout-auth":
+      error = new IMAPAuthenticationTimeoutError(imapError); break;
+    default:
+      return error
+  }
+  error.source = imapError.source
+  return error
+}
 
-// "Source" is a hack so that the error matches the ones used by node-imap
+/**
+ * An abstract base class that can be used to indicate errors that may fix
+ * themselves when retried
+ */
+class RetryableError extends Error {  }
 
-class IMAPConnectionNotReadyError extends Error {
+/**
+ * Errors that originate from NodeIMAP. See `convertImapError` for
+ * documentation on underlying causes
+ */
+class IMAPSocketError extends RetryableError { }
+class IMAPConnectionTimeoutError extends RetryableError { }
+class IMAPAuthenticationTimeoutError extends RetryableError { }
+class IMAPProtocolError extends Error { }
+class IMAPAuthenticationError extends Error { }
+
+class IMAPConnectionNotReadyError extends RetryableError {
   constructor(funcName) {
     super(`${funcName} - You must call connect() first.`);
-    this.source = 'socket';
   }
 }
 
 class IMAPConnectionEndedError extends Error {
   constructor(msg = "The IMAP Connection was ended.") {
     super(msg);
-    this.source = 'socket';
   }
 }
 
 module.exports = {
+  convertImapError,
+  RetryableError,
+  IMAPSocketError,
+  IMAPConnectionTimeoutError,
+  IMAPAuthenticationTimeoutError,
+  IMAPProtocolError,
+  IMAPAuthenticationError,
   IMAPConnectionNotReadyError,
   IMAPConnectionEndedError,
 };

packages/nylas-core/index.js

@@ -12,4 +12,5 @@ module.exports = {
   SchedulerUtils: require('./scheduler-utils'),
   MessageTypes: require('./message-types'),
   Logger: require('./logger'),
+  Errors: require('./imap-errors'),
 }

packages/nylas-sync/sync-worker.js

@@ -4,6 +4,7 @@ const {
   PubsubConnector,
   DatabaseConnector,
   MessageTypes,
+  Errors,
 } = require('nylas-core');
 const {
   jsonError,
@@ -200,7 +201,7 @@ class SyncWorker {
     this.closeConnection()
 
     // Continue to retry if it was a network error
-    if (error.source && (error.source.includes('socket') || error.source.includes('timeout'))) {
+    if (error instanceof Errors.RetryableError) {
       return Promise.resolve()
     }