Add a timeout to outbound requests (#6075)

There have been instances where the outbound request handler has hung
completely in production. It's not clear from logging why this occured
and it's not consistent or repeatable, but a good potential option is
that requests to external servers are hanging.

This change adds an explicit timeout to the two outbound IO requests.

Depending on various factors there may already be an implicit timeout,
but this makes it explicit and much shorter (10 seconds).

#6025

sentinel/src/schedule/outbound.js

@@ -11,6 +11,7 @@ const configService = require('../config'),
       lineage = require('@medic/lineage')(Promise, db.medic);
 
 const CONFIGURED_PUSHES = 'outbound';
+const OUTBOUND_REQ_TIMEOUT = 10 * 1000;
 
 const fetchPassword = key => {
   return secureSettings.getCredentials(key).then(password => {
@@ -24,8 +25,8 @@ const fetchPassword = key => {
 // Returns an object containing:
 //   validTasks: an array of tasks and their hydrated docs as {task doc} objects
 //   invalidTasks: an array of tasks whose documents have been deleted
-const queuedTasks = () =>
-  db.sentinel.allDocs({
+const queuedTasks = () => {
+  return db.sentinel.allDocs({
     startkey: 'task:outbound:',
     endkey: 'task:outbound:\ufff0',
     include_docs: true
@@ -71,6 +72,7 @@ const queuedTasks = () =>
       }
     });
   });
+};
 
 // Maps a source document to a destination format using the given push config
 const mapDocumentToPayload = (doc, config, key) => {
@@ -129,7 +131,8 @@ const send = (payload, config) => {
   const sendOptions = {
     url: urlJoin(config.destination.base_url, config.destination.path),
     body: payload,
-    json: true
+    json: true,
+    timeout: OUTBOUND_REQ_TIMEOUT
   };
 
   const auth = () => {
@@ -163,7 +166,8 @@ const send = (payload, config) => {
               password: password
             },
             url: urlJoin(config.destination.base_url, authConf.path),
-            json: true
+            json: true,
+            timeout: OUTBOUND_REQ_TIMEOUT
           };
 
           return request.post(authOptions)