An unreachable appstore stops the API from returning a reply

Expected behavior

The external monitor API should always return a reply. If some information, like e.g. the number of available app updates couldn't be evaluated, it should jump over this information instead of aborting its function at all.

Current behavior

The external monitor API, which by default also shows information about available app updates, doesn't return a reply at all if the app store is unreachable, for whatever reason.

Steps to reproduce

1. The app store is temporarily unreachable

2. Execute the API call, like e.g.

   curl -s -m 5 -k --netrc https://<nextcloud-fqdn>/ocs/v2.php/apps/serverinfo/api/v1/info
   

   => The request will most likely not return any output.

3. Check the Nextcloud log file for information about the request.

4. You will most likely find an entry with the following content:

   {
     "reqId": "JKOFfevzZHTTOKCGEFqJ7",
     "level": 1,
     "time": "2019-02-22 13:08:47+01:00",
     "remoteAddr": "<nc-server-ip>",
     "user": "<nc-user>",
     "app": "appstoreFetcher",
     "method": "GET",
     "url": "/ocs/v2.php/apps/serverinfo/api/v1/info",
     "message": {
       "Exception": "GuzzleHttp\\Exception\\ConnectException",
       "Message": "cURL error 28: Connection timed out after 10004 milliseconds (see http://curl.haxx.se/libcurl/c/libcurl-errors.html)",
       "Code": 0,
   

   . ^^^ the connection timed out! ^^^

       "Trace": [
         {
           "file": "<path-to-nc-root>/nextcloud/3rdparty/guzzlehttp/guzzle/src/Handler/CurlFactory.php",
           "line": 149,
           "function": "createRejection",
           "class": "GuzzleHttp\\Handler\\CurlFactory",
           "type": "::",
           "args": [
             {
               "sink": {
                 "__class__": "GuzzleHttp\\Psr7\\Stream"
               },
               "headers": [],
               "response": null,
               "request": {
                 "__class__": "GuzzleHttp\\Psr7\\Request"
               },
   
         ...
   
         {
           "file": "<path-to-nc-root>/nextcloud/ocs/v1.php",
           "line": 82,
           "function": "match",
           "class": "OC\\Route\\Router",
           "type": "->",
           "args": [
             "/ocsapp/apps/serverinfo/api/v1/info"
           ]
         },
         {
           "file": "<path-to-nc-root>/nextcloud/ocs/v2.php",
           "line": 24,
           "args": [
             "<path-to-nc-root>/nextcloud/ocs/v1.php"
           ],
           "function": "require_once"
         }
       ],
       "File": "<path-to-nc-root>/nextcloud/3rdparty/guzzlehttp/guzzle/src/Handler/CurlFactory.php",
       "Line": 185,
       "CustomMessage": "Could not connect to appstore"
   

   . ^^^ the appstore was unreachable! ^^^

     },
     "userAgent": "curl/7.63.0",
     "version": "15.0.4.0"
   }
   
   

Environment

Server Configuration

OS: Linux 3.16.62
Web server: Apache2 2.4.37
Database: MariaDB 10.2.21
PHP version: 7.2.14
Nextcloud version: 15.0.4
Serverinfo app version: 1.5.0

Client Configuration

Browser: Mozilla Firefox 65.0.1
Operating system: Windows 10

Start by reproducing the curl request against /ocs/v2.php/apps/serverinfo/api/v1/info while the app store is unreachable, then trace the appstoreFetcher path associated with that endpoint. Done means the API returns a reply with available information while skipping app-update data when the app store connection times out.