Plugin manager gives traceback if no internet connection

[psobolewskiPhD]

If you open the Plugin Manager without an internet connection your get a traceback in the terminal.

URLError: <urlopen error [Errno 8] nodename nor servname provided, or not known>

Instead, a notification should be used to inform the user that they cannot install remote plugins, only local ones.

Full traceback:

---------------------------------------------------------------------------
gaierror                                  Traceback (most recent call last)
File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/urllib/request.py:1348, in AbstractHTTPHandler.do_open(self=<urllib.request.HTTPSHandler object>, http_class=<class 'http.client.HTTPSConnection'>, req=<urllib.request.Request object>, **http_conn_args={'check_hostname': None, 'context': None})
   1347 try:
-> 1348     h.request(req.get_method(), req.selector, req.data, headers,
        h = <http.client.HTTPSConnection object at 0x2948faf10>
        headers = {'Host': 'npe2api.vercel.app', 'User-Agent': 'napari/0.5.0a2.dev543+gad78ee21a runtime/python CPython/3.11.7 Darwin/22.4.0', 'Connection': 'close'}
        req = <urllib.request.Request object at 0x2948e6510>
        req.selector = '/api/conda'
   1349               encode_chunked=req.has_header('Transfer-encoding'))
   1350 except OSError as err: # timeout error

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py:1294, in HTTPConnection.request(self=<http.client.HTTPSConnection object>, method='GET', url='/api/conda', body=None, headers={'Connection': 'close', 'Host': 'npe2api.vercel.app', 'User-Agent': 'napari/0.5.0a2.dev543+gad78ee21a runtime/python CPython/3.11.7 Darwin/22.4.0'}, encode_chunked=False)
   1293 """Send a complete request to the server."""
-> 1294 self._send_request(method, url, body, headers, encode_chunked)
        method = 'GET'
        url = '/api/conda'
        body = None
        headers = {'Host': 'npe2api.vercel.app', 'User-Agent': 'napari/0.5.0a2.dev543+gad78ee21a runtime/python CPython/3.11.7 Darwin/22.4.0', 'Connection': 'close'}
        encode_chunked = False
        self = <http.client.HTTPSConnection object at 0x2948faf10>

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py:1340, in HTTPConnection._send_request(self=<http.client.HTTPSConnection object>, method='GET', url='/api/conda', body=None, headers={'Connection': 'close', 'Host': 'npe2api.vercel.app', 'User-Agent': 'napari/0.5.0a2.dev543+gad78ee21a runtime/python CPython/3.11.7 Darwin/22.4.0'}, encode_chunked=False)
   1339     body = _encode(body, 'body')
-> 1340 self.endheaders(body, encode_chunked=encode_chunked)
        encode_chunked = False
        body = None
        self = <http.client.HTTPSConnection object at 0x2948faf10>

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py:1289, in HTTPConnection.endheaders(self=<http.client.HTTPSConnection object>, message_body=None, encode_chunked=False)
   1288     raise CannotSendHeader()
-> 1289 self._send_output(message_body, encode_chunked=encode_chunked)
        message_body = None
        self = <http.client.HTTPSConnection object at 0x2948faf10>
        encode_chunked = False

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py:1048, in HTTPConnection._send_output(self=<http.client.HTTPSConnection object>, message_body=None, encode_chunked=False)
   1047 del self._buffer[:]
-> 1048 self.send(msg)
        msg = b'GET /api/conda HTTP/1.1\r\nAccept-Encoding: identity\r\nHost: npe2api.vercel.app\r\nUser-Agent: napari/0.5.0a2.dev543+gad78ee21a runtime/python CPython/3.11.7 Darwin/22.4.0\r\nConnection: close\r\n\r\n'
        self = <http.client.HTTPSConnection object at 0x2948faf10>
   1050 if message_body is not None:
   1051 
   1052     # create a consistent interface to message_body

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py:986, in HTTPConnection.send(self=<http.client.HTTPSConnection object>, data=b'GET /api/conda HTTP/1.1\r\nAccept-Encoding: id....11.7 Darwin/22.4.0\r\nConnection: close\r\n\r\n')
    985 if self.auto_open:
--> 986     self.connect()
        self = <http.client.HTTPSConnection object at 0x2948faf10>
    987 else:

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py:1459, in HTTPSConnection.connect(self=<http.client.HTTPSConnection object>)
   1457 "Connect to a host on a given (SSL) port."
-> 1459 super().connect()
   1461 if self._tunnel_host:

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py:952, in HTTPConnection.connect(self=<http.client.HTTPSConnection object>)
    951 sys.audit("http.client.connect", self, self.host, self.port)
--> 952 self.sock = self._create_connection(
        self.sock = None
        self = <http.client.HTTPSConnection object at 0x2948faf10>
        self._create_connection = <function create_connection at 0x101b72f20>
        self.host = 'npe2api.vercel.app'
        self.port = 443
        (self.host,self.port) = ('npe2api.vercel.app', 443)
        self.timeout = <object object at 0x101139920>
        self.source_address = None
    953     (self.host,self.port), self.timeout, self.source_address)
    954 # Might fail in OSs that don't implement TCP_NODELAY

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/socket.py:827, in create_connection(address=('npe2api.vercel.app', 443), timeout=<object object>, source_address=None, all_errors=False)
    826 exceptions = []
--> 827 for res in getaddrinfo(host, port, 0, SOCK_STREAM):
        host = 'npe2api.vercel.app'
        port = 443
        SOCK_STREAM = <SocketKind.SOCK_STREAM: 1>
    828     af, socktype, proto, canonname, sa = res

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/socket.py:962, in getaddrinfo(host='npe2api.vercel.app', port=443, family=0, type=<SocketKind.SOCK_STREAM: 1>, proto=0, flags=0)
    961 addrlist = []
--> 962 for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
        host = 'npe2api.vercel.app'
        port = 443
        family = 0
        type = <SocketKind.SOCK_STREAM: 1>
        proto = 0
        flags = 0
    963     af, socktype, proto, canonname, sa = res

gaierror: [Errno 8] nodename nor servname provided, or not known

During handling of the above exception, another exception occurred:

URLError                                  Traceback (most recent call last)
File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/site-packages/superqt/utils/_qthreading.py:617, in create_worker.<locals>.reraise(e=URLError(gaierror(8, 'nodename nor servname provided, or not known')))
    616 def reraise(e):
--> 617     raise e
        e = URLError(gaierror(8, 'nodename nor servname provided, or not known'))

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/site-packages/superqt/utils/_qthreading.py:178, in WorkerBase.run(self=<napari._qt.qthreading.GeneratorWorker object>)
    176     warnings.filterwarnings("always")
    177     warnings.showwarning = lambda *w: self.warned.emit(w)
--> 178     result = self.work()
        self = <napari._qt.qthreading.GeneratorWorker object at 0x2913e6830>
    179 if isinstance(result, Exception):
    180     if isinstance(result, RuntimeError):
    181         # The Worker object has likely been deleted.
    182         # A deleted wrapped C/C++ object may result in a runtime
    183         # error that will cause segfault if we try to do much other
    184         # than simply notify the user.

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/site-packages/superqt/utils/_qthreading.py:444, in GeneratorWorker.work(self=<napari._qt.qthreading.GeneratorWorker object>)
    442 try:
    443     _input = self._next_value()
--> 444     output = self._gen.send(_input)
        self = <napari._qt.qthreading.GeneratorWorker object at 0x2913e6830>
        _input = None
        self._gen = <generator object iter_napari_plugin_info at 0x291388b80>
    445     self.yielded.emit(output)
    446 except StopIteration as exc:

File ~/Dev/napari/napari/plugins/npe2api.py:93, in iter_napari_plugin_info()
     90     data = executor.submit(plugin_summaries)
     91     _conda = executor.submit(conda_map)
---> 93 conda = _conda.result()
        _conda = <Future at 0x2948e6c10 state=finished raised URLError>
     94 conda_set = {normalized_name(x) for x in conda}
     95 for info in data.result():

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/concurrent/futures/_base.py:449, in Future.result(self=None, timeout=None)
    447     raise CancelledError()
    448 elif self._state == FINISHED:
--> 449     return self.__get_result()
        self = None
    451 self._condition.wait(timeout)
    453 if self._state in [CANCELLED, CANCELLED_AND_NOTIFIED]:

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/concurrent/futures/_base.py:401, in Future.__get_result(self=None)
    399 if self._exception:
    400     try:
--> 401         raise self._exception
        self = None
    402     finally:
    403         # Break a reference cycle with the exception in self._exception
    404         self = None

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/concurrent/futures/thread.py:58, in _WorkItem.run(self=None)
     55     return
     57 try:
---> 58     result = self.fn(*self.args, **self.kwargs)
        self = None
     59 except BaseException as exc:
     60     self.future.set_exception(exc)

File ~/Dev/napari/napari/plugins/npe2api.py:83, in conda_map()
     81 """Return map of PyPI package name to conda_channel/package_name ()."""
     82 url = "https://npe2api.vercel.app/api/conda"
---> 83 with urlopen(Request(url, headers={'User-Agent': _user_agent()})) as resp:
        url = 'https://npe2api.vercel.app/api/conda'
        _user_agent = <functools._lru_cache_wrapper object at 0x2886e9c70>
     84     return json.load(resp)

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/urllib/request.py:216, in urlopen(url=<urllib.request.Request object>, data=None, timeout=<object object>, cafile=None, capath=None, cadefault=False, context=None)
    214 else:
    215     opener = _opener
--> 216 return opener.open(url, data, timeout)
        opener = <urllib.request.OpenerDirector object at 0x2948f8a90>
        url = <urllib.request.Request object at 0x2948e6510>
        data = None
        timeout = <object object at 0x101139920>

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/urllib/request.py:519, in OpenerDirector.open(self=<urllib.request.OpenerDirector object>, fullurl=<urllib.request.Request object>, data=None, timeout=<object object>)
    516     req = meth(req)
    518 sys.audit('urllib.Request', req.full_url, req.data, req.headers, req.get_method())
--> 519 response = self._open(req, data)
        req = <urllib.request.Request object at 0x2948e6510>
        data = None
        self = <urllib.request.OpenerDirector object at 0x2948f8a90>
    521 # post-process response
    522 meth_name = protocol+"_response"

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/urllib/request.py:536, in OpenerDirector._open(self=<urllib.request.OpenerDirector object>, req=<urllib.request.Request object>, data=None)
    533     return result
    535 protocol = req.type
--> 536 result = self._call_chain(self.handle_open, protocol, protocol +
        result = None
        protocol = 'https'
        self.handle_open = {'unknown': [<urllib.request.UnknownHandler object at 0x2948fac50>], 'http': [<urllib.request.HTTPHandler object at 0x17de139d0>], 'ftp': [<urllib.request.FTPHandler object at 0x2948f8710>], 'file': [<urllib.request.FileHandler object at 0x2948f8f90>], 'data': [<urllib.request.DataHandler object at 0x2948f9210>], 'https': [<urllib.request.HTTPSHandler object at 0x2948f9a90>]}
        protocol +
                                  '_open' = 'https_open'
        self = <urllib.request.OpenerDirector object at 0x2948f8a90>
        req = <urllib.request.Request object at 0x2948e6510>
    537                           '_open', req)
    538 if result:
    539     return result

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/urllib/request.py:496, in OpenerDirector._call_chain(self=<urllib.request.OpenerDirector object>, chain={'data': [<urllib.request.DataHandler object>], 'file': [<urllib.request.FileHandler object>], 'ftp': [<urllib.request.FTPHandler object>], 'http': [<urllib.request.HTTPHandler object>], 'https': [<urllib.request.HTTPSHandler object>], 'unknown': [<urllib.request.UnknownHandler object>]}, kind='https', meth_name='https_open', *args=(<urllib.request.Request object>,))
    494 for handler in handlers:
    495     func = getattr(handler, meth_name)
--> 496     result = func(*args)
        func = <bound method HTTPSHandler.https_open of <urllib.request.HTTPSHandler object at 0x2948f9a90>>
        args = (<urllib.request.Request object at 0x2948e6510>,)
    497     if result is not None:
    498         return result

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/urllib/request.py:1391, in HTTPSHandler.https_open(self=<urllib.request.HTTPSHandler object>, req=<urllib.request.Request object>)
   1390 def https_open(self, req):
-> 1391     return self.do_open(http.client.HTTPSConnection, req,
        req = <urllib.request.Request object at 0x2948e6510>
        self = <urllib.request.HTTPSHandler object at 0x2948f9a90>
        http.client = <module 'http.client' from '/Users/piotrsobolewski/Dev/miniforge3/envs/napari-dev/lib/python3.11/http/client.py'>
        self._context = None
        self._check_hostname = None
   1392         context=self._context, check_hostname=self._check_hostname)

File ~/Dev/miniforge3/envs/napari-dev/lib/python3.11/urllib/request.py:1351, in AbstractHTTPHandler.do_open(self=<urllib.request.HTTPSHandler object>, http_class=<class 'http.client.HTTPSConnection'>, req=<urllib.request.Request object>, **http_conn_args={'check_hostname': None, 'context': None})
   1348         h.request(req.get_method(), req.selector, req.data, headers,
   1349                   encode_chunked=req.has_header('Transfer-encoding'))
   1350     except OSError as err: # timeout error
-> 1351         raise URLError(err)
   1352     r = h.getresponse()
   1353 except:

URLError: <urlopen error [Errno 8] nodename nor servname provided, or not known>