lxaiobus: import requests on-demand

This matches the approach we have in other drivers already and improves the
startup time of labgrid-client by ~11%.

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>

Author: jluebbe

labgrid/driver/lxaiobusdriver.py

@@ -1,6 +1,6 @@
-import attr
+from importlib import import_module
 
-import requests
+import attr
 
 from ..factory import target_factory
 from ..protocol import DigitalOutputProtocol
@@ -18,6 +18,7 @@ class LXAIOBusPIODriver(Driver, DigitalOutputProtocol):
 
     def __attrs_post_init__(self):
         super().__attrs_post_init__()
+        self._requests = import_module('requests')
 
     def on_activate(self):
         # we can only forward if the backend knows which port to use
@@ -29,7 +30,7 @@ def on_activate(self):
     def set(self, status):
         if self.pio.invert:
             status = not status
-        r = requests.post(
+        r = self._requests.post(
                 self._url, data={'value': '1' if status else '0'}
         )
         r.raise_for_status()
@@ -40,7 +41,7 @@ def set(self, status):
     @Driver.check_active
     @step(result=['True'])
     def get(self):
-        r = requests.get(self._url)
+        r = self._requests.get(self._url)
         r.raise_for_status()
         j = r.json()
         if j["code"] != 0:

labgrid/resource/lxaiobus.py

@@ -1,8 +1,8 @@
 import logging
 from time import monotonic
+from importlib import import_module
 
 import attr
-import requests
 
 from ..factory import target_factory
 from .common import ManagedResource, ResourceManager
@@ -12,18 +12,19 @@
 class LXAIOBusNodeManager(ResourceManager):
     def __attrs_post_init__(self):
         super().__attrs_post_init__()
+        self._requests = import_module('requests')
 
         self.log = logging.getLogger('LXAIOBusNodeManager')
 
         self._last = 0.0
 
     def _get_nodes(self, host):
         try:
-            r = requests.get(f'http://{host}/nodes/')
+            r = self._requests.get(f'http://{host}/nodes/')
             r.raise_for_status()
             j = r.json()
             return j["result"]
-        except requests.exceptions.ConnectionError:
+        except self._requests.exceptions.ConnectionError:
             self.log.exception("failed to connect to host %s", host)
             return []