[FIX] hw_*: enforce Python dependencies + disable if missing dependency

Prevents installing the hw_* modules at all when the python
dependencies are missing. If they were already installed
do not start the hardware threads to avoid wasting resources
and logging errors

addons/hw_scale/__openerp__.py

@@ -37,6 +37,7 @@ such as the Mettler Toledo Ariva.
 """,
     'author': 'OpenERP SA',
     'depends': ['hw_proxy'],
+    'external_dependencies': {'python': ['serial']},
     'test': [
     ],
     'installable': True,

addons/hw_scale/controllers/main.py

@@ -178,28 +178,34 @@ class Scale(Thread):
                 if not self.device:
                     time.sleep(5)
 
-s = Scale()
+scale_thread = None
-
+if serial:
-hw_proxy.drivers['scale'] = s
+    scale_thread = Scale()
+    hw_proxy.drivers['scale'] = scale_thread
 
 class ScaleDriver(hw_proxy.Proxy):
     @http.route('/hw_proxy/scale_read/', type='json', auth='none', cors='*')
     def scale_read(self):
-        return {'weight':s.get_weight(), 'unit':'kg', 'info':s.get_weight_info()}
+        if scale_thread:
+            return {'weight': scale_thread.get_weight(), 'unit':'kg', 'info': scale_thread.get_weight_info()}
+        return None
 
     @http.route('/hw_proxy/scale_zero/', type='json', auth='none', cors='*')
     def scale_zero(self):
-        s.set_zero()
+        if scale_thread:
+            scale_thread.set_zero()
         return True
 
     @http.route('/hw_proxy/scale_tare/', type='json', auth='none', cors='*')
     def scale_tare(self):
-        s.set_tare()
+        if scale_thread:
+            scale_thread.set_tare()
         return True
 
     @http.route('/hw_proxy/scale_clear_tare/', type='json', auth='none', cors='*')
     def scale_clear_tare(self):
-        s.clear_tare()
+        if scale_thread:
+            scale_thread.clear_tare()
         return True
         
         

addons/hw_scanner/__openerp__.py

@@ -38,6 +38,7 @@ point of sale module.
 """,
     'author': 'OpenERP SA',
     'depends': ['hw_proxy'],
+    'external_dependencies': {'python': ['evdev']},
     'test': [
     ],
     'installable': True,

addons/hw_scanner/controllers/main.py

@@ -111,8 +111,6 @@ class Scanner(Thread):
 
     def get_device(self):
         try:
-            if not evdev:
-                return None
             devices   = [ device for device in listdir(self.input_dir)]
             keyboards = [ device for device in devices if ('kbd' in device) and ('keyboard' not in device.lower())]
             scanners  = [ device for device in devices if ('barcode' in device.lower()) or ('scanner' in device.lower())]
@@ -135,7 +133,6 @@ class Scanner(Thread):
             been returned before. This is necessary to catch barcodes scanned while the POS is
             busy reading another barcode
         """
-
         self.lockedstart()
 
         while True:
@@ -204,12 +201,12 @@ class Scanner(Thread):
             except Exception as e:
                 self.set_status('error',str(e))
 
-s = Scanner()
+scanner_thread = None
-
+if evdev:
-hw_proxy.drivers['scanner'] = s
+    scanner_thread = Scanner()
+    hw_proxy.drivers['scanner'] = scanner_thread
 
 class ScannerDriver(hw_proxy.Proxy):
     @http.route('/hw_proxy/scanner', type='json', auth='none', cors='*')
-    def scanner(self):
+    def scanner_thread(self):
-        return s.get_barcode()
+        return scanner_thread.get_barcode() if scanner_thread else None
-