bitbake: prserv/cooker: Handle PRService errors cleanly

Current if the PR Service fails to start, bitbake carries on regardless or
hangs with no error message. This adds an exception and then handles it correctly
so the UIs correctly handle the error and exit cleanly.

[YOCTO #4010]

(Bitbake rev: 949c01228a977c3b92bfc0802f6c71b40d8e05b3)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/cooker.py

@@ -1486,7 +1486,10 @@ class BBCooker:
         # Empty the environment. The environment will be populated as
         # necessary from the data store.
         #bb.utils.empty_environment()
-        prserv.serv.auto_start(self.configuration.data)
+        try:
+            prserv.serv.auto_start(self.configuration.data)
+        except prserv.serv.PRServiceConfigError:
+            bb.event.fire(CookerExit(), self.configuration.event_data)
         return
 
     def post_serve(self):

bitbake/lib/prserv/serv.py

@@ -263,6 +263,9 @@ def is_local_special(host, port):
     else:
         return False
 
+class PRServiceConfigError(Exception):
+    pass
+
 def auto_start(d):
     global singleton
 
@@ -273,14 +276,14 @@ def auto_start(d):
     if len(host_params) != 2:
         logger.critical('\n'.join(['PRSERV_HOST: incorrect format',
                 'Usage: PRSERV_HOST = "<hostname>:<port>"']))
-        return True
+        raise PRServiceConfigError
 
     if is_local_special(host_params[0], int(host_params[1])) and not singleton:
         import bb.utils
         cachedir = (d.getVar("PERSISTENT_DIR", True) or d.getVar("CACHE", True))
         if not cachedir:
             logger.critical("Please set the 'PERSISTENT_DIR' or 'CACHE' variable")
-            sys.exit(1)
+            raise PRServiceConfigError
         bb.utils.mkdirhier(cachedir)
         dbfile = os.path.join(cachedir, "prserv.sqlite3")
         logfile = os.path.join(cachedir, "prserv.log")
@@ -296,7 +299,7 @@ def auto_start(d):
         return PRServerConnection(host,port).ping()
     except Exception:
         logger.critical("PRservice %s:%d not available" % (host, port))
-    return False
+        raise PRServiceConfigError
 
 def auto_shutdown(d=None):
     global singleton