Allow to authenticate to Gerrit with HTTP basic auth

Gerrit instances running at googlesource.com require authentication
with HTTP basic auth.

Add a new config option to allow to specify either basic auth or digest
auth. Default to digest auth if not specified.

Change-Id: Iab6f666082bd3fee2c77a8c489255926cc93edba
Closes-Bug: 291

examples/reference-gertty.yaml

@@ -23,6 +23,10 @@ servers:
 #    username: CHANGEME
 # Your password in Gerrit (Settings -> HTTP Password). [required]
 #    password: CHANGEME
+# Authentication type required by the Gerrit server. Can be 'basic' or
+# 'digest'. Defaults to 'digest' if not set or set to an unexpected
+# value.
+#    auth-type: digest
 # A location where Gertty should store its git repositories.  These
 # can be the same git repositories where you do your own work --
 # Gertty will not modify them unless you tell it to, and even then the

gertty/config.py

@@ -45,6 +45,7 @@ class ConfigSchema(object):
               'dburi': str,
               v.Required('git-root'): str,
               'log-file': str,
+              'auth-type': str,
               }
 
     servers = [server]
@@ -133,6 +134,10 @@ class Config(object):
         if self.password is None:
             self.password = getpass.getpass("Password for %s (%s): "
                                             % (self.url, self.username))
+        self.auth_type = server.get('auth-type', 'digest')
+        auth_types = ['digest', 'basic']
+        if self.auth_type not in auth_types:
+            self.auth_type = 'digest'
         self.verify_ssl = server.get('verify-ssl', True)
         if not self.verify_ssl:
             os.environ['GIT_SSL_NO_VERIFY']='true'

gertty/sync.py

@@ -762,7 +762,11 @@ class Sync(object):
         self.log = logging.getLogger('gertty.sync')
         self.queue = MultiQueue([HIGH_PRIORITY, NORMAL_PRIORITY, LOW_PRIORITY])
         self.session = requests.Session()
-        self.auth = requests.auth.HTTPDigestAuth(
+        if self.app.config.auth_type == 'basic':
+            authclass = requests.auth.HTTPBasicAuth
+        else:
+            authclass = requests.auth.HTTPDigestAuth
+        self.auth = authclass(
             self.app.config.username, self.app.config.password)
         self.submitTask(SyncOwnAccountTask(HIGH_PRIORITY))
         self.submitTask(CheckReposTask(HIGH_PRIORITY))