Renamed attract_server → attract

attract/subversion.py

@@ -0,0 +1,65 @@
+"""Subversion interface."""
+
+from __future__ import absolute_import
+
+import re
+
+import attr
+import blinker
+import svn.remote
+import svn.common
+
+from . import attrs_extra
+
+task_logged = blinker.NamedSignal('task_logged')
+task_marker_re = re.compile(r'\[(?P<task_id>T\d+)\]')
+
+
+def obtain(server_location):
+    """Returns a Connection object for the given server location."""
+
+    return svn.remote.RemoteClient(server_location)
+
+
+@attr.s
+class CommitLogObserver(object):
+    svn_client = attr.ib(validator=attr.validators.instance_of(svn.remote.RemoteClient))
+    last_seen_revision = attr.ib(default=0, validator=attr.validators.instance_of(int))
+    _log = attrs_extra.log('%s.CommitLogObserver' % __name__)
+
+    def fetch_and_observe(self):
+        """Obtains task IDs from SVN logs."""
+
+        self._log.debug('%s: fetch_and_observe()', self)
+
+        try:
+            svn_log = self.svn_client.log_default(revision_from=self.last_seen_revision + 1)
+            for log_entry in svn_log:
+                self._log.debug('- %r', log_entry)
+
+                # assumption: revisions are always logged in strictly increasing order.
+                self.last_seen_revision = log_entry.revision
+
+                self._parse_log_entry(log_entry)
+        except svn.common.SvnCommandError:
+            # The SVN library just raises a SvnCommandError when something goes wrong,
+            # without any structured indication of the error. There isn't much else
+            # we can do, except to log the error and return.
+            self._log.exception('Error calling self.svn_client.log_default()')
+            return
+
+    def _parse_log_entry(self, log_entry):
+        """Parses the commit log to see if there are any task markers."""
+
+        # Log entries can be None.
+        if not log_entry.msg:
+            return
+
+        # Parse the commit log to see if there are any task markers.
+        lines = log_entry.msg.split('\n', 1)
+        first_line = lines[0]
+        for match in task_marker_re.finditer(first_line):
+            task_id = match.group('task_id')
+
+            # Send a Blinker signal for each observed task identifier.
+            task_logged.send(self, task_id=task_id, log_entry=log_entry)