Use temp dir for server side locks (#4918).

3 files changed, 19 insertions, 3 deletions

diff --git a/common/src/leap/soledad/common/errors.py b/common/src/leap/soledad/common/errors.py
index 62de19f8..c41e0b0f 100644
--- a/common/src/leap/soledad/common/errors.py
+++ b/common/src/leap/soledad/common/errors.py
@@ -67,10 +67,19 @@ class LockTimedOutError(errors.U1DBError):
     status = 408
 
 
+class CouldNotObtainLockError(errors.U1DBError):
+    """
+    Exception raised when timing out while trying to lock the shared database.
+    """
+
+    wire_description = "error obtaining lock"
+    status = 500
+
+
 # update u1db "wire description to status" and "wire description to exception"
 # maps.
 for e in [InvalidTokenError, NotLockedError, AlreadyLockedError,
-        LockTimedOutError]:
+        LockTimedOutError, CouldNotObtainLockError]:
     http_errors.wire_description_to_status.update({
         e.wire_description: e.status})
     errors.wire_description_to_exc.update({
diff --git a/server/changes/feature_4918_use-temporary-directory-for-server-side-locks b/server/changes/feature_4918_use-temporary-directory-for-server-side-locks
new file mode 100644
index 00000000..d8c5ba8e
--- /dev/null
+++ b/server/changes/feature_4918_use-temporary-directory-for-server-side-locks
@@ -0,0 +1 @@
+  o Use a temporary directory for server side locks (#4918).
diff --git a/server/src/leap/soledad/server/__init__.py b/server/src/leap/soledad/server/__init__.py
index 00d3c8c1..4380966c 100644
--- a/server/src/leap/soledad/server/__init__.py
+++ b/server/src/leap/soledad/server/__init__.py
@@ -90,6 +90,7 @@ import configparser
 import time
 import hashlib
 import os
+import tempfile
 
 from u1db.remote import http_app
 
@@ -122,6 +123,7 @@ from leap.soledad.common.errors import (
     NotLockedError,
     AlreadyLockedError,
     LockTimedOutError,
+    CouldNotObtainLockError,
 )
 
 
@@ -201,7 +203,9 @@ class LockResource(object):
         self._shared_db = state.open_database(SoledadApp.SHARED_DB_NAME)
         self._lock_doc_id = '%s%s' % (SHARED_DB_LOCK_DOC_ID_PREFIX, uuid)
         self._lock = FilesystemLock(
-            hashlib.sha512(self._lock_doc_id).hexdigest())
+            os.path.join(
+                tempfile.gettmpdir(),
+                hashlib.sha512(self._lock_doc_id).hexdigest()))
         self._state = state
         self._responder = responder
 
@@ -328,8 +332,10 @@ class LockResource(object):
         while tries > 0:
             try:
                 return self._lock.lock()
-            except Exception as e:
+            except OSError as e:
                 tries -= 1
+                if tries == 0:
+                    raise CouldNotObtainLockError(e.message)
                 time.sleep(self.FILESYSTEM_LOCK_SLEEP_SECONDS)
         return False