From 92c83b2b2ef7877bd448329cad5138da7746c8bf Mon Sep 17 00:00:00 2001
From: mengalong <alongmeng@gmail.com>
Date: Tue, 4 Apr 2017 18:02:32 +0800
Subject: [PATCH] Implement heartbeat for FileDriver

As the title said this patch just implement the heartbeat api for
FileDriver.
1. You can delivery the parameter 'timeout' via the connect url like
   this: file:///tmp/test_coord?timeout=10. Otherwise the default timeout
   is 10secs.
2. We can call the function: heartbeat(self) periodic
   to make sure the specific member is alive.
3. When you call get_members(), it will compare the last modify time of
   the file with current time, if the delta_seconds greater than
   the timeout, it will mark the member status is dead and will not return
   the member_id.

Change-Id: I8617e17fc1a74e70d7eb5b6f8e12dc9d9a66c755
Closes-Bug: #1664559
---
 tooz/drivers/file.py | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/tooz/drivers/file.py b/tooz/drivers/file.py
index 45e5230b..99626692 100644
--- a/tooz/drivers/file.py
+++ b/tooz/drivers/file.py
@@ -232,6 +232,8 @@ class FileDriver(coordination.CoordinationDriverCachedRunWatchers):
         self._reserved_paths = list(self._reserved_dirs)
         self._reserved_paths.append(self._driver_lock_path)
         self._safe_member_id = self._make_filesystem_safe(member_id)
+        self._options = utils.collapse(options)
+        self._timeout = int(self._options.get('timeout', 10))
 
     @staticmethod
     def _normalize_path(path):
@@ -405,7 +407,15 @@ class FileDriver(coordination.CoordinationDriverCachedRunWatchers):
                         continue
                     entry_path = os.path.join(group_dir, entry)
                     try:
-                        member_id = self._read_member_id(entry_path)
+                        m_time = datetime.datetime.fromtimestamp(
+                            os.stat(entry_path).st_mtime)
+                        current_time = datetime.datetime.now()
+                        delta_time = timeutils.delta_seconds(m_time,
+                                                             current_time)
+                        if delta_time >= 0 and delta_time <= self._timeout:
+                            member_id = self._read_member_id(entry_path)
+                        else:
+                            continue
                     except EnvironmentError as e:
                         if e.errno != errno.ENOENT:
                             raise
@@ -497,6 +507,23 @@ class FileDriver(coordination.CoordinationDriverCachedRunWatchers):
         fut = self._executor.submit(_do_get_groups)
         return FileFutureResult(fut)
 
+    def heartbeat(self):
+        for group_id in self._joined_groups:
+            safe_group_id = self._make_filesystem_safe(group_id)
+            group_dir = os.path.join(self._group_dir, safe_group_id)
+            member_path = os.path.join(group_dir, "%s.raw" %
+                                       self._safe_member_id)
+
+            @_lock_me(self._driver_lock)
+            def _do_heartbeat():
+                try:
+                    os.utime(member_path, None)
+                except EnvironmentError as err:
+                    if err.errno != errno.ENOENT:
+                        raise
+            _do_heartbeat()
+        return self._timeout
+
     @staticmethod
     def watch_elected_as_leader(group_id, callback):
         raise tooz.NotImplemented