From 28a9c9b900ef1ae7a396b5aa165619dc6a693ade Mon Sep 17 00:00:00 2001
From: Jarrod Johnson <jbjohnso@us.ibm.com>
Date: Wed, 12 Mar 2014 17:12:01 -0400
Subject: [PATCH] Attempt to read in recent state/data from log

The attempt seems to not work right at the moment, but it seems to be in the
right direction and also does grab terminal state.
---
 confluent/consoleserver.py | 18 ++++++++++++----
 confluent/log.py           | 42 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/confluent/consoleserver.py b/confluent/consoleserver.py
index 4eb92579..b4140219 100644
--- a/confluent/consoleserver.py
+++ b/confluent/consoleserver.py
@@ -24,10 +24,17 @@ class _ConsoleHandler(object):
         self.node = node
         self.logger = log.Logger(node, tenant=configmanager.tenant)
         self.buffer = bytearray()
-        self._connect()
-        self.users = {}
+        (text, termstate) = self.logger.read_recent_text(8192)
+        self.buffer += text
         self.appmodedetected = False
         self.shiftin = None
+        if termstate & 1:
+            self.appmodedetected = True
+        if termstate & 2:
+            self.shiftin = '0'
+        self._connect()
+        self.users = {}
+
 
     def _connect(self):
         self._console = plugin.handle_path(
@@ -159,6 +166,10 @@ class _ConsoleHandler(object):
         self._console.write(data)
 
 
+def connect_node(node, configmanager):
+    consk = (node, configmanager.tenant)
+    if consk not in _handled_consoles:
+        _handled_consoles[consk] = _ConsoleHandler(node, configmanager)
 #this represents some api view of a console handler.  This handles things like
 #holding the caller specific queue data, for example, when http api should be
 #sending data, but there is no outstanding POST request to hold it,
@@ -178,8 +189,7 @@ class ConsoleSession(object):
         consk = (node, self.tenant)
         self.ckey = consk
         self.username = username
-        if consk not in _handled_consoles:
-            _handled_consoles[consk] = _ConsoleHandler(node, configmanager)
+        connect_node(node, configmanager)
         _handled_consoles[consk].attachuser(username)
         self._evt = threading.Event()
         self.node = node
diff --git a/confluent/log.py b/confluent/log.py
index a2c7a6f9..1601f683 100644
--- a/confluent/log.py
+++ b/confluent/log.py
@@ -48,6 +48,7 @@
 import collections
 import confluent.config.configmanager as configuration
 import eventlet
+import fcntl
 import os
 import struct
 import time
@@ -116,6 +117,7 @@ class Logger(object):
             elif not self.isconsole:
                 textdate = time.strftime(
                     '%b %d %H:%M:%S ', time.localtime(tstamp))
+            fcntl.flock(self.textfile, fcntl.LOCK_EX)
             offset = self.textfile.tell() + len(textdate)
             datalen = len(data)
             eventaux = entry[4]
@@ -132,13 +134,53 @@ class Logger(object):
             else:
                 textrecord = textdate + data + '\n'
             self.textfile.write(textrecord)
+            fcntl.flock(self.textfile, fcntl.LOCK_UN)
+            fcntl.flock(self.binfile, fcntl.LOCK_EX)
             self.binfile.write(binrecord)
+            fcntl.flock(self.binfile, fcntl.LOCK_UN)
         self.textfile.flush()
         self.binfile.flush()
         if self.closer is None:
             self.closer = eventlet.spawn_after(15, self.closelog)
         self.writer = None
 
+    def read_recent_text(self, size):
+        try:
+            textfile = open(self.textpath, mode='r')
+            binfile = open(self.binpath, mode='r')
+        except IOError:
+            return ('', 0)
+        fcntl.flock(binfile, fcntl.LOCK_SH)
+        binfile.seek(0, 2)
+        binidx = binfile.tell() - 16
+        currsize = 0
+        offsets = collections.deque()
+        termstate = 0
+        while binidx > 0 and currsize < size:
+            binfile.seek(binidx, 0)
+            binidx -= 16
+            recbytes = binfile.read(16)
+            (_, ltype, offset, datalen, tstamp, evtdata, eventaux, _) = \
+                struct.unpack(">BBIHIBBH", recbytes)
+            binrecord = struct.pack(">BBIHIBBH",
+                    16, ltype, offset, datalen, tstamp, evtdata, eventaux, 0)
+            if ltype != 2:
+                continue
+            currsize += datalen
+            offsets.append((offset, datalen))
+            termstate = termstate | eventaux
+        fcntl.flock(binfile, fcntl.LOCK_UN)
+        binfile.close()
+        textdata = ''
+        fcntl.flock(textfile, fcntl.LOCK_SH)
+        while offsets:
+            (offset, len) = offsets.popleft()
+            textfile.seek(offset, 0)
+            textdata += textfile.read(len)
+        fcntl.flock(textfile, fcntl.LOCK_UN)
+        textfile.close()
+        return (textdata, termstate)
+
     def log(self, logdata=None, ltype=None, event=0, eventdata=None):
         if type(logdata) not in (str, unicode, dict):
             raise Exception("Unsupported logdata")