From 55d049c74cd00495ee2ca2683714b3f42229f0b3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Borgstr=C3=B6m?= <jonas@borgstrom.se>
Date: Sat, 10 Sep 2011 17:19:02 +0200
Subject: [PATCH] Added support for archive checkpoints

---
 darc/archive.py  | 45 +++++++++++++++++++++++++++++++++++----------
 darc/archiver.py | 11 ++++++-----
 darc/test.py     |  3 ++-
 3 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/darc/archive.py b/darc/archive.py
index d4c6c0e86..13fe4f26a 100644
--- a/darc/archive.py
+++ b/darc/archive.py
@@ -6,6 +6,7 @@ import os
 import socket
 import stat
 import sys
+import time
 from cStringIO import StringIO
 from xattr import xattr, XATTR_NOFOLLOW
 
@@ -26,7 +27,11 @@ class Archive(object):
     class DoesNotExist(Exception):
         pass
 
-    def __init__(self, store, key, manifest, name=None, cache=None):
+    class AlreadyExists(Exception):
+        pass
+
+
+    def __init__(self, store, key, manifest, name, cache=None, create=False, checkpoint_interval=300):
         self.key = key
         self.store = store
         self.cache = cache
@@ -35,11 +40,23 @@ class Archive(object):
         self.items_ids = []
         self.hard_links = {}
         self.stats = Statistics()
-        if name:
+        self.name = name
+        self.checkpoint_interval = checkpoint_interval
+        if create:
+            if name in manifest.archives:
+                raise self.AlreadyExists
+            self.last_checkpoint = time.time()
+            i = 0
+            while True:
+                self.checkpoint_name = '%s.checkpoint%s' % (name, i and ('.%d' % i) or '')
+                if not self.checkpoint_name in manifest.archives:
+                    break
+                i += 1
+        else:
             try:
                 info = self.manifest.archives[name]
             except KeyError:
-                raise Archive.DoesNotExist
+                raise self.DoesNotExist
             self.load(info['id'])
 
     def load(self, id):
@@ -79,6 +96,10 @@ class Archive(object):
 
     def add_item(self, item):
         self.items.write(msgpack.packb(item))
+        now = time.time()
+        if now - self.last_checkpoint > self.checkpoint_interval:
+            self.last_checkpoint = now
+            self.write_checkpoint()
         if self.items.tell() > ITEMS_BUFFER:
             self.flush_items()
 
@@ -98,9 +119,15 @@ class Archive(object):
         else:
             self.items.write(chunks[-1])
 
-    def save(self, name, cache):
+    def write_checkpoint(self):
+        self.save(self.checkpoint_name)
+        del self.manifest.archives[self.checkpoint_name]
+        self.cache.chunk_decref(self.id)
+
+    def save(self, name=None):
+        name = name or self.name
         if name in self.manifest.archives:
-            raise ValueError('Archive %s already exists' % name)
+            raise self.AlreadyExists(name)
         self.flush_items(flush=True)
         metadata = {
             'version': 1,
@@ -113,11 +140,11 @@ class Archive(object):
         }
         data = msgpack.packb(metadata)
         self.id = self.key.id_hash(data)
-        cache.add_chunk(self.id, data, self.stats)
+        self.cache.add_chunk(self.id, data, self.stats)
         self.manifest.archives[name] = {'id': self.id, 'time': metadata['time']}
         self.manifest.write()
         self.store.commit()
-        cache.commit()
+        self.cache.commit()
 
     def calc_stats(self, cache):
         # This function is a bit evil since it abuses the cache to calculate
@@ -347,7 +374,5 @@ class Archive(object):
     @staticmethod
     def list_archives(store, key, manifest, cache=None):
         for name, info in manifest.archives.items():
-            archive = Archive(store, key, manifest, cache=cache)
-            archive.load(info['id'])
-            yield archive
+            yield Archive(store, key, manifest, name, cache=cache)
 
diff --git a/darc/archiver.py b/darc/archiver.py
index 024fde574..c62923965 100644
--- a/darc/archiver.py
+++ b/darc/archiver.py
@@ -56,11 +56,9 @@ class Archiver(object):
         store = self.open_store(args.archive)
         key = Key(store)
         manifest = Manifest(store, key)
-        if args.archive.archive in manifest.archives:
-            self.print_error('Archive already exists')
-            return self.exit_code
         cache = Cache(store, key, manifest)
-        archive = Archive(store, key, manifest, cache=cache)
+        archive = Archive(store, key, manifest, args.archive.archive, cache=cache,
+                          create=True, checkpoint_interval=args.checkpoint_interval)
         # Add darc cache dir to inode_skip list
         skip_inodes = set()
         try:
@@ -77,7 +75,7 @@ class Archiver(object):
                 pass
         for path in args.paths:
             self._process(archive, cache, args.patterns, skip_inodes, path)
-        archive.save(args.archive.archive, cache)
+        archive.save()
         if args.stats:
             t = datetime.now()
             diff = t - t0
@@ -310,6 +308,9 @@ class Archiver(object):
         subparser.add_argument('-e', '--exclude', dest='patterns',
                                type=ExcludePattern, action='append',
                                help='Include condition')
+        subparser.add_argument('-c', '--checkpoint-interval', dest='checkpoint_interval',
+                               type=int, default=300, metavar='SECONDS',
+                               help='Write checkpointe ever SECONDS seconds (Default: 300)')
         subparser.add_argument('archive', metavar='ARCHIVE',
                                type=location_validator(archive=True),
                                help='Archive to create')
diff --git a/darc/test.py b/darc/test.py
index 7632a370d..38ce48018 100644
--- a/darc/test.py
+++ b/darc/test.py
@@ -115,7 +115,8 @@ class Test(unittest.TestCase):
     def test_corrupted_store(self):
         self.create_src_archive('test')
         self.darc('verify', self.store_path + '::test')
-        fd = open(os.path.join(self.tmpdir, 'store', 'data', '0', '2'), 'r+')
+        name = sorted(os.listdir(os.path.join(self.tmpdir, 'store', 'data', '0')), reverse=True)[0]
+        fd = open(os.path.join(self.tmpdir, 'store', 'data', '0', name), 'r+')
         fd.seek(100)
         fd.write('X')
         fd.close()