From: Brian Warner <warner@lothar.com>
Date: Fri, 1 Dec 2006 11:06:11 +0000 (-0700)
Subject: upload: add WriterProxy
X-Git-Tag: tahoe_v0.1.0-0-UNSTABLE~502
X-Git-Url: https://git.rkrishnan.org/architecture.txt?a=commitdiff_plain;h=f87008cf364a3a25c2ba97dcaaa8b9327a8e737d;p=tahoe-lafs%2Ftahoe-lafs.git

upload: add WriterProxy
---

diff --git a/allmydata/test/test_upload.py b/allmydata/test/test_upload.py
index e0f522af..efcbd74e 100644
--- a/allmydata/test/test_upload.py
+++ b/allmydata/test/test_upload.py
@@ -52,6 +52,13 @@ class NextPeer(unittest.TestCase):
                  "good", # 4
                  ]
 
+    def compare_landlords(self, u, c, expected):
+        exp = [(peerid, bucketnum, c.peers[peerid])
+               for peerid, bucketnum in expected]
+        landlords = [(peerid, bucketnum, proxy.remote_bucket)
+                     for peerid, bucketnum, proxy in u.landlords]
+        self.failUnlessEqual(landlords, exp)
+
     def test_0(self):
         c = FakeClient([])
         u = NextPeerUploader(c)
@@ -74,10 +81,9 @@ class NextPeer(unittest.TestCase):
         d = u.start()
         def _check(res):
             self.failUnlessEqual(u.goodness_points, 2)
-            self.failUnlessEqual(u.landlords,
-                                 [(0, 0, c.peers[0]),
-                                  (4, 1, c.peers[4]),
-                                  ])
+            self.compare_landlords(u, c, [(0, 0),
+                                          (4, 1),
+                                          ])
         d.addCallback(_check)
         return d
 
@@ -90,11 +96,10 @@ class NextPeer(unittest.TestCase):
         d = u.start()
         def _check(res):
             self.failUnlessEqual(u.goodness_points, 3)
-            self.failUnlessEqual(u.landlords,
-                                 [(0, 0, c.peers[0]),
-                                  (4, 1, c.peers[4]),
-                                  (0, 2, c.peers[0]),
-                                  ])
+            self.compare_landlords(u, c, [(0, 0),
+                                          (4, 1),
+                                          (0, 2),
+                                          ])
         d.addCallback(_check)
         return d
 
@@ -114,11 +119,10 @@ class NextPeer(unittest.TestCase):
         d = u.start()
         def _check(res):
             self.failUnlessEqual(u.goodness_points, 3)
-            self.failUnlessEqual(u.landlords,
-                                 [(0, 0, c.peers[0]),
-                                  (3, 1, c.peers[3]),
-                                  (0, 2, c.peers[0]),
-                                  ])
+            self.compare_landlords(u, c, [(0, 0),
+                                          (3, 1),
+                                          (0, 2),
+                                          ])
         d.addCallback(_check)
         return d
 
diff --git a/allmydata/upload.py b/allmydata/upload.py
index 6b69ee03..f9f91567 100644
--- a/allmydata/upload.py
+++ b/allmydata/upload.py
@@ -13,6 +13,30 @@ class HaveAllPeersError(Exception):
 class TooFullError(Exception):
     pass
 
+class WriterProxy:
+    # make this look like a writable file
+    def __init__(self, remote_bucket):
+        self.remote_bucket = remote_bucket
+        self.good = True
+
+    def _broken(self, why):
+        self.good = False
+        # do something else here
+        return why
+
+    def write(self, data):
+        d = self.remote_bucket.callRemote("write", data=data)
+        d.addErrback(self._broken)
+
+    def seek(self, offset, whence=0):
+        d = self.remote_bucket.callRemote("seek", offset=offset, whence=whence)
+        d.addErrback(self._broken)
+
+    def close(self):
+        if self._broken:
+            raise SomethingBrokeError()
+        d = self.remote_bucket.callRemote("close")
+        d.addErrback(self._broken)
 
 class Uploader:
     debug = False
@@ -20,6 +44,9 @@ class Uploader:
     def __init__(self, peer):
         self._peer = peer
 
+    def set_encoder(self, encoder):
+        self._encoder = encoder
+
     def set_verifierid(self, vid):
         assert isinstance(vid, str)
         self._verifierid = vid
@@ -33,7 +60,7 @@ class Uploader:
 
 
     def start(self):
-        # who should we upload to?
+        # first step: who should we upload to?
 
         # maybe limit max_peers to 2*len(self.shares), to reduce memory
         # footprint
@@ -71,7 +98,8 @@ class Uploader:
             def _allocate_response(bucket):
                 if self.debug:
                     print " peerid %s will grant us a lease" % peerid
-                self.landlords.append( (peerid, bucket_num, bucket) )
+                writer = WriterProxy(bucket)
+                self.landlords.append( (peerid, bucket_num, writer) )
                 self.goodness_points += 1
                 if self.goodness_points >= self.target_goodness:
                     if self.debug: print " we're done!"