tests/test-share.t

wireproto: compress data from a generator

Currently, the "getbundle" wire protocol command obtains a generator of
data, converts it to a util.chunkbuffer, then converts it back to a
generator via the protocol's groupchunks() implementation. For the SSH
protocol, groupchunks() simply reads 4kb chunks then write()s the
data to a file descriptor. For the HTTP protocol, groupchunks() reads
32kb chunks, feeds those into a zlib compressor, emits compressed data
as it is available, and that is sent to the WSGI layer, where it is
likely turned into HTTP chunked transfer chunks as is or further
buffered and turned into a larger chunk.

For both the SSH and HTTP protocols, there is inefficiency from using
util.chunkbuffer.

For SSH, emitting consistent 4kb chunks sounds nice. However, the file
descriptor it is writing to is almost certainly buffered. That means
that a Python .write() probably doesn't translate into exactly what is
written to the I/O layer.

For HTTP, we're going through an intermediate layer to zlib compress
data. So all util.chunkbuffer is doing is ensuring that the chunks we
feed into the zlib compressor are of uniform size. This means more CPU
time in Python buffering and emitting chunks in util.chunkbuffer but
fewer function calls to zlib.

This patch introduces and implements a new wire protocol abstract
method: compresschunks(). It is like groupchunks() except it operates
on a generator instead of something with a .read(). The SSH
implementation simply proxies chunks. The HTTP implementation uses
zlib compression.

To avoid duplicate code, the HTTP groupchunks() has been reimplemented
in terms of compresschunks().

To prove this all works, the "getbundle" wire protocol command has been
switched to compresschunks(). This removes the util.chunkbuffer from
that command. Now, data essentially streams straight from the
changegroup emitter to the wire, possibly through a zlib compressor.
Generators all the way, baby.

There were slim to no performance changes on the server as measured
with the mozilla-central repository. This is likely because CPU
time is dominated by reading revlogs, producing the changegroup, and
zlib compressing the output stream. Still, this brings us a little
closer to our ideal of using generators everywhere.

#require killdaemons

  $ echo "[extensions]"      >> $HGRCPATH
  $ echo "share = "          >> $HGRCPATH

prepare repo1

  $ hg init repo1
  $ cd repo1
  $ echo a > a
  $ hg commit -A -m'init'
  adding a

share it

  $ cd ..
  $ hg share repo1 repo2
  updating working directory
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

share shouldn't have a store dir

  $ cd repo2
  $ test -d .hg/store
  [1]

Some sed versions appends newline, some don't, and some just fails

  $ cat .hg/sharedpath; echo
  $TESTTMP/repo1/.hg (glob)

trailing newline on .hg/sharedpath is ok
  $ hg tip -q
  0:d3873e73d99e
  $ echo '' >> .hg/sharedpath
  $ cat .hg/sharedpath
  $TESTTMP/repo1/.hg (glob)
  $ hg tip -q
  0:d3873e73d99e

commit in shared clone

  $ echo a >> a
  $ hg commit -m'change in shared clone'

check original

  $ cd ../repo1
  $ hg log
  changeset:   1:8af4dc49db9e
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     change in shared clone
  
  changeset:   0:d3873e73d99e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     init
  
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat a             # should be two lines of "a"
  a
  a

commit in original

  $ echo b > b
  $ hg commit -A -m'another file'
  adding b

check in shared clone

  $ cd ../repo2
  $ hg log
  changeset:   2:c2e0ac586386
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     another file
  
  changeset:   1:8af4dc49db9e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     change in shared clone
  
  changeset:   0:d3873e73d99e
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     init
  
  $ hg update
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat b             # should exist with one "b"
  b

hg serve shared clone

  $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ get-with-headers.py localhost:$HGPORT 'raw-file/'
  200 Script output follows
  
  
  -rw-r--r-- 4 a
  -rw-r--r-- 2 b
  
  

test unshare command

  $ hg unshare
  $ test -d .hg/store
  $ test -f .hg/sharedpath
  [1]
  $ hg unshare
  abort: this is not a shared repo
  [255]

check that a change does not propagate

  $ echo b >> b
  $ hg commit -m'change in unshared'
  $ cd ../repo1
  $ hg id -r tip
  c2e0ac586386 tip

  $ cd ..


test sharing bookmarks

  $ hg share -B repo1 repo3
  updating working directory
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo1
  $ hg bookmark bm1
  $ hg bookmarks
   * bm1                       2:c2e0ac586386
  $ cd ../repo2
  $ hg book bm2
  $ hg bookmarks
   * bm2                       3:0e6e70d1d5f1
  $ cd ../repo3
  $ hg bookmarks
     bm1                       2:c2e0ac586386
  $ hg book bm3
  $ hg bookmarks
     bm1                       2:c2e0ac586386
   * bm3                       2:c2e0ac586386
  $ cd ../repo1
  $ hg bookmarks
   * bm1                       2:c2e0ac586386
     bm3                       2:c2e0ac586386

test that commits work

  $ echo 'shared bookmarks' > a
  $ hg commit -m 'testing shared bookmarks'
  $ hg bookmarks
   * bm1                       3:b87954705719
     bm3                       2:c2e0ac586386
  $ cd ../repo3
  $ hg bookmarks
     bm1                       3:b87954705719
   * bm3                       2:c2e0ac586386
  $ echo 'more shared bookmarks' > a
  $ hg commit -m 'testing shared bookmarks'
  created new head
  $ hg bookmarks
     bm1                       3:b87954705719
   * bm3                       4:62f4ded848e4
  $ cd ../repo1
  $ hg bookmarks
   * bm1                       3:b87954705719
     bm3                       4:62f4ded848e4
  $ cd ..

test pushing bookmarks works

  $ hg clone repo3 repo4
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo4
  $ hg boo bm4
  $ echo foo > b
  $ hg commit -m 'foo in b'
  $ hg boo
     bm1                       3:b87954705719
     bm3                       4:62f4ded848e4
   * bm4                       5:92793bfc8cad
  $ hg push -B bm4
  pushing to $TESTTMP/repo3 (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  exporting bookmark bm4
  $ cd ../repo1
  $ hg bookmarks
   * bm1                       3:b87954705719
     bm3                       4:62f4ded848e4
     bm4                       5:92793bfc8cad
  $ cd ../repo3
  $ hg bookmarks
     bm1                       3:b87954705719
   * bm3                       4:62f4ded848e4
     bm4                       5:92793bfc8cad
  $ cd ..

test behavior when sharing a shared repo

  $ hg share -B repo3 repo5
  updating working directory
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd repo5
  $ hg book
     bm1                       3:b87954705719
     bm3                       4:62f4ded848e4
     bm4                       5:92793bfc8cad
  $ cd ..

test what happens when an active bookmark is deleted

  $ cd repo1
  $ hg boo -d bm3
  $ hg boo
   * bm1                       3:b87954705719
     bm4                       5:92793bfc8cad
  $ cd ../repo3
  $ hg boo
     bm1                       3:b87954705719
     bm4                       5:92793bfc8cad
  $ cd ..

verify that bookmarks are not written on failed transaction

  $ cat > failpullbookmarks.py << EOF
  > """A small extension that makes bookmark pulls fail, for testing"""
  > from mercurial import extensions, exchange, error
  > def _pullbookmarks(orig, pullop):
  >     orig(pullop)
  >     raise error.HookAbort('forced failure by extension')
  > def extsetup(ui):
  >     extensions.wrapfunction(exchange, '_pullbookmarks', _pullbookmarks)
  > EOF
  $ cd repo4
  $ hg boo
     bm1                       3:b87954705719
     bm3                       4:62f4ded848e4
   * bm4                       5:92793bfc8cad
  $ cd ../repo3
  $ hg boo
     bm1                       3:b87954705719
     bm4                       5:92793bfc8cad
  $ hg --config "extensions.failpullbookmarks=$TESTTMP/failpullbookmarks.py" pull $TESTTMP/repo4
  pulling from $TESTTMP/repo4 (glob)
  searching for changes
  no changes found
  adding remote bookmark bm3
  abort: forced failure by extension
  [255]
  $ hg boo
     bm1                       3:b87954705719
     bm4                       5:92793bfc8cad
  $ hg pull $TESTTMP/repo4
  pulling from $TESTTMP/repo4 (glob)
  searching for changes
  no changes found
  adding remote bookmark bm3
  $ hg boo
     bm1                       3:b87954705719
   * bm3                       4:62f4ded848e4
     bm4                       5:92793bfc8cad
  $ cd ..

verify bookmark behavior after unshare

  $ cd repo3
  $ hg unshare
  $ hg boo
     bm1                       3:b87954705719
   * bm3                       4:62f4ded848e4
     bm4                       5:92793bfc8cad
  $ hg boo -d bm4
  $ hg boo bm5
  $ hg boo
     bm1                       3:b87954705719
     bm3                       4:62f4ded848e4
   * bm5                       4:62f4ded848e4
  $ cd ../repo1
  $ hg boo
   * bm1                       3:b87954705719
     bm3                       4:62f4ded848e4
     bm4                       5:92793bfc8cad
  $ cd ..

Explicitly kill daemons to let the test exit on Windows

  $ killdaemons.py