view tests/test-clone-uncompressed.t @ 31793:69d8fcf20014

help: document bundle specifications

I softly formalized the concept of a "bundle specification" a while
ago when I was working on clone bundles and stream clone bundles and
wanted a more robust way to define what exactly is in a bundle file.

The concept has existed for a while. Since it is part of the clone
bundles feature and exposed to the user via the "-t" argument to
`hg bundle`, it is something we need to support for the long haul.

After the 4.1 release, I heard a few people comment that they didn't
realize you could generate zstd bundles with `hg bundle`. I'm
partially to blame for not documenting it in bundle's docstring.

Additionally, I added a hacky, experimental feature for controlling
the compression level of bundles in 76104a4899ad. As the commit
message says, I went with a quick and dirty solution out of time
constraints. Furthermore, I wanted to eventually store this
configuration in the "bundlespec" so it could be made more flexible.

Given:

a) bundlespecs are here to stay
b) we don't have great documentation over what they are, despite being
   a user-facing feature
c) the list of available compression engines and their behavior isn't
   exposed
d) we need an extensible place to modify behavior of compression
   engines

I want to move forward with formalizing bundlespecs as a user-facing
feature. This commit does that by introducing a "bundlespec" help
page. Leaning on the just-added compression engine documentation
and API, the topic also conveniently lists available compression
engines and details about them. This makes features like zstd
bundle compression more discoverable. e.g. you can now
`hg help -k zstd` and it lists the "bundlespec" topic.

#require serve

Initialize repository
the status call is to check for issue5130

  $ hg init server
  $ cd server
  $ touch foo
  $ hg -q commit -A -m initial
  >>> for i in range(1024):
  ...     with open(str(i), 'wb') as fh:
  ...         fh.write(str(i))
  $ hg -q commit -A -m 'add a lot of files'
  $ hg st
  $ hg serve -p $HGPORT -d --pid-file=hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ cd ..

Basic clone

  $ hg clone --uncompressed -U http://localhost:$HGPORT clone1
  streaming all changes
  1027 files to transfer, 96.3 KB of data
  transferred 96.3 KB in * seconds (*/sec) (glob)
  searching for changes
  no changes found

Clone with background file closing enabled

  $ hg --debug --config worker.backgroundclose=true --config worker.backgroundcloseminfilecount=1 clone --uncompressed -U http://localhost:$HGPORT clone-background | grep -v adding
  using http://localhost:$HGPORT/
  sending capabilities command
  sending branchmap command
  streaming all changes
  sending stream_out command
  1027 files to transfer, 96.3 KB of data
  starting 4 threads for background file closing
  transferred 96.3 KB in * seconds (*/sec) (glob)
  query 1; heads
  sending batch command
  searching for changes
  all remote heads known locally
  no changes found
  sending getbundle command
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-part: total payload size 58
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-bundle: 1 parts total
  checking for updated bookmarks


Stream clone while repo is changing:

  $ mkdir changing
  $ cd changing

extension for delaying the server process so we reliably can modify the repo
while cloning

  $ cat > delayer.py <<EOF
  > import time
  > from mercurial import extensions, vfs
  > def __call__(orig, self, path, *args, **kwargs):
  >     if path == 'data/f1.i':
  >         time.sleep(2)
  >     return orig(self, path, *args, **kwargs)
  > extensions.wrapfunction(vfs.vfs, '__call__', __call__)
  > EOF

prepare repo with small and big file to cover both code paths in emitrevlogdata

  $ hg init repo
  $ touch repo/f1
  $ $TESTDIR/seq.py 50000 > repo/f2
  $ hg -R repo ci -Aqm "0"
  $ hg -R repo serve -p $HGPORT1 -d --pid-file=hg.pid --config extensions.delayer=delayer.py
  $ cat hg.pid >> $DAEMON_PIDS

clone while modifying the repo between stating file with write lock and
actually serving file content

  $ hg clone -q --uncompressed -U http://localhost:$HGPORT1 clone &
  $ sleep 1
  $ echo >> repo/f1
  $ echo >> repo/f2
  $ hg -R repo ci -m "1"
  $ wait
  $ hg -R clone id
  000000000000