streamclone: support for producing and consuming stream clone bundles
Up to this point, stream clones only existed as a dynamically generated
data format produced and consumed during streaming clones. In order to
support this efficient cloning format with the clone bundles feature, we
need a more formal, on disk representation of the streaming clone data.
This patch introduces a new "bundle" type for streaming clones. Unlike
existing bundles, it does not contain changegroup data. It does,
however, share the same concepts like the 4 byte header which identifies
the type of data that follows and the 2 byte abbreviation for
compression types (of which only "UN" is currently supported).
The new bundle format is essentially the existing stream clone version 1
data format with some headers at the beginning.
Content negotiation at stream clone request time checked for repository
format/requirements compatibility before initiating a stream clone. We
can't do active content negotiation when using clone bundles. So, we put
this set of requirements inside the payload so consumers have a built-in
mechanism for checking compatibility before reading and applying lots of
data. Of course, we will also advertise this requirements set in clone
bundles. But that's for another patch.
We currently don't have a mechanism to produce and consume this new
bundle format. This will be implemented in upcoming patches.
It's worth noting that if a legacy client attempts to `hg unbundle` a
stream clone bundle (with the "HGS1" header), it will abort with:
"unknown bundle version S1," which seems appropriate.
#require no-msys # MSYS will translate web paths as if they were file paths
This is a test of the wire protocol over CGI-based hgweb.
initialize repository
$ hg init test
$ cd test
$ echo a > a
$ hg ci -Ama
adding a
$ cd ..
$ cat >hgweb.cgi <<HGWEB
> #
> # An example CGI script to use hgweb, edit as necessary
> import cgitb
> cgitb.enable()
> from mercurial import demandimport; demandimport.enable()
> from mercurial.hgweb import hgweb
> from mercurial.hgweb import wsgicgi
> application = hgweb("test", "Empty test repository")
> wsgicgi.launch(application)
> HGWEB
$ chmod 755 hgweb.cgi
try hgweb request
$ . "$TESTDIR/cgienv"
$ QUERY_STRING="cmd=changegroup&roots=0000000000000000000000000000000000000000"; export QUERY_STRING
$ python hgweb.cgi >page1 2>&1
$ python "$TESTDIR/md5sum.py" page1
1f424bb22ec05c3c6bc866b6e67efe43 page1
make sure headers are sent even when there is no body
$ QUERY_STRING="cmd=listkeys&namespace=nosuchnamespace" python hgweb.cgi
Status: 200 Script output follows\r (esc)
Content-Type: application/mercurial-0.1\r (esc)
Content-Length: 0\r (esc)
\r (esc)