Mercurial > hg
view tests/test-largefiles-small-disk.t @ 37048:fc5e261915b9
wireproto: require POST for all HTTPv2 requests
Wire protocol version 1 transfers argument data via request
headers by default. This has historically caused problems because
servers institute limits on the length of individual HTTP headers
as well as the total size of all request headers. Mercurial servers
can advertise the maximum length of an individual header. But
there's no guarantee any intermediate HTTP agents will accept
headers up to that length.
In the existing wire protocol, server operators typically also
key off the HTTP request method to implement authentication.
For example, GET requests translate to read-only requests and
can be allowed. But read-write commands must use POST and require
authentication. This has typically worked because the only wire
protocol commands that use POST modify the repo (e.g. the
"unbundle" command).
There is an experimental feature to enable clients to transmit
argument data via POST request bodies. This is technically a
better and more robust solution. But we can't enable it by default
because of servers assuming POST means write access.
In version 2 of the wire protocol, the permissions of a request
are encoded in the URL. And with it being a new protocol in a new
URL space, we're not constrained by backwards compatibility
requirements.
This commit adopts the technically superior mechanism of using
HTTP request bodies to send argument data by requiring POST for
all commands. Strictly speaking, it may be possible to send
request bodies on GET requests. But my experience is that not all
HTTP stacks support this. POST pretty much always works. Using POST
for read-only operations does sacrifice some RESTful design
purity. But this API cares about practicality, not about being
in Roy T. Fielding's REST ivory tower.
There's a chance we may relax this restriction in the future. But
for now, I want to see how far we can get with a POST only API.
Differential Revision: https://phab.mercurial-scm.org/D2837
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 13 Mar 2018 11:57:43 -0700 |
parents | a42817fede27 |
children | f4e84dfc06fd |
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Test how largefiles abort in case the disk runs full $ cat > criple.py <<EOF > from __future__ import absolute_import > import errno > import os > import shutil > from mercurial import util > # > # this makes the original largefiles code abort: > _origcopyfileobj = shutil.copyfileobj > def copyfileobj(fsrc, fdst, length=16*1024): > # allow journal files (used by transaction) to be written > if b'journal.' in fdst.name: > return _origcopyfileobj(fsrc, fdst, length) > fdst.write(fsrc.read(4)) > raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC)) > shutil.copyfileobj = copyfileobj > # > # this makes the rewritten code abort: > def filechunkiter(f, size=131072, limit=None): > yield f.read(4) > raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC)) > util.filechunkiter = filechunkiter > # > def oslink(src, dest): > raise OSError("no hardlinks, try copying instead") > util.oslink = oslink > EOF $ echo "[extensions]" >> $HGRCPATH $ echo "largefiles =" >> $HGRCPATH $ hg init alice $ cd alice $ echo "this is a very big file" > big $ hg add --large big $ hg commit --config extensions.criple=$TESTTMP/criple.py -m big abort: No space left on device [255] The largefile is not created in .hg/largefiles: $ ls .hg/largefiles dirstate The user cache is not even created: >>> import os; os.path.exists("$HOME/.cache/largefiles/") False Make the commit with space on the device: $ hg commit -m big Now make a clone with a full disk, and make sure lfutil.link function makes copies instead of hardlinks: $ cd .. $ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob requesting all changes adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files new changesets 390cf214e9ac updating to branch default getting changed largefiles abort: No space left on device [255] The largefile is not created in .hg/largefiles: $ ls bob/.hg/largefiles dirstate