chg only supports 'hg serve' when the options to the serve command
follow the 'hg serve'. For example, 'hg -R <repo> serve ..' is unsupported.
This leads to issues with chg running for the following tests:
- test-bundle2-exchange.t
- test-clone-uncompressed.t
- test-hgweb-csp.t
- test-http-bad-server.t
- test-http-bundle1.t
- test-http-protocol.t
- test-http.t
There was an effort made earlier to fix this issue for chg and the tests were
fixed to confirm to the compatible pattern. But the new tests did not take care
of the same and hence, fail. Hopefully, there will be continuous build setup
for chg after all tests are made compatible with chg so that we can avoid such
issues.
Test Plan:
Ran the aforementioned tests with and without '--chg' option.
Differential Revision: https://phab.mercurial-scm.org/D946
This patch replaces hardcoded 127.0.0.1 with $LOCALIP in all tests.
Till now, the IPv6 series should make tests pass on common IPv6 systems
where the local device has the address "::1" and the hostname "localhost"
resolves to "::1".
GNU grep, when emitting a matching line that doesn't have a terminating
newline, will add an extra newline. Solaris grep passes the original line
through without the newline. This causes differences in test output when
looking at the last line of the output of get-with-headers.py, which
doesn't usually emit (and certainly doesn't guarantee) a terminating
newline.
Both grep implementations succeed in matching the requested pattern,
though, so rely on specifying the full pattern on grep's commandline
instead of expecting it in the output, and send the output to /dev/null.
With this commit, the HTTP transport now parses the X-HgProto-<N>
header to determine what media type and compression engine to use for
responses. So far, we only compress responses that are already being
compressed with zlib today (stream response types to specific
commands). We can expand things to cover additional response types
later.
The practical side-effect of this commit is that non-zlib compression
engines will be used if both ends support them. This means if both
ends have zstd support, zstd - not zlib - will be used to compress
data!
When cloning the mozilla-unified repository between a local HTTP
server and client, the benefits of non-zlib compression are quite
noticeable:
engine server CPU (s) client CPU (s) bundle size
zlib (l=6) 174.1 283.2 1,148,547,026
zstd (l=1) 99.2 267.3 1,127,513,841
zstd (l=3) 103.1 266.9 1,018,861,363
zstd (l=7) 128.3 269.7 919,190,278
zstd (l=10) 162.0 - 894,547,179
none 95.3 277.2 4,097,566,064
The default zstd compression level is 3. So if you deploy zstd
capable Mercurial to your clients and servers and CPU time on
your server is dominated by "getbundle" requests (clients cloning
and pulling) - and my experience at Mozilla tells me this is often
the case - this commit could drastically reduce your server-side
CPU usage *and* save on bandwidth costs!
Another benefit of this change is that server operators can install
*any* compression engine. While it isn't enabled by default, the
"none" compression engine can now be used to disable wire protocol
compression completely. Previously, commands like "getbundle" always
zlib compressed output, adding considerable overhead to generating
responses. If you are on a high speed network and your server is under
high load, it might be advantageous to trade bandwidth for CPU.
Although, zstd at level 1 doesn't use that much CPU, so I'm not
convinced that disabling compression wholesale is worthwhile. And, my
data seems to indicate a slow down on the client without compression.
I suspect this is due to a lack of buffering resulting in an increase
in socket read() calls and/or the fact we're transferring an extra 3 GB
of data (parsing HTTP chunked transfer and processing extra TCP packets
can add up). This is definitely worth investigating and optimizing. But
since the "none" compressor isn't enabled by default, I'm inclined to
punt on this issue.
This commit introduces tons of tests. Some of these should arguably
have been implemented on previous commits. But it was difficult to
test without the server functionality in place.
This commit introduces support for advertising a server's support for
media types and compression formats in accordance with the spec defined
in internals.wireproto.
The bulk of the new code is a helper function in wireproto.py to
obtain a prioritized list of compression engines available to the
wire protocol. While not utilized yet, we implement support
for obtaining the list of compression engines advertised by the
client.
The upcoming HTTP protocol enhancements are a bit lower-level than
existing tests (most existing tests are command centric). So,
this commit establishes a new test file that will be appropriate
for holding tests around the functionality of the HTTP protocol
itself.
Rounding out this change, `hg debuginstall` now prints compression
engines available to the server.
