The previous method simply used the UNIX timestamp of when the binary was
built as its build label.
$ make && ./git-remote-persistent-http -print_label
1469061546
This patch aims to align the label for this binary with the Git version
contained in the GIT-VERSION-FILE. This gives a better sense of the version
of the binary as it can be mapped to a particular revision or release of
Git itself. For example:
$ make && ./git-remote-persistent-http -print_label
2.9.1.275.g75676c8
Discussion of this patch is available on a related thread in the mailing
list surrounding this package called "contrib/persistent-https: update
ldflags syntax for Go 1.7+". The gmane.org link is:
http://article.gmane.org/gmane.comp.version-control.git/299653/
Signed-off-by: Parker Moore <parkrmoore@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Running `make all` in `contrib/persistent-https` results in a
failure on Go 1.7 and above.
Specifically, the error is:
go build -o git-remote-persistent-https \
-ldflags "-X main._BUILD_EMBED_LABEL 1468613136"
# _/Users/parkr/github/git/contrib/persistent-https
/usr/local/Cellar/go/1.7rc1/libexec/pkg/tool/darwin_amd64/link: -X
flag requires argument of the form importpath.name=value
make: *** [git-remote-persistent-https] Error 2
This `name=value` syntax for the -X flag was introduced in Go v1.5
(released Aug 19, 2015):
- release notes: https://golang.org/doc/go1.5#link
- commit: 12795c02f3
In Go v1.7, support for the old syntax was removed:
- release notes: https://tip.golang.org/doc/go1.7#compiler
- commit: 51b624e6a2
Add '=' between the symbol and its value for recent versions of Go,
while leaving it out for older ones.
Signed-off-by: Parker Moore <parkrmoore@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git over HTTPS has a high request startup latency, since the SSL
negotiation can take up to a second. In order to reduce this latency,
connections should be left open to the Git server across requests
(or invocations of the git commandline).
Reduce SSL startup latency by running a daemon job that keeps
connections open to a Git server. The daemon job
(git-remote-persistent-https--proxy) is started on the first request
through the client binary (git-remote-persistent-https) and remains
running for 24 hours after the last request, or until a new daemon
binary is placed in the PATH. The client determines the daemon's
HTTP address by communicating over a UNIX socket with the daemon.
From there, the rest of the Git protocol work is delegated to the
"git-remote-http" binary, with the environment's http_proxy set to
the daemon.
Accessing /pub/scm/linux/kernel/git/torvalds/linux repository hosted
at kernel.googlesource.com with "git ls-remote" over https:// and
persistent-https:// 5 times shows that the first request takes about
the same time (0.193s vs 0.208s---there is a slight set-up cost for
the local proxy); as expected, the other four requests are much
faster (~0.18s vs ~0.08s).
Incidentally, this also has the benefit of HTTP keep-alive working
across Git command invocations. Its common for servers to use a 5
minute keep-alive on an HTTP 1.1 connection. Git-over-HTTP commonly
uses Transfer-Encoding: chunked on replies, so keep-alive will
generally just work, even though a pack stream's length isn't known
in advance. Because the helper is an external process holding that
connection open, we also benefit from being able to reuse an
existing TCP connection to the server. The same "git ls-remote"
test against http:// vs persistent-https:// URL shows that the
former takes ~0.09s while the first request for the latter is about
0.134s with set-up cost, and subsequent requests are ~0.065s,
shaving around one RTT to the server.
Signed-off-by: Colby Ranger <cranger@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
