From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Sixt Subject: Re: [PATCH v2] fetch-pack: optionally save packs to disk Date: Fri, 12 Jun 2015 08:22:50 +0200 Message-ID: <557A7ABA.2000404@kdbg.org> References: <1434049168-10613-1-git-send-email-augie@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: Stefan Beller , Junio C Hamano To: Augie Fackler , git@vger.kernel.org X-From: git-owner@vger.kernel.org Fri Jun 12 08:23:02 2015 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Z3IMm-0003c6-TT for gcvg-git-2@plane.gmane.org; Fri, 12 Jun 2015 08:23:01 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751044AbbFLGW4 (ORCPT ); Fri, 12 Jun 2015 02:22:56 -0400 Received: from bsmtp8.bon.at ([213.33.87.20]:20942 "EHLO bsmtp.bon.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750808AbbFLGWz (ORCPT ); Fri, 12 Jun 2015 02:22:55 -0400 Received: from dx.site (unknown [93.83.142.38]) by bsmtp.bon.at (Postfix) with ESMTPSA id 3m7Bn80JZRz5tlM; Fri, 12 Jun 2015 08:22:51 +0200 (CEST) Received: from [IPv6:::1] (localhost [IPv6:::1]) by dx.site (Postfix) with ESMTP id 2198C5252; Fri, 12 Jun 2015 08:22:51 +0200 (CEST) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 In-Reply-To: <1434049168-10613-1-git-send-email-augie@google.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Am 11.06.2015 um 20:59 schrieb Augie Fackler: > When developing server software, it's often helpful to save a > potentially-bogus pack for later analysis. This makes that trivial, > instead of painful. When you develop server software, shouldn't you test drive the server via the bare metal protocol anyway? That *is* painful, but unavoidable because you must harden the server against any garbage that a potentially malicous client could throw at it. Restricting yourself to a well-behaved client such as fetch-pack is only half the deal. That said, I do think that fetch-pack could learn a mode that makes it easier to debug the normal behavior of a server (if such a mode is missing currently). What is the problem with the current fetch-pack implementation? Does it remove a bogus packfile after download? Does it abort during download when it detects a broken packfile? Does --keep not do what you need? Instead of your approach (which forks off tee to dump a copy of the packfile), would it not be simpler to add an option --debug-pack (probably not the best name) that skips the cleanup step when a broken packfile is detected and prints the name of the downloaded packfile? > diff --git a/fetch-pack.c b/fetch-pack.c > index a912935..fe6ba58 100644 > --- a/fetch-pack.c > +++ b/fetch-pack.c > @@ -684,7 +684,7 @@ static int get_pack(struct fetch_pack_args *args, > const char *argv[22]; > char keep_arg[256]; > char hdr_arg[256]; > - const char **av, *cmd_name; > + const char **av, *cmd_name, *savepath; > int do_keep = args->keep_pack; > struct child_process cmd = CHILD_PROCESS_INIT; > int ret; > @@ -708,9 +708,8 @@ static int get_pack(struct fetch_pack_args *args, > cmd.argv = argv; > av = argv; > *hdr_arg = 0; > + struct pack_header header; > if (!args->keep_pack && unpack_limit) { > - struct pack_header header; > - > if (read_pack_header(demux.out, &header)) > die("protocol error: bad pack header"); > snprintf(hdr_arg, sizeof(hdr_arg), > @@ -762,7 +761,44 @@ static int get_pack(struct fetch_pack_args *args, > *av++ = "--strict"; > *av++ = NULL; > > - cmd.in = demux.out; > + savepath = getenv("GIT_SAVE_FETCHED_PACK_TO"); > + if (savepath) { > + struct child_process cmd2 = CHILD_PROCESS_INIT; > + const char *argv2[22]; > + int pipefds[2]; > + int e; > + const char **av2; > + cmd2.argv = argv2; > + av2 = argv2; > + *av2++ = "tee"; > + if (*hdr_arg) { > + /* hdr_arg being nonempty means we already read the > + * pack header from demux, so we need to drop a pack > + * header in place for tee to append to, otherwise > + * we'll end up with a broken pack on disk. > + */ /* * Write multi-line comments * like this (/* on its own line) */ > + int fp; > + struct sha1file *s; > + fp = open(savepath, O_CREAT | O_TRUNC | O_WRONLY, 0666); > + s = sha1fd_throughput(fp, savepath, NULL); > + sha1write(s, &header, sizeof(header)); > + sha1flush(s); Are you abusing sha1write() and sha1flush() to write a byte sequence to a file? Is write_in_full() not sufficient? > + close(fp); > + /* -a is supported by both GNU and BSD tee */ > + *av2++ = "-a"; > + } > + *av2++ = savepath; > + *av2++ = NULL; > + cmd2.in = demux.out; > + e = pipe(pipefds); > + if (e != 0) > + die("couldn't make pipe to save pack"); start_command() can create the pipe for you. Just say cmd2.out = -1. > + cmd2.out = pipefds[1]; > + cmd.in = pipefds[0]; > + if (start_command(&cmd2)) > + die("couldn't start tee to save a pack"); When you call start_command(), you must also call finish_command(). start_command() prints an error message for you; you don't have to do that (the start_command() in the context below is a bad example). > + } else > + cmd.in = demux.out; > cmd.git_cmd = 1; > if (start_command(&cmd)) > die("fetch-pack: unable to fork off %s", cmd_name); > diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh > index 58207d8..bf4640d 100755 > --- a/t/t5551-http-fetch-smart.sh > +++ b/t/t5551-http-fetch-smart.sh > @@ -82,11 +82,23 @@ test_expect_success 'fetch changes via http' ' > test_cmp file clone/file > ' > > +test_expect_success 'fetch changes via http and save pack' ' > + echo content >>file && > + git commit -a -m two && > + git push public && > + GIT_SAVE_FETCHED_PACK_TO=saved.pack && > + export GIT_SAVE_FETCHED_PACK_TO && > + (cd clone && git pull) && This can be written as ( cd clone && GIT_SAVE_FETCHED_PACK_TO=../saved.pack git pull ) && without 'export'. > + git index-pack clone/saved.pack > +' > + > cat >exp < GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1 200 > POST /smart/repo.git/git-upload-pack HTTP/1.1 200 > GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1 200 > POST /smart/repo.git/git-upload-pack HTTP/1.1 200 > +GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1 200 > +POST /smart/repo.git/git-upload-pack HTTP/1.1 200 > EOF > test_expect_success 'used upload-pack service' ' > sed -e " > diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh > index bfdaf75..73f9e1c 100755 > --- a/t/t5601-clone.sh > +++ b/t/t5601-clone.sh > @@ -40,6 +40,15 @@ test_expect_success C_LOCALE_OUTPUT 'output from clone' ' > test $(grep Clon output | wc -l) = 1 > ' > > +test_expect_success 'clone allows saving a pack' ' > + rm -fr dst saved.pack && > + GIT_SAVE_FETCHED_PACK_TO=saved.pack && > + export GIT_SAVE_FETCHED_PACK_TO && > + git clone -n "file://$(pwd)/src" dst >output 2>&1 && Same here. > + test -e saved.pack && > + git index-pack saved.pack > +' > + > test_expect_success 'clone does not keep pack' ' > > rm -fr dst && > -- Hannes