[Group.of.nepali.translators] [Bug 1625667] Re: Trusty: apt does not try next mirror if index file download fails with mirror:// source
** No longer affects: apt (Ubuntu Xenial) ** Changed in: apt (Ubuntu) Status: Invalid => Fix Released ** Changed in: apt (Ubuntu) Importance: Undecided => Medium -- You received this bug notification because you are a member of नेपाली भाषा समायोजकहरुको समूह, which is subscribed to Xenial. Matching subscriptions: Ubuntu 16.04 Bugs https://bugs.launchpad.net/bugs/1625667 Title: Trusty: apt does not try next mirror if index file download fails with mirror:// source Status in apt package in Ubuntu: Fix Released Status in apt source package in Trusty: Fix Committed Bug description: [SRU justification] This fix is needed to allow correct archive mirroring functionality. [Impact] Without this fix, apt-get update and other apt commands requiring Package file access may fail when there are remote transient errors due to archive availability. [Fix] Use std::npos instead of 0 to test presence of "Translation" in ShortDesc. [Test Case] 1) Setup three containers (archive1, archive2, archive3) with a reprepro configuration mirroring the ubuntu restricted archive (to save on space and time to replicate). 2) Add an apache webserver serving the reprepro archive over http on each container 3) Add the following mirrors.txt file to one of the webserver (archive1): $ cat /var/www/html/mirrors.txt http://archive1/ubuntu/ http://archive2/ubuntu/ http://archive3/ubuntu/ 4) Add a client container. Add the IP adresses of the archive[1-3] containers to /etc/hosts. Alias the archive1 address to archive.ubuntu.com similar to the following : $ cat /etc/hosts 127.0.0.1 localhost 10.0.4.182 archive1mirrors.ubuntu.com 10.0.4.127 archive2 10.0.4.193 archive3 5) Add the following line to the /etc/apt/sources.list, commenting all other entries : $ cat /etc/apt/sources.list #deb http://archive.ubuntu.com/ubuntu trusty main #deb http://archive.ubuntu.com/ubuntu trusty-updates main #deb http://archive.ubuntu.com/ubuntu trusty universe #deb http://archive.ubuntu.com/ubuntu trusty-updates universe deb mirror://mirrors.ubuntu.com/mirrors.txt trusty restricted 6) Run $ apt-get -oDebug::Acquire::mirror=true update The log should display for the Packages file : MirrorMethod::Fetch() Failure to get http://10.0.4.193/ubuntu//dists/trusty/restricted/binary-amd64/Packages Err http://10.0.4.193/ubuntu/ trusty/restricted amd64 Packages With the fix you will see : MirrorMethod::Fetch() Failure to get http://10.0.4.193/ubuntu//dists/trusty/restricted/binary-amd64/Packages.gz TryNextMirror: http://10.0.4.127/ubuntu//dists/trusty/restricted/binary-amd64/Packages.gz [Regression] None expected. Worse that can happen is a retry when none was done previously. [Original description of the problem] When using the mirror://mirrors.ubuntu.com/mirrors.txt functionality on Trusty, if the download of the index file fails, apt will not retry on another archive listed in mirrors.txt and will fail. Running the following on Trusty leads to the following result : sudo apt-get update -qq W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-security/universe/binary-amd64/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-security/main/binary-i386/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-security/restricted/binary-i386/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-security/universe/binary-i386/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-updates/main/binary-amd64/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-updates/restricted/binary-amd64/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-updates/universe/binary-amd64/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-updates/main/binary-i386/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-updates/restricted/binary-i386/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] W: Failed to fetch mirror://mirrors.ubuntu.com/mirrors.txt/dists/trusty-updates/universe/binary-i386/Packages 404 Not Found [Mirror: http://ftp.availo.se/ubuntu/] E: Some index files failed to download. They have been ignored, or old ones used instead. The same configuration works correctly on Xenial To manage notifications about this bug go to: htt
[Group.of.nepali.translators] [Bug 1625667] Re: Trusty: apt does not try next mirror if index file download fails with mirror:// source
Julian,
first of all, you are right, I did mix up the series, I'll fix that.
Now, Michael Vogt (mvo), Debian's APT main developer is currently
reviewing the one line fix that solves this issue.
I have a reproducer and was able to identify the root cause and prepare
a fix.
The source of the problem is the following :
string msg = "\nIndex-File: true";
// FIXME: this really should use "IndexTarget::IsOptional()" but that
//seems to be difficult without breaking ABI
if (ShortDesc().find("Translation") != 0)
As outlined in the FIXME, IndexTarget::IsOptional() should be used, and
that is what started to happen with Wily. The code now reads :
if(Target.IsOptional)
msg += "\nFail-Ignore: true";
Here is the complete explanation as provided to MVO :
"When the Queue responsible for fetching the Package file runs, it builds the
Custom600 header with the following method :
> // AcqIndex::Custom600Headers - Insert custom request headers
> /*{{{*/
> // -
>
> /* The only header we use is the last-modified header. */
>
> string pkgAcqIndex::Custom600Headers()
>
> {
>
>string Final = _config->FindDir("Dir::State::lists");
>
>Final += URItoFileName(RealURI);
>
>if (_config->FindB("Acquire::GzipIndexes",false))
>
> Final += ".gz";
>
>
>
>string msg = "\nIndex-File: true";
>
>// FIXME: this really should use "IndexTarget::IsOptional()" but that
>
>//seems to be difficult without breaking ABI
>
>if (ShortDesc().find("Translation") != 0)
>
> msg += "\nFail-Ignore: true";
>
>struct stat Buf;
>
>if (stat(Final.c_str(),&Buf) == 0)
>
> msg += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime);
>
>
>
>return msg;
>
The custom header is set with "Fail-Ignore: true" in the case of a Translation
file. This was true until Wily when the code got refactored to use
"IndexTarget::IsOptional" as mentionned in the FIXME.
As far as I can tell, the issue here is that this is wrong :
if (ShortDesc().find("Translation") != 0)
when string::find() does not find the string, it returns string::npos so this
test is always true. This means that when Packages is downloaded, Fail-Ignore:
is also set to true, which means that TryNextMirror() will not retry.
In MirrorMethod::Failed() :
>if (!Queue->FailIgnore && TryNextMirror())
>
> return;
>
Changing the test in pkgAcqIndex::Custom600Headers() to be :
if (ShortDesc().find("Translation") != string::npos)
Seems to fix the issue quite nicely. From what I can tell, this is the only
place where I found that test on 0. Other places do test with string::npos.
"
As soon as MVO is ok with this, I will SRU the modification and upload
the fix.
Kind regards,
...Louis
** Changed in: apt (Ubuntu Trusty)
Status: Invalid => In Progress
** Changed in: apt (Ubuntu Xenial)
Status: In Progress => Invalid
** Changed in: apt (Ubuntu Trusty)
Importance: Undecided => Medium
** Changed in: apt (Ubuntu Xenial)
Importance: Medium => Undecided
** Changed in: apt (Ubuntu Trusty)
Assignee: (unassigned) => Louis Bouchard (louis-bouchard)
** Changed in: apt (Ubuntu Xenial)
Assignee: Louis Bouchard (louis-bouchard) => (unass
