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Mirroring tool that implements the client (mirror) side of PEP 381

Project description

This is a PyPI mirror client according to PEP 381


The following instructions will place the bandersnatch executable in a virtualenv under bandersnatch/bin/bandersnatch.

  • bandersnatch requires >= Python 3.5


This installs the latest stable, released version.

  $ virtualenv --python=python3.5 bandersnatch
  $ cd bandersnatch
  $ bin/pip install -r


This installs the current development version. Use 'hg up ' and run buildout again to choose a specific release.

  $ hg clone
  $ cd bandersnatch
  $ ./


  • Run bandersnatch mirror - it will create an empty configuration file for you in /etc/bandersnatch.conf.
  • Review /etc/bandersnatch.conf and adapt to your needs.
  • Run bandersnatch mirror again. It will populate your mirror with the current status of all PyPI packages - roughly 500GiB (2017-02-12). Expect this to grow substantially over time.
  • Run bandersnatch mirror regularly to update your mirror with any intermediate changes.


Configure your webserver to serve the web/ sub-directory of the mirror. For nginx it should look something like this::

    server {
        server_name <mymirrorname>;
        root <path-to-mirror>/web;
        autoindex on;
        charset utf-8;
  • Note that it is a good idea to have your webserver publish the HTML index files correctly with UTF-8 as the charset. The index pages will work without it but if humans look at the pages the characters will end up looking funny.

  • Make sure that the webserver uses UTF-8 to look up unicode path names. nginx gets this right by default - not sure about others.

Cron jobs

You need to set up one cron job to run the mirror itself.

Here's a sample that you could place in /etc/cron.d/bandersnatch:

    */2 * * * * root bandersnatch mirror |& logger -t bandersnatch[mirror]

This assumes that you have a logger utility installed that will convert the output of the commands to syslog entries.


bandersnatch does not keep much local state in addition to the mirrored data. In general you can just keep rerunning bandersnatch mirror to make it fix errors.

If you delete the state files then the next run will force it to check everything against the master PyPI::

  • delete ./state file and ./todo if they exist in your mirror directory
  • run bandersnatch mirror to get a full sync

Be aware, that full syncs likely take hours depending on PyPIs performance and your network latency and bandwidth.

Operational notes

Case-sensitive filesystem needed

You need to run bandersnatch on a case-sensitive filesystem.

OS X natively does this OK even though the filesystem is not strictly case-sensitive and bandersnatch will work fine when running on OS X. However, tarring a bandersnatch data directory and moving it to, e.g. Linux with a case-sensitive filesystem will lead to inconsistencies. You can fix those by deleting the status files and have bandersnatch run a full check on your data.

Many sub-directories needed

The PyPI has a quite extensive list of packages that we need to maintain in a flat directory. Filesystems with small limits on the number of sub-directories per directory can run into a problem like this::

2013-07-09 16:11:33,331 ERROR: Error syncing package: zweb@802449 OSError: [Errno 31] Too many links: '../pypi/web/simple/zweb'

Specifically we recommend to avoid using ext3. Ext4 and newer does not have the limitation of 32k sub-directories.

Client Compatibility

A bandersnatch static mirror is compatible only to the "static", cacheable parts of PyPI that are needed to support package installation. It does not support more dynamic APIs of PyPI that maybe be used by various clients for other purposes.

An example of an unsupported API is PyPI's XML-RPC interface, which is used when running pip search.


If you have questions or comments, please submit a bug report to

Code of Conduct

Everyone interacting in the bandersnatch project's codebases, issue trackers, chat rooms, and mailing lists is expected to follow the PyPA Code of Conduct.


This client is based on the original pep381client by Martin v. Loewis.

Richard Jones was very patient answering questions at PyCon 2013 and made the protocol more reliable by implementing some PyPI enhancements.

2.2.1 (2018-05-01)

  • Fix missed change for this file :P Fixes #108 - Thanks @cooperlees

2.2.0 (2018-03-28)

  • Allow digest_name to be specified. Fixes #105 - Thanks @ewdurbin !

  • synchronize generated index pages with warehouse - Thanks @ewdurbin !

  • Allow root_uri to be configured - Thanks @ewdurbin ! -- This is how warehouse ( will function

2.1.3 (2018-03-04)

  • Change version from using pkg_resources and set it in package Fixes #98.

  • Add ability to blacklist packages to sync via conf file. Fixes #100.


  • Add saving of JSON metadata grabbed from for syncing Fixes #91 - Thanks @cooperlees -- Can be disabled via config and disabled by default -- bandersnatch symlinks WEB_ROOT/pypi/PKG_NAME/json to WEB_ROOT/json/PKG_NAME


  • Fix proxy usage. A bug in the usage of requests on our XMLRPC client caused this to break. You can now set *_proxy environment variables and get them picked up properly. Fixes #59.

  • Add a dict returned from mirror.synchronize() to show deleted and added files from the last run

  • Fix sorting of releases to use filename and not url

  • Tweak atomic file writes in utils.rewrite() to prefix the temporary file with the 'hidden' filename of the destination adding more support for hashed POSIX filesystems like GlusterFS. - Thanks @cooperlees

2.0.0 (2017-04-05)

  • Move to Python 3. - Thanks @cooperlees !

    Official support starts with Python 3.5 but might get away with using an earlier version of Python 3 (maybe 3.3 or so). However, we plan to start using Python 3.5 features (like asyncio) in the near future, so please be advised that running with an older version of Python 3 is not a supported option for the long term.

  • General update of our dependencies to pave the road for Python 3 support.

  • Remove residual references to the old "statistics" script that isn't in use any longer.

  • Fix return code -- we accidentally returned 1 on successful runs as debugging code was mixed in the main call. Fixes #67.

  • Make the package-specific simple pages human-readable again. Fixes #71.

1.11 (2016-05-18) (2016-05-11)

  • Brownbag release for re-upload. My train's Wifi broke while uploading ending up with a partial file on PyPI. Can your train service do better than mine?

1.10 (2016-05-11)

This is release is massively supported by @dstufft getting bandersnatch back in sync with current packaging ecosystem changes. All clap your hands now, please.

  • Refactor the generation update code to avoid weird update paths due to, well, my personal kink: 'over complication'.

  • Generate the simple index ourselves instead of copying it from PyPI.

  • Support files hosted on a separate domain.

  • Implement PEP 503 normalization rules while also providing support for legacy and very legacy clients.

1.9 (2016-04-21)

  • Fix a long standing, misunderstood bug: a non-deleting mirror would delete packages if they were fully removed from PyPI. Fixes #61

1.8 (2015-03-16)

  • Don't require a X-PyPI-Last-Serial header on file downloads. (Thanks to @dstufft.)

  • Increase our generation to help mirrors recover potential setuptools corruption after some data bug on PyPI.

1.7 (2014-12-14)

  • Fixes #54 by reordering the simple index page and file fetching parts. Thanks @dstufft for the inspiration.

  • Stop syncing serversig files and even start removing them.

1.6.1 (2014-09-24)

  • Create a new generation to enforce a full sync when upgrading. This is required to get the canonical names for all packages.

1.6 (2014-09-24)

  • Implement canonical package directory names to support an upcoming PIP release and other tools. (Thanks to @dstufft)

  • Fix a race condition where workers could get stuck indefinitely waiting for another item in a depleted queue. (Thanks to @hongqn)

1.5 (2014-07-21)

  • Delete broken tests that I forgot to remove.

  • Reduce the officially sanctioned maximum number of connections.

1.4 (2014-04-15)

  • Move towards replacing the XMLRPC API with JSON to make our requests cacheable. Also reduces the amount of requests needed dramatically.

  • Remove apache stats script as this information is no longer being used anyway.

1.3 (2014-02-16)

  • Move to xmlrpc2 to get SSL verification on XML-RPC calls, too. (Fixes #40 and big thanks to @ewdurbin)

1.2 (2014-01-08)

  • Potential performance improvement: use requests' session object to allow HTTP pipelining. Thanks to Wouter Bolsterlee for the recommendation in Fixes #39.

1.1 (2013-11-26)

  • Made code Python 2.6 compatible. Thanks to @ewdurbin for the pull request.

1.0.5 (2013-07-25)

  • Refactor lock acquisition to avoid shadowing exceptions when creating the lockfile vs. acquiring the lock.

  • Move from distribute back to setuptools.

1.0.4 (2013-07-10)

  • Slight brownbag release: the requirements.txt accidentally included a development version of py.test due to my usage of mr.developer.

1.0.3 (2013-07-08)

  • Fix brownbag release with broken 'stable' tag and missing requirements.txt update.

1.0.2 (2013-07-08)

  • Generate the index simple page ourselves: its not signed anyway and helps PyPI caching more aggressively.

  • Add a py.test plugin to actually show a green bar. Hopefully will be integrated into py.test in the near future.

  • Fix dealing with inconsistent todo files: empty files or with an incorrect header will just be deleted and processing resumes at the last known good state.

  • Mark up requirement of Python 2.7 Fixes #19

  • Fix dealing with new CDN cache issues. Thanks to @dstufft for making PyPI support mirrors again.

  • Improve test coverage.

1.0.1 (2013-04-18)

  • Fix packaging: include default config file. (Thanks to Jannis Leidel)

1.0 (2013-04-09)

  • Update pip install documentation to use the a URL for referring to the requirements.txt directly.

  • Adjust buildout and jenkins job to stop fighting over the distribute version to install.

1.0rc6 (2013-04-09)

  • Hopefully fixed updating the stable tag when releasing.

1.0rc5 (2013-04-09)

  • Experiment with zest.releaser integration to automatically generate requirements.txt during release process.

1.0rc4 (2013-04-09)

  • Experiment with zest.releaser integration to automatically generate requirements.txt during release process.

1.0rc3 (2013-04-09)

  • Experiment with zest.releaser integration to automatically generate requirements.txt during release process.

1.0rc2 (2013-04-09)

  • Experiment with zest.releaser integration to automatically generate requirements.txt during release process.

1.0rc1 (2013-04-09)

  • Initial release. Massive rewrite of pep381client.

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