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

Project description

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This is a PyPI mirror client according to PEP 381 + PEP 503

  • bandersnatch >=4.0 supports Linux, MacOSX + Windows
  • Documentation

bandersnatch maintainers are looking for more help! Please refer to our MAINTAINER documentation to see the roles and responsibilities. We would also ask you read our Mission Statement to ensure it aligns with your thoughts for this project.

  • If interested contact @cooperlees

bandersnatch has it's dependencies kept up to date by!

  • If you'd like to have your dependencies kept up to date in your requirements.txt or setup.cfg, this is the service for you!


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

  • bandersnatch requires >= Python 3.6.1


This will pull latest build. Please use a specific tag if desired.

  • Docker image includes /bandersnatch/src/ to periodically run a bandersnatch mirror
    • Please /bandersnatch/src/ --help for usage
  • With docker, we reccomend bind mounting in a read only bandersnatch.conf
    • Defaults to /conf/bandersnatch.conf
docker pull pypa/bandersnatch
docker run pypa/bandersnatch bandersnatch --help


This installs the latest stable, released version.

python3.6 -m venv bandersnatch
bandersnatch/bin/pip install bandersnatch
bandersnatch/bin/bandersnatch --help


  • 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. Current mirror package size can be seen here:
  • A blacklist or whitelist can be created to cut down your mirror size. You might want to Analyze PyPI downloads to determine which packages to add to your list.
  • 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 {
        listen [::1]:80;
        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 want to force bandersnatch to check everything against the master PyPI:

  • run bandersnatch mirror --force-check to move status files if they exist in your mirror directory in order get a full sync.

Be aware that full syncs likely take hours depending on PyPI's performance and your network latency and bandwidth.

Other Commands

  • bandersnatch delete --help - Allows you to specify package(s) to be removed from your mirror (dangerous)
  • bandersnatch verify --help - Crawls your repo and fixes any missed files + deletes any unowned files found (dangerous)

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.

Windows requires elevated prompt

Bandersnatch makes use of symbolic links. On Windows, this permission is turned off by default for non-admin users. In order to run bandersnatch on Windows either call it from an elevated command prompt (i.e. right-click, run-as Administrator) or give yourself symlink permissions in the group policy editor.

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.

Bandersnatch Mission

The bandersnatch project strives to:

  • Mirror all static objects of the Python Package Index (
  • bandersnatch's main goal is to support the main global index to local syncing only
  • This will allow organizations to have lower latency access to PyPI and save bandwidth on their WAN connections and more importantly the PyPI CDN
  • Custom features and requests may be accepted if they can be of a plugin form
    • e.g. refer to the blacklist and whitelist plugins


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

  • IRC: #bandersnatch on Freenode (You can use webchat if you don't have an IRC client)

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.

Christian Theune for creating and maintaining bandersnatch for many years!

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