Mailman 3 September 2013 - Distutils-SIG

Comments on PEP 426
by Antoine Pitrou 08 Sep '13

08 Sep '13

Hello, Some comments about PEP 426: > The information defined in this PEP is serialised to pydist.json files for some > use cases. These are files containing UTF-8 encoded JSON metadata. Perhaps add that on-disk pydist.json files may/should be generated in printed form with sorted keys, to ease direct inspection by users and developers? > Source labels MUST be unique within each project and MUST NOT match any > defined version for the project. Is there a motivation for the "not matching any defined version"? AFAICT it makes it necessary to have two different representation schemes, e.g. "X.Y.Z" for source labels and "vX.Y.Z" for versions. > For source archive references, an expected hash value may be specified by > including a ``<hash-algorithm>=<expected-hash>`` entry as part of the URL > fragment. Why only source archive references (and not e.g. binary)? > "project_urls": { > "Documentation": "https://distlib.readthedocs.org" > "Home": "https://bitbucket.org/pypa/distlib" > "Repository": "https://bitbucket.org/pypa/distlib/src" > "Tracker": "https://bitbucket.org/pypa/distlib/issues" > } This example lacks commas. > An abbreviation of "metadistribution requires". This is a list of > subdistributions that can easily be installed and used together by > depending on this metadistribution. I don't understand what it means :-) Care to explain and/or clarify the purpose? (for me, "meta-requires" sounds like something that setup.py depends on for its own operation, but that the installed software doesn't need) (edit: I now see this is clarified in Appendix C. The section ordering in the PEP makes it look like "meta_requires" are the primary type of requires, though, while according to that appendix they're a rather exotic use case. Would be nice to spell that out *before* the appendices :-)). > * MAY allow direct references What is a direct reference? > Automated tools MUST NOT allow strict version matching clauses or direct > references in this field - if permitted at all, such clauses should appear > in ``meta_requires`` instead. Why so? [test requires] > Public index servers SHOULD NOT allow strict version matching clauses or > direct references in this field. Again, why? Is it important for public index servers that test dependencies be not pinned? > Note that while these are build dependencies for the distribution being > built, the installation is a *deployment* scenario for the dependencies. But there are no deployment requires, right? :) (or is what "meta requires" are for?) > For example, multiple projects might supply > PostgreSQL bindings for use with SQL Alchemy: each project might declare > that it provides ``sqlalchemy-postgresql-bindings``, allowing other > projects to depend only on having at least one of them installed. But the automated installer wouldn't be able to suggest the various packages providing ``sqlalchemy-postgresql-bindings`` if none is installed, which should IMO discourage such a scheme. > To handle this case in a way that doesn't allow for name hijacking, the > authors of the distribution that first defines the virtual dependency > should > create a project on the public index server with the corresponding name, > and > depend on the specific distribution that should be used if no other > provider > is already installed. This also has the benefit of publishing the default > provider in a way that automated tools will understand. But then the alternatives needn't provide the "virtual dependency". They can just provide the "default provider", which saves the time and hassle of defining a well-known virtual dependency for all similar projects. > A string that indicates that this project is no longer being developed. > The > named project provides a substitute or replacement. How about a project that is no longer being developed but has no direct substitution? :) Can it use an empty string (or null / None perhaps?) > Examples indicating supported operating systems:: > > # Windows only > "supports_environments": ["sys_platform == 'win32'"] Hmm, which syntax is it exactly? In a previous section, you used the following example: > "environment": "sys.platform == 'win32'" (note dot vs. underscore) > "modules": ["chair", "chair.cushions", (...)] The example is a bit intriguing. Is it expected that both "chair" and "chair.cushions" be specified there, or is "chair" sufficient? > When installing from an sdist, source archive or VCS checkout, > installation > tools SHOULD create a binary archive using ``setup.py bdist_wheel`` and > then install binary archive normally (including invocation of any install > hooks). Installation tools SHOULD NOT invoke ``setup.py install`` > directly. Interesting. Is "setup.py install" meant to die, or will it be redefined as "bdist_wheel + install_wheel"? (also, why is this mentioned in the postinstall hooks section, or even in a metadata-related PEP?) > Installation tools SHOULD treat an exception thrown by a preuninstall > hook as an indication the removal of the distribution should be aborted. I hope a "--force" option will be provided by such tools. Failure to uninstall because of buggy uninstall tools is a frustrating experience. > Extras are additional dependencies that enable an optional aspect > of the distribution I am confused. To me, extras look like additional provides, not additional dependencies. I.e. in: "requires": ["ComfyChair[warmup]"] -> requires ``ComfyChair`` and ``SoftCushions`` "warmup" is an additional provide of ComfyChair, and it depends on SoftCushions. > "requires": ["ComfyChair[*]"] > -> requires ``ComfyChair`` and ``SoftCushions``, but will also > pick up any new extras defined in later versions This one confuses me (again :-)). What does "pick up" mean? Accept? Require? > pip install ComfyChair[-,:*:,*] > -> installs the full set of development dependencies, but avoids > installing ComfyChair itself Are all these possibilities ("-", ":*:", "*") useful in real life? > Environment markers > =================== In this section, there still are inconsistencies in the format examples ("sys.platform" vs. "sys_platform"). > * ``platform_python_implementation``: ``platform.python_implementation()`` > * ``implementation_name````: ``sys.implementation.name`` Why two different ways to spell nearly the same thing: >>> platform.python_implementation() 'CPython' >>> sys.implementation.name 'cpython' (also, look at how platform.python_implementation() is implemented :-)) Also, do the ordering operators ("<=", ">=", etc.) operate logically or lexicographically on version values? > Build labels > ------------ > > See PEP 440 for the rationale behind the addition of this field. I can't see anything named "Build label" in PEP 426. Did you mean "source label"? > This version of the metadata specification continues to use ``setup.py`` > and the distutils command syntax to invoke build and test related > operations on a source archive or VCS checkout. I don't really understand how Metadata 2.0 is dependent on the distutils command scheme. Can you elaborate? Regards Antoine.

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Decommissioning last.pypi.python.org
by Noah Kantrowitz 05 Sep '13

05 Sep '13

I am shortly going to delete last.pypi.python.org. We've checked with all versions of pip, this will not cause any user-facing disruptions and --use-mirrors will be converted into a no-op. Individual \w.pypi.python.org domains will remain in accordance with the PEP until they request to be redirected. If you are doing something outside of pip using the autodiscovery protocol, now would be the time to fix it. --Noah

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"Please use a mix of different-case letters and numbers in your password"
by Antoine Pitrou 05 Sep '13

05 Sep '13

Hi, On PyPI: "Please use a mix of different-case letters and numbers in your password" Ok... has anyone decided to play BOFH on this one? Displaying recommendations is fine (and, why not, some kind of entropy meter), enforcing stupid rules like that is not. Regards Antoine, trying to access his PyPI account...

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Password security
by Nick Coghlan 04 Sep '13

04 Sep '13

On 5 September 2013 00:59, Antoine Pitrou <antoine(a)python.org> wrote: > Nick Coghlan <ncoghlan <at> gmail.com> writes: >> >> That's the whole reason the content restrictions turn themselves off >> once the password hits 16 characters: passphrases are easy to >> remember, and generally quite secure. So, no, "it's easy to remember" >> is not an adequate excuse for choosing a poor password for a service >> that has a lot of other people depending on its integrity. > > Then please add helpful guidelines as to how people can choose a safe > and easy to remember password /or passphrase/. Most people aren't password > experts, and the current one-line message isn't useful. It's a complex topic, hence it takes long articles like http://arstechnica.com/information-technology/2013/06/the-secret-to-online-… to do it justice. The *best* answer is for a service to use 2-factor authentication instead of relying entirely on passwords (the "physical object" Donald mentioned earlier), but we don't have the resources to set that up, and certainly can't require it for all PyPI users (since you either need a physical token or a phone capable of running an app like Google Authenticator). Second best is to use a password manager, either to help remember complex manually generated passwords, letting it generate the passwords for you, or a combination of the two. The Ars article linked above goes through some of the available options. Third is to encourage or require people to use better passwords. The third page of the Ars password management article (http://arstechnica.com/information-technology/2013/06/the-secret-to-online-…) gives some example techniques for generating good pass phrases. There's also the XKCD method (https://xkcd.com/936/) and the Scheier method (see towards the end of https://www.schneier.com/blog/archives/2013/06/a_really_good_a.html). A better password metering system than the current binary "allowed/disallowed" would definitely be desirable (see http://arstechnica.com/security/2013/05/its-official-password-strength-mete…), but isn't going to happen in the current PyPI web application. It might be possible after the migration to Warehouse is complete, though. Cheers, Nick. -- Nick Coghlan | ncoghlan(a)gmail.com | Brisbane, Australia

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tox-1.6.1 / detox-0.9.3: some fixes
by holger krekel 04 Sep '13

04 Sep '13

I just pushed tox-1.6.1 to PyPI which fixes a number of issues Also detox-0.9.3, the parallelizing tox runner, is out. tox aims to automate and standardize testing in Python, see docs: http://tox.testrun.org If you want to support tox development other than through contributions or feedback, you may send gifts to my gittip account: https://www.gittip.com/hpk42/ Oh, and a NOTE on Python2.5 support: support for running tox/detox themselves on python2.5 will be dropped anytime now while _creating_ python2.5 environments (through tox.ini) will remain supported still for some time (but not indefinitely). have fun, holger krekel tox 1.6.1 --------------- - fix issue119: {envsitepackagesdir} is now correctly computed and has a better test to prevent regression. - fix issue116: make 1.6 introduced behaviour of changing to a per-env HOME directory during install activities dependent on "--set-home" for now. Should re-establish the old behaviour when no option is given. - fix issue118: correctly have two tests use realpath(). Thanks Barry Warsaw. - fix test runs on environments without a home directory (in this case we use toxinidir as the homedir) - fix issue117: python2.5 fix: don't use ``--insecure`` option because its very existence depends on presence of "ssl". If you want to support python2.5/pip1.3.1 based test environments you need to install ssl and/or use PIP_INSECURE=1 through ``setenv``. section. - fix issue102: change to {toxinidir} when installing dependencies. this allows to use relative path like in "-rrequirements.txt". detox-0.9.3 ----------------------- - fix issue6: quickly make detox work with tox-1.6 again (although not all 1.6 features supported, e.g. --develop does not work) - fix issue3: don't claim a TROVE identifier of "python3" because detox itself depends on eventlet which does not work on py3 yet. (Nevertheless detox will create py3 environments through tox of course) - fix issue1: support python2.5 again (although we might drop it in the future -- it's enough of tox/detox can _create_ and handle py25 environments, they don't neccessarily need to support running themselv on py25)

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PEP453 - Explicit bootstrapping of pip in Python installations
by Donald Stufft 04 Sep '13

04 Sep '13

Abstract ======== This PEP proposes the inclusion of a method for explicitly bootstrapping `pip`_ as the default package manager for Python. It also proposes that the distributions of Python available via Python.org will automatically run this explicit bootstrapping method and a recommendation to third party redistributors of Python to also provide pip by default (in a way reasonable for their distributions). This PEP does *not* propose the inclusion of pip itself in the standard library. Proposal ======== This PEP proposes the inclusion of a ``getpip`` bootstrapping module in Python 3.4, as well as in the upcoming maintenance releases of Python 2.7 and Python 3.3. Rationale ========= Installing a third party package into a freshly installed Python requires first installing the package manager. This requires users ahead of time to know what the package manager is, where to get them from, and how to install them. The effect of this is that these external projects are required to either blindly assume the user already has the package manager installed, needs to duplicate the instructions and tell their users how to install the package manager, or completely forgo the use of dependencies to ease installation concerns for their users. All of the available options have their own drawbacks. If a project simply assumes a user already has the tooling then they get a confusing error message when the installation command doesn't work. Some operating may ease this pain by providing a global hook that looks for commands that don't exist and suggest an OS package they can install to make the command work. If a project chooses to duplicate the installation instructions and tell their users how to install the package manager before telling them how to install their own project then whenever these instructions need updates they need updating by every project that has duplicated them. This will inevitably not happen in every case leaving many different instructions on how to install it many of them broken or less than optimal. These additional instructions might also confuse users who try to install the package manager a second time thinking that it's part of the instructions of installing the project. The problem of stale instructions can be alleviated by referencing `pip's own bootstrapping instructions <http://www.pip-installer.org/en/latest/installing.html>`__, but the user experience involved still isn't good (especially on Windows, where downloading and running a Python script with the default OS configuration is significantly more painful than downloading and running a binary executable or installer). The projects that have decided to forgo dependencies all together are forced to either duplicate the efforts of other projects by inventing their own solutions to problems or are required to simply include the other projects in their own source trees. Both of these options present their own problems either in duplicating maintenance work across the ecosystem or potentially leaving users vulnerable to security issues because the included code or duplicated efforts are not automatically updated when upstream releases a new version. By providing the package manager by default it will be easier for users trying to install these third party packages as well as easier for the people distributing them as they no longer need to pick the lesser evil. This will become more important in the future as the Wheel_ package format does not have a built in "installer" in the form of ``setup.py`` so users wishing to install a Wheel package will need an installer even in the simple case. Reducing the burden of actually installing a third party package should also decrease the pressure to add every useful module to the standard library. This will allow additions to the standard library to focus more on why Python should have a particular tool out of the box instead of needing to use the difficulty in installing a package as justification for inclusion. Explicit Bootstrapping ====================== An additional module called ``getpip`` will be added to the standard library whose purpose is to install pip and any of its dependencies into the appropriate location (most commonly site-packages). It will expose a single callable named ``bootstrap()`` as well as offer direct execution via ``python -m getpip``. Options for installing it such as index server, installation location (``--user``, ``--root``, etc) will also be available to enable different installation schemes. It is believed that users will want the most recent versions available to be installed so that they can take advantage of the new advances in packaging. Since any particular version of Python has a much longer staying power than a version of pip in order to satisfy a user's desire to have the most recent version the bootstrap will contact PyPI, find the latest version, download it, and then install it. This process is security sensitive, difficult to get right, and evolves along with the rest of packaging. Instead of attempting to maintain a "mini pip" for the sole purpose of installing pip the ``getpip`` module will, as an implementation detail, include a private copy of pip which will be used to discover and install pip from PyPI. It is important to stress that this private copy of pip is *only* an implementation detail and it should *not* be relied on or assumed to exist. Not all users will have network access to PyPI whenever they run the bootstrap. In order to ensure that these users will still be able to bootstrap pip the bootstrap will fallback to simply installing the included copy of pip. This presents a balance between giving users the latest version of pip, saving them from needing to immediately upgrade pip after bootstrapping it, and allowing the bootstrap to work offline in situations where users might already have packages downloaded that they wish to install. Updating the Bundled pip ------------------------ In order to keep up with evolutions in packaging as well as providing users who are using the offline installation method with as recent version as possible the ``getpip`` module should be updates to the latest versions of everything it bootstraps. During the preparation for any release of Python, a script, provided as part of this PEP, should be run to update the bundled packages to the latest versions. This means that maintenance releases of the CPython installers will include an updated version of the ``getpip`` bootstrap module. Pre-installation ================ During the installation of Python from Python.org ``python -m getpip`` should be executed. Leaving people using the Windows or OSX installers with a working copy of pip once the installation has completed. The exact method of this is left up to the maintainers of the installers however if the bootstrapping is optional it should be opt out rather than opt in. The Windows and OSX installers distributed by Python.org will automatically attempt to run ``python -m getpip`` by default however the ``make install`` and ``make altinstall`` commands of the source distribution will not. Keeping the pip bootstrapping as a separate step for make based installations should minimize the changes CPython redistributors need to make to their build processes. Avoiding the layer of indirection through make for the getpip invocation also ensures those installing from a custom source build can easily force an offline installation of pip, install it from a private index server, or skip installing pip entirely. Python Virtual Environments =========================== Python 3.3 included a standard library approach to virtual Python environments through the ``venv`` module. Since it's release it has become clear that very few users have been willing to use this feature in part due to the lack of an installer present by default inside of the virtual environment. They have instead opted to continue using the ``virtualenv`` package which *does* include pip installed by default. To make the ``venv`` more useful to users it will be modified to issue the pip bootstrap by default inside of the new environment while creating it. This will allow people the same convenience inside of the virtual environment as this PEP provides outside of it as well as bringing the ``venv`` module closer to feature parity with the external ``virtualenv`` package making it a more suitable replacement. Recommendations for Downstream Distributors =========================================== A common source of Python installations are through downstream distributors such as the various Linux Distributions [#ubuntu]_ [#debian]_ [#fedora]_, OSX package managers [#homebrew]_, or python specific tools [#conda]_. In order to provide a consistent, user friendly experience to all users of Python regardless of how they attained Python this PEP recommends and asks that downstream distributors: * Ensure that whenever Python is installed pip is also installed. * This may take the form of separate with dependencies on each either so that installing the python package installs the pip package and installing the pip package installs the Python package. * Do not remove the bundled copy of pip. * This is required for offline installation of pip into a virtual environment. * This is similar to the existing ``virtualenv`` package for which many downstream distributors have already made exception to the common "debundling" policy. * This does mean that if ``pip`` needs to be updated due to a security issue, so does the bundled version in the ``getpip`` bootstrap module * Migrate build systems to utilize `pip`_ and `Wheel`_ instead of directly using ``setup.py``. * This will ensure that downstream packages can utilize the new formats which will not have a ``setup.py`` easier. * Ensure that all features of this PEP continue to work with any modifications made. * Online installation of the latest version of pip into a global or virtual python environment using ``python -m getpip``. * Offline installation of the bundled version of pip into a global or virtual python environment using ``python -m getpip``. * ``pip install --upgrade pip`` in a global installation should not affect any already created virtual environments. * ``pip install --upgrade pip`` in a virtual environment should not affect the global installation. Policies & Governance ===================== The maintainers of the bundled software and the CPython core team will work together in order to address the needs of both. The bundled software will still remain external to CPython and this PEP does not include CPython subsuming the responsibilities or decisions of the bundled software. This PEP aims to decrease the burden on end users wanting to use third party packages and the decisions inside it are pragmatic ones that represent the trust that the Python community has placed in the authors and maintainers of the bundled software. Backwards Compatibility ----------------------- The public API of the ``getpip`` module itself will fall under the typical backwards compatibility policy of Python for its standard library. The externally developed software that this PEP bundles does not. Security Releases ----------------- Any security update that affects the ``getpip`` module will be shared prior to release with the PSRT. The PSRT will then decide if the issue inside warrants a security release of Python. Appendix: Rejected Proposals ============================ Implicit Bootstrap ------------------ `PEP439`_, the predecessor for this PEP, proposes it's own solution. Its solution involves shipping a fake ``pip`` command that when executed would implicitly bootstrap and install pip if it does not already exist. This has been rejected because it is too "magical". It hides from the end user when exactly the pip command will be installed or that it is being installed at all. It also does not provide any recommendations or considerations towards downstream packagers who wish to manage the globally installed pip through the mechanisms typical for their system. Including pip In the Standard Library ------------------------------------- Similar to this PEP is the proposal of just including pip in the standard library. This would ensure that Python always includes pip and fixes all of the end user facing problems with not having pip present by default. This has been rejected because we've learned through the inclusion and history of ``distutils`` in the standard library that losing the ability to update the packaging tools independently can leave the tooling in a state of constant limbo. Making it unable to ever reasonably evolve in a timeframe that actually affects users as any new features will not be available to the general population for *years*. Allowing the packaging tools to progress separately from the Python release and adoption schedules allows the improvements to be used by *all* members of the Python community and not just those able to live on the bleeding edge of Python releases. .. _Wheel: http://www.python.org/dev/peps/pep-0427/ .. _pip: http://www.pip-installer.org .. _setuptools: https://pypi.python.org/pypi/setuptools .. _PEP439: http://www.python.org/dev/peps/pep-0439/ References ========== .. [#ubuntu] `Ubuntu <http://www.ubuntu.com/>` .. [#debian] `Debian <http://www.debian.org>` .. [#fedora] `Fedora <https://fedoraproject.org/>` .. [#homebrew] `Homebrew <http://brew.sh/>` .. [#conda] `Conda <http://www.continuum.io/blog/conda>` ----------------- Donald Stufft PGP: 0x6E3CBCE93372DCFA // 7C6B 7C5D 5E2B 6356 A926 F04F 6E3C BCE9 3372 DCFA

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Distributable binary with dependencies
by bharath ravi kumar 02 Sep '13

02 Sep '13

Hi, I'm looking to package an application with all its dependencies for deployment on multiple hosts. I'd like to ensure that there is no compilation or setup step before starting the application in production. An nice to have ability would be to isolate base library dependencies per application (like virtualenv does). Ideally, the development -> deployment lifecycle would involve: (a) Build an application archive with all its dependencies baked in (b) Copy archive to a host in production. (c) Unwrap archive (d) Start services. (Note that the build host & production hosts are identical in architecture, OS patch level and python version). Having looked at various tools (e.g. distutils, setup tools, pip + virtualenv, egg, wheel, pyinstaller, etc.) available to address specific aspects/stages of the development lifecycle, I'm undecided on the tool/methodology to adopt in order to comprehensively solve the above problem. Any recommendation in this regard would be very helpful. Thanks for for your time. -Bharath

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How to detect a namespace packages?
by Hartmut Goebel 02 Sep '13

02 Sep '13

Hi, I'm one of the developers of www.pyinstaller.org, a tool for creating stand-alone executables. We need to reliable detect if a package is a namespace package (nspkg). For each namespace, we need to add an empty fake-module into our executable to keep the import mechanism working. This has to work in all versions of Python starting with 2.4. nspkgs set up via a nspkg.pth-file are detected by being in sys.modules, but imp.find_module() files. For nspkgs using __init__.py-files (which use pkg_resources.declare_namespace() or pkgutil.extend_path()) I have no clue how to detect them. I tried to query meta-information using pkgresources, but I did not find a solution. Any help? -- Regards Hartmut Goebel | Hartmut Goebel | h.goebel(a)crazy-compilers.com | | www.crazy-compilers.com | compilers which you thought are impossible |

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PyPI Pull Request
by anatoly techtonik 01 Sep '13

01 Sep '13

Please, merge. https://bitbucket.org/pypa/pypi/pull-request/3/increase-description-field-h… -- anatoly t.

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