Always run pip installer to get implicit deps

[mal]

Unconditionally executing the contents of this if block results in the installation of wheel (consistent with <= 3.3 images) without over-zealous overhead:

[...] # end of make install output
Successfully installed pip-9.0.1 setuptools-28.8.0
+ wget -O /tmp/get-pip.py https://bootstrap.pypa.io/get-pip.py
Connecting to bootstrap.pypa.io (151.101.0.175:443)
get-pip.py           100% |*******************************|  1558k  0:00:00 ETA
+ python3 /tmp/get-pip.py pip==9.0.1
Requirement already up-to-date: pip==9.0.1 in /usr/local/lib/python3.6/site-packages
Collecting wheel
  Downloading wheel-0.29.0-py2.py3-none-any.whl (66kB)
Installing collected packages: wheel
Successfully installed wheel-0.29.0
+ rm /tmp/get-pip.py
[...]

Fixes #141, #170

[yosifkit]

Seems sane to me

[tianon]

I'm a little bit confused about what this does that just pip3 install --no-cache-dir --upgrade --force-reinstall pip==9.0.1 is not doing (which is invoked later).

@dstufft would you be willing to give us some advice on whether it's sane / smart to always invoke get-pip.py, regardless of whether our Python install already includes a pip3 which we can use for bootstrapping via --force-reinstall? Any (other) suggestions for improvement? 🙏 😇 ❤️ ❤️

[mal]

It installs wheel which is not present in any of the existing > 3.3 images. If there's a better way of achieving the same, all the better 😄

[dstufft]

I'm on my phone but a quick glance suggests the impetus for this change is that get-pip.py installs pip/setuptools/wheel but ensurepip only installs pip/setuptools. Expanding your later command to also include setuptools and wheel should solve this also I think.

I will take a closer look when I get home.

[tianon]

Oh, we also have #170, where folks are suggesting that we need newer setuptools, so perhaps simply keeping setuptools and wheel up-to-date in the same way we handle pip would make sense? 😄

(Definitely appreciate the input ❤️ ❤️ ❤️)

[mal]

Just did a quick PoC of the suggested approach, following along with how pip version management is done.

There's a version difference between the wheel installed by pip's get-pip.py and the wheel installed as a result of version grabbing from pypi: wheel-0.29.0 vs wheel-0.30.0a0. I'm unsure if that's an issue but worth noting.

Happy to update this PR when we know which direction we'd like to take this 😄

[dstufft]

That'll be because pip excludes pre-releases by default.

[tianon]

Ah, get-pip.py includes the following:

    # Add any implicit installations to the end of our args
    if implicit_pip:
        args += ["pip"]
    if implicit_setuptools:
        args += ["setuptools"]
    if implicit_wheel:
        args += ["wheel"]

(which just installs the latest release of each)

Seems roughly sane (and I think the way we fetch the latest pip version in update.sh accounts for that already, and if not, should be fixed and then copied for doing setuptools and wheel also).

[mal]

In that case I think the current way of getting the package versions might need a tweak, because as I pointed out above, right now it happily grabs pre-release versions.

# curl -fsSL 'https://pypi.python.org/pypi/pip/json' | awk -F '"' '$2 == "version" { print $4 }'
9.0.1
# curl -fsSL 'https://pypi.python.org/pypi/setuptools/json' | awk -F '"' '$2 == "version" { print $4 }'
34.3.3
# curl -fsSL 'https://pypi.python.org/pypi/wheel/json' | awk -F '"' '$2 == "version" { print $4 }'
0.30.0a0

A look at the docs claims that it will fetch the stable version by default but that does not appear to be happening:

This retrieves information about the latest stable release

In the meantime, I'll update this PR with the version that grabs pre-releases and we can go forward from there.

[mal]

I'll squash this down once we're happy with it 😉

[mal]

Is it permissable to use tools such as jq when processing the https://pypi.python.org/pypi/wheel/json style URLs, or are we limited to using common system tools?

[tianon]

Yeah, jq is one that's permissible (we use it in other places, so it's safe to assume it being installed). I was thinking of replacing the awk with jq since that'd be more reliable anyhow. 😄

I think the main issue I see is that the alpha is listed as the actual "latest release" for wheel by PyPI, so I'm not sure how we're expected to know that 0.29.0 is what we ought to be consuming unless we implement the PEP for Python version number sorting ourselves. 😞

[dstufft]

Try https://pypi.org/pypi/wheel/json.

[mal]

Aha! Perfect! I'll get a commit going, thanks 😁

[tianon]

You're a hero, @dstufft ❤️ (thanks for all you do! 👍)

[dstufft]

I feel obligated to mention that URL is technically not "production" which mostly just means there's no alerting if it goes down, but that should be fairly rare to get downtime of that URL that actually makes it unavailable.

[tianon]

Yeah, I figured as much when I checked out https://pypi.org (and saw the warning), but it's only going to be used from our update.sh script that's used for updating the version numbers, not during builds, so I'm +1 on using it since it solves our issues. 😄 ❤️ (especially since now we can claim to be guinea pigs helping test pypi.org! 😇)

[mal]

Anything more to do on this one @tianon?

[tianon]

I took the liberty of rebasing this on #187 for you, and added a commit (60d03bd) which both fixes our pip update code on Windows, and applies this same change there. 👍 🤘

[JayH5]

I'm a bit concerned about tracking the setuptools version as it moves very fast which would lead to these images being rebuilt very often. For example, there's already version 35.0.2.

https://github.com/pypa/setuptools/blame/master/CHANGES.rst

[tianon]

Hmm, good point @JayH5. @yosifkit and I took a look at Python's ./configure options, and we're considering using --without-ensurepip to have Python no longer install the embedded pip at all, and just use get-pip.py unilaterally, which means we can even move the get-pip.py into a separate layer and get even better cache (especially for minor pip bumps). 😅

(Then, since we'll be using get-pip.py unconditionally, we'll always get setuptools and wheel, and they'll be the "latest release at the time of our installation of pip", which also solves the problem of "when do we bump them?" -- they'll be naturally bumped any time Python, pip, or our base image are. 👍)

[tianon]

(Which ironically enough is basically exactly what @mal suggested originally -- sorry @mal 🙈 ❤️ ❤️)