Wednesday, February 8, 2017

Non-freeze, single file distribution of your python project

In my job, I often have to share/distribute Python code to others on my development team or to others in sibling development teams.  These folks are technical and I can easily rely on them to have a reasonably contemporary version of Python already installed.  Thus I don't really want to completely freeze my Python project (via cxFreeze, py2app, py2exe, etc.).  Nor do I want to send my coworkers through the 'create a virtualenv, pip install -r, etc.).

I want a middle-ground.  I want to just send them a file, knowing that it contains all the required dependencies and will just run, assuming they have Python in their path.

I've known for a while that if you zip up a directory full of Python files and so long as the root of the zip file contains a __main__.py file and you can directly run the zip file via python {filename.zip}.

What I didn't know is that you can concatenate a text file containing the Python shebang ('#!/usr/bin/env python') and a python zip file and the resulting file is runnable.

#!/usr/bin/env python
PK^C^D^T^@^B^@^H^@nLHJb±gL<94>^A^@^@Ò^B^@^@^K^@^\^@__main__.pyUT    ^@^C¯,<9b>Xö,<9b>Xux^K^@^A^D«<82><90>~^D^T^@^@^@u<92>ÑkÛ0^PÆßýWܲ^GÙÐ$},^EÃÂ(<85><90>ìq ^Tûâ<88>Z<92>9<9d>º<95>±ÿ}';ÎJ`Â^O<96>ôéû~ºÓ
ÈY©1^F<93>9£4@^Q&<81><8e>O^X<88>2#tCrÌ^N0©¸<83>ÛÑw°ÌÕÂ#®Ë¾^A^PÅ >«¼h@^P;c6<8d>"^Âý=^\AB!ej<91>  <9e>g¦ñ<95>Vgé<87>ÌqÏ^RC<8a>9<99>aq^O^O<9f>Cv^U^AþXQi<88>ÛÌ®°Üx<90>µó<98>^Gl­ ´Z^B<81>^E·¾&^B^C<83>ÕÚ§
,g^LÃ=kW^Y$r­â Æ]HÉ^UÝ5AÂ[V^FC$y<80>¢a<82>y^V^U{°(Ô<9b>^XW}¤h<8f>aØ}¦^G>o<96>êu<9c>e?k<8e>,àbºÔ/ýëh´¶^LÇp^A^Ye<8b>LÕBt<85>w£hi¿&(^HÛîä<96>tÿ.^@A>
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I stumbled upon a tool called pex which will automate generating these shebang/zip files.  While I found pex useful, it seems too much for my needs.  So I started cobbling together my own shebang/zip files by hand as I needed them.

Ultimately, wanted to automate this some, so I ended up creating a simple bash script (which I named 'compile.sh') to speed things up.  Here's that script.  Hope you find this useful.

#!/bin/bash
#
# compile.sh

# Creates a self-runnable, single-file deployable for your python project.
# Your python project's main entry point must be in a file named __main__.py.
# It will embed in the deployable every dependency you've pip-installed in
# your virtualenv .env directory.
#
# The deployable still requires that python is installed on the target system.

if [[ ! -d .env/lib/python2.7/site-packages ]]; then
    echo "This script must be run from a virtualenv root."
    exit 1
fi

if [[ ! -f __main__.py ]]; then
    echo "This will only work if you have a __main__.py file."
    exit 1
fi

if [[ -z "$1" ]]; then
    echo "Usage: $(basename $0) {output_filename}"
    exit 1
fi

TMPDIR="$(mktemp -u /tmp/python.compile.XXXXXXX)"
CURDIR="$(pwd)"
TARGET="$1"

# Create payload zip with our code (remove extra junk)
mkdir -p "$TMPDIR/deps"
zip -9 "$TMPDIR/payload.zip" *
zip -d "$TMPDIR/payload.zip" compile.sh
zip -d "$TMPDIR/payload.zip" requirements.txt
zip -d "$TMPDIR/payload.zip" "$TARGET" > /dev/null

# Gather the virtualenv packages and clean them up
cp -R .env/lib/python2.7/site-packages/* "$TMPDIR/deps"
find "$TMPDIR/deps" -iname '*.pyc' -delete
find "$TMPDIR/deps" -ipath '*pip*' -delete
find "$TMPDIR/deps" -ipath '*easy_install*' -delete
find "$TMPDIR/deps" -ipath '*dist-info*' -delete

# Add the virtualenv packages to the payload
cd "$TMPDIR/deps"
zip -9 -r ../payload.zip *
cd "$CURDIR"

# Assemble the payload into a runable
echo '#!/usr/bin/env python' | cat - "$TMPDIR/payload.zip" > "$TARGET"
chmod +x "$TARGET"

# Cleanup
rm -r "$TMPDIR"

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