[atomic-devel] [fedora-atomic f23] remove Python source files

[Giuseppe Scrivano <gscrivan redhat com>]

Hi,

I was experimenting with reducing the size of the Atomic Host image and
it seems that a lot of space is used by Python source files.

I had to deal differently with the two versions as Python 3 handles
source-less distributions in a different way than Python 2.

Python 2 simply loads the *.pyc file when the *.py file is missing.

Python 3 requires an additional step, as it puts the precompiled version
under the __pycache__ directory, but it expects the file to be one level
upper when the source file is missing:

/foo/__pycache__/test.cpython-34.pyo -> /foo/test.pyc


This patch reduces the used disk space by around 55 MB.

Any comments?

Thanks,
Giuseppe



>From 277e5fcdd6fbc2f3d51589a4065f2026f8becccd Mon Sep 17 00:00:00 2001
From: Giuseppe Scrivano <gscrivan redhat com>
Date: Mon, 30 Nov 2015 13:42:10 +0100
Subject: [PATCH] treecompose-post.sh: delete any .py file

and leave only the precompiled version.

It frees around 55MB of disk space.

Signed-off-by: Giuseppe Scrivano <gscrivan redhat com>
---
 treecompose-post.sh | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/treecompose-post.sh b/treecompose-post.sh
index 73b6573..39f1ba0 100755
--- a/treecompose-post.sh
+++ b/treecompose-post.sh
@@ -8,3 +8,40 @@ find /usr/share/locale -mindepth  1 -maxdepth 1 -type d -not -name "${KEEPLANG}"
 localedef --list-archive | grep -a -v ^"${KEEPLANG}" | xargs localedef --delete-from-archive
 mv -f /usr/lib/locale/locale-archive /usr/lib/locale/locale-archive.tmpl
 build-locale-archive
+
+# Compile all the files.
+find /usr/lib*/python2.* -type d -exec python2 -OO -m compileall -l {} +
+find /usr/lib*/python3.* -type d -exec python3 -OO -m compileall -l {} +
+
+# Here we treat Python 2 and Python 3 differently:
+
+# Python 2
+# *.pyo files are basically *.pyc files, except that when the source
+# file is missing Python will load only the .pyc file:
+find /usr/lib*/python2.* -type f -name "*.pyo" | while read i
+do
+    destination_pyc=$(echo $i | sed -e's|pyo$|pyc|')
+    rm -f $destination_pyc
+    mv $i $destination_pyc
+done
+find /usr/lib*/python2.* -type f -name "*.py" | while read i
+do
+    test -f ${i}c && rm ${i}
+done
+
+# Python 3 instead keeps the cache file under __pycache__, these files
+# won't be loaded if the source file is missing, but: "In order to
+# continue to support source-less distributions though, if the source
+# file is missing, Python will import a lone pyc file if it lives
+# where the source file would have been." (PEP-3147)
+find /usr/lib*/python3.* -type f -name "*.py[co]" | while read i
+do
+    destination_pyc=$(echo $i | sed -e "s|/__pycache__/|/|" -e "s|\.cpython-3[0-9]*\.pyo|.pyc|")
+    rm -f $destination_pyc
+    mv $i $destination_pyc
+done
+find /usr/lib*/python3.* -type d -name "__pycache__" -exec rm -rf {} +
+find /usr/lib*/python3.* -type f -name "*.py" | while read i
+do
+    test -f ${i}c && rm ${i}
+done
-- 
2.5.0