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foundationdb: rework python bindings, build system

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FoundationDB uses Python at build time for some code generation.
However, it also has the official python bindings inside the source code
too, and the code for the Python bindings has some of it auto-generated
at compile time.

This made building python packages unattractive: we want to use the
source code generated from the FoundationDB build, but we don't want to
rebuild it. Previously we would override the 'python' input to the
FoundationDB module, but this meant we would do a complete rebuild, as
it was a necessary build time dependency, even though the resulting
generated code itself would not change. Furthermore, FoundationDB
versions < 6.0 don't properly support Python 3 *for the build system*,
though the bindings supported it, so that caused build failures. But the
first effect is the worst: it meant building separate python2 and
python3 packages implied two complete rebuilds of a single FoundationDB
version. This meant rather than 3 FDB builds, we'd do 3*N where N = the
number of major Python versions we support.

Finally, because we did not use pip to generate a wheel that we install
with metadata recorded for the installation, the FoundationDB python
package couldn't be used as an input to other setup.py-based packages:
there would be no recorded metadata in the dist-info folder which would
say this is the foundationdb package. This greatly limits its utility.

To fix all this, we do a few things:

  - Apply some patches to fix the build system with Python 3.x for
    older FoundationDB versions. (This is nice if end-users have
    overridden the global Python version for some reason.)
  - Move python directly into nativeBuildInputs, so it is only a
    build time dependency.
  - Take the python source code from the ./bindings directory and
    tar it up use later after the build is done, so we get to keep
    the generated code. This is the new 'pythonsrc' output from the
    build. This code doesn't change based on whether or not the input
    or resulting package is using Python 2 or 3, it's totally
    deterministic.
  - The build system also patches up the python source code a little,
    so it can be installed directly with setup.py (it needs a little
    stuff that it normally expects the build system to do.)
  - Rework the python package to a separate file that uses
    buildPythonPackage directly. Because the source code is already
    prepared, it needs almost nothing else. Furthermore, this kills
    the override itself for the foundationdb package, meaning rebuilds
    are no longer needed.
  - This package is very simple and just uses foundationdb.pythonsrc
    as its source input. It also ensures a link to libfdb_c.so can
    be found by ctypes (using substituteInPlace)
  - python-packages.nix now just uses callPackage directly.

The net effect of this is, most importantly, that python packages do not
imply a full rebuild of the server source code: building python2 and
python3 packages from a version of FoundationDB now does not need to
override the foundationdb python input, reducing the number of needless
builds. They instead just run setup.py with the given version as input.

The second biggest effect is that wheel metadata is recorded correctly,
meaning dependent-python-packages that want to use the FoundationDB
bindings e.g. from PyPi should now work fine with buildPythonPackage.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
This commit is contained in:
Austin Seipp 2018-11-15 17:03:31 -06:00
parent 32948a6f3d
commit 6054dabc11
3 changed files with 55 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
pkgs/servers/foundationdb/default.nix
View File

@ -1,5 +1,5 @@
{ stdenv49
, lib, fetchurl, fetchFromGitHub
, lib, fetchurl, fetchpatch, fetchFromGitHub
, which, findutils, m4, gawk
, python, openjdk, mono58, libressl
@ -47,8 +47,8 @@ let
inherit rev sha256;
};
nativeBuildInputs = [ gawk which m4 findutils mono58 ];
buildInputs = [ python openjdk libressl boost ];
nativeBuildInputs = [ python openjdk gawk which m4 findutils mono58 ];
buildInputs = [ libressl boost ];
patches =
[ # For 5.2+, we need a slightly adjusted patch to fix all the ldflags
@ -57,10 +57,24 @@ let
then ./ldflags-6.0.patch
else ./ldflags-5.2.patch)
else ./ldflags-5.1.patch)
] ++
]
# for 6.0+, we do NOT need to apply this version fix, since we can specify
# it ourselves. see configurePhase
(lib.optional (!lib.versionAtLeast version "6.0") ./fix-scm-version.patch);
++ (lib.optional (!lib.versionAtLeast version "6.0") ./fix-scm-version.patch)
# Versions less than 6.0 have a busted Python 3 build due to an outdated
# use of 'print'. Also apply an update to the six module with many bugfixes,
# which is in 6.0+ as well
++ (lib.optional (!lib.versionAtLeast version "6.0") (fetchpatch {
name = "update-python-six.patch";
url = "https://github.com/apple/foundationdb/commit/4bd9efc4fc74917bc04b07a84eb065070ea7edb2.patch";
sha256 = "030679lmc86f1wzqqyvxnwjyfrhh54pdql20ab3iifqpp9i5mi85";
}))
++ (lib.optional (!lib.versionAtLeast version "6.0") (fetchpatch {
name = "import-for-python-print.patch";
url = "https://github.com/apple/foundationdb/commit/ded17c6cd667f39699cf663c0e87fe01e996c153.patch";
sha256 = "11y434w68cpk7shs2r22hyrpcrqi8vx02cw7v5x79qxvnmdxv2an";
}))
;
postPatch = ''
# note: this does not do anything for 6.0+
@ -106,7 +120,6 @@ let
installPhase = ''
mkdir -vp $out/{bin,libexec/plugins} $lib/{lib,share/java} $dev/include/foundationdb
mkdir -vp $python/lib/${python.libPrefix}/site-packages
'' + lib.optionalString (!lib.versionAtLeast version "6.0") ''
# we only copy the TLS library on < 6.0, since it's compiled-in otherwise
@ -123,10 +136,15 @@ let
cp -v ./bindings/java/foundationdb-client.jar $lib/share/java/fdb-java.jar
# python
cp LICENSE ./bindings/python
substitute ./bindings/python/setup.py.in ./bindings/python/setup.py \
--replace 'VERSION' "${version}"
rm -f ./bindings/python/setup.py.in
rm -f ./bindings/python/fdb/*.pth # remove useless files
cp -R ./bindings/python/fdb $python/lib/${python.libPrefix}/site-packages/fdb
# symlink a copy of the shared object into place, so that impl.py can load it
ln -sv $lib/lib/libfdb_c.so $python/lib/${python.libPrefix}/site-packages/fdb/libfdb_c.so
rm -f ./bindings/python/*.rst ./bindings/python/*.mk
cp -R ./bindings/python/ tmp-pythonsrc/
tar -zcf $pythonsrc --transform s/tmp-pythonsrc/python-foundationdb/ ./tmp-pythonsrc/
# binaries
for x in fdbbackup fdbcli fdbserver fdbmonitor; do
@ -140,7 +158,7 @@ let
ln -sfv $out/bin/fdbbackup $out/libexec/backup_agent
'';
outputs = [ "out" "lib" "dev" "python" ];
outputs = [ "out" "lib" "dev" "pythonsrc" ];
meta = with stdenv.lib; {
description = "Open source, distributed, transactional key-value store";

24
pkgs/servers/foundationdb/python.nix Normal file
View File

@ -0,0 +1,24 @@
{ buildPythonPackage, lib, foundationdb }:
buildPythonPackage rec {
pname = "foundationdb";
version = foundationdb.version;
src = foundationdb.pythonsrc;
unpackCmd = "tar xf $curSrc";
patchPhase = ''
substituteInPlace ./fdb/impl.py \
--replace libfdb_c.so "${foundationdb.lib}/lib/libfdb_c.so"
'';
doCheck = false;
meta = with lib; {
description = "Python bindings for FoundationDB";
homepage = https://www.foundationdb.org;
license = with licenses; [ asl20 ];
maintainers = with maintainers; [ thoughtpolice ];
};
}

14
pkgs/top-level/python-packages.nix
View File

@ -11052,17 +11052,9 @@ EOF
rfc7464 = callPackage ../development/python-modules/rfc7464 { };
foundationdb51 = (toPythonModule (pkgs.fdbPackages.override {
inherit python;
}).foundationdb51).python;
foundationdb52 = (toPythonModule (pkgs.fdbPackages.override {
inherit python;
}).foundationdb52).python;
foundationdb60 = (toPythonModule (pkgs.fdbPackages.override {
inherit python;
}).foundationdb60).python;
foundationdb51 = callPackage ../servers/foundationdb/python.nix { foundationdb = pkgs.foundationdb51; };
foundationdb52 = callPackage ../servers/foundationdb/python.nix { foundationdb = pkgs.foundationdb52; };
foundationdb60 = callPackage ../servers/foundationdb/python.nix { foundationdb = pkgs.foundationdb60; };
libtorrentRasterbar = (toPythonModule (pkgs.libtorrentRasterbar.override {
inherit python;