An article about software collections

content/articles/016-software-collections.rst

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+====================
+Software collections
+====================
+
+:date: 2014-08-15 20:49
+:tags: scl, deployment
+:category: devop
+:author: Dmitrijs Milajevs
+
+Intro
+=====
+
+.. a couple of sentences introducing the problems software collections are
+.. supposed to solve.
+
+Installing software provided in a software collection
+=====================================================
+
+In a virtual machine::
+
+    vagrant init chef/centos-6.5
+    vagrant ssh
+
+Update the system and enable EPEL::
+
+    sudo yum update
+    sudo yum install http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
+
+Enable Python33 software collection from http://softwarecollections.org::
+
+    sudo yum install https://www.softwarecollections.org/en/scls/rhscl/python33/epel-6-x86_64/download/rhscl-python33-epel-6-x86_64-1-2.noarch.rpm
+
+.. note:: ``rhscl/python33`` versus ``python33`` provied by CentOS.
+
+    CentOS provides a `set of collections`__ that are renamed similarly to the
+    collections listed at softwarecollections.org, but (at least at the moment
+    of writing) with less packages.
+
+    __ http://wiki.centos.org/AdditionalResources/Repositories/SCL
+
+    It is important to install ``rhscl-python33-epel-6-x86_64-1-2.noarch.rpm``
+    instead of ``yum install centos-release-SCL``.
+
+Browse available versions::
+
+    yum list available | grep rhscl
+
+Install a package from a collection::
+
+    sudo yum install python33-numpy
+
+Try it out::
+
+    scl enable python33 bash
+    python -c 'import numpy; print(numpy.__file__)'
+    /opt/rh/python33/root/usr/lib64/python3.3/site-packages/numpy/__init__.py
+    exit
+
+centpkg
+=======
+
+Install `centpkg`__, a tool for compiling packages locally from a ``.spec`` file::
+
+    sudo yum install pyrpkg python-setuptools
+    git clone  https://git.centos.org/git/centpkg.git
+    cd centpkg
+    sudo python setup.py install
+    cd ..
+
+__ https://git.centos.org/summary/centpkg.git
+
+Install build dependencies needed in the future::
+
+    sudo yum install python33-build scl-utils-build
+
+
+Build an already existing package using centpkg: NumPy
+======================================================
+
+.. note:: This is just an example of how RPMS provided by CentOS can be built.
+
+    ``rhscl/python33`` already provides NumPy, there is no need in building it. Maybe
+    only to bump the package version to 1.8.
+
+::
+
+    centpkg clone --anonymous -b c7 python33-numpy
+    cd python33-numpy
+
+    sudo yum-builddep SPECS/numpy.spec
+    centpkg local
+
+A custom package: versiontools
+==============================
+
+Follow this `guide`__.
+
+__ https://access.redhat.com/documentation/en-US/Red_Hat_Developer_Toolset/2/html-single/Software_Collections_Guide/index.html#sect-Extending_the_python27_and_python33_Software_Collections
+
+Another custom package: numexpr
+===============================
+
+.. http://data.gpo.zugaina.org/progress/dev-python/numexpr/numexpr-2.4-r1000.ebuild
+   doesn't look bad :)
+
+.. Can http://pkgs.fedoraproject.org/cgit/python-numexpr.git/tree/python-numexpr.spec?h=f19 be used directly?
+
+Create a custom software collection. Call it `nlp`.
+
+::
+
+  mkdir -p nlp/SOURCES nlp/SPEC
+  cd nlp
+  emacs SPEC/nlp.spec
+
+Define a ``numexpr.spec`` file.
+
+
+.. rpmbuild --define "_topdir \`pwd\`" ...