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Diffstat (limited to 'lib/spack/docs/configuration.rst')
| -rw-r--r-- | lib/spack/docs/configuration.rst | 83 |
1 files changed, 59 insertions, 24 deletions
diff --git a/lib/spack/docs/configuration.rst b/lib/spack/docs/configuration.rst index 6de823c845..f4d3a65653 100644 --- a/lib/spack/docs/configuration.rst +++ b/lib/spack/docs/configuration.rst @@ -132,6 +132,65 @@ The ``buildable`` does not need to be paired with external packages. It could also be used alone to forbid packages that may be buggy or otherwise undesirable. +.. _system-packages: + +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +False Paths for System Packages +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Sometimes, the externally-installed package one wishes to use with +Spack comes with the Operating System and is installed in a standard +place --- ``/usr``, for example. Many other packages are there as +well. If Spack adds it to build paths, then some packages might +pick up dependencies from ``/usr`` than the intended Spack version. + +In order to avoid this problem, it is advisable to specify a fake path +in ``packages.yaml``, thereby preventing Spack from adding the real +path to compiler command lines. This will work becuase compilers +normally search standard system paths, even if they are not on the +command line. For example: + +.. code-block:: yaml + + packages: + # Recommended for security reasons + # Do not install OpenSSL as non-root user. + openssl: + paths: + openssl@system: /false/path + version: [system] + buildable: False + + +^^^^^^^^^^^^^^^^^^^^^^^^^^ +Extracting System Packages +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In some cases, using false paths for system packages will not work. +Some builds need to run binaries out of their dependencies, not just +access their libraries: the build needs to know the real location of +the system package. + +In this case, one can create a Spack-like single-package tree by +creating symlinks to the files related to just that package. +Depending on the OS, it is possible to obtain a list of the files in a +single OS-installed package. For example, on RedHat / Fedora: + +.. code-block:: console + + $ repoquery --list openssl-devel + ... + /usr/lib/libcrypto.so + /usr/lib/libssl.so + /usr/lib/pkgconfig/libcrypto.pc + /usr/lib/pkgconfig/libssl.pc + /usr/lib/pkgconfig/openssl.pc + ... + +Spack currently does not provide an automated way to create a symlink +tree to these files. + + .. _concretization-preferences: -------------------------- @@ -190,27 +249,3 @@ The syntax for the ``provider`` section differs slightly from other concretization rules. A provider lists a value that packages may ``depend_on`` (e.g, mpi) and a list of rules for fulfilling that dependency. - ---------- -Profiling ---------- - -Spack has some limited built-in support for profiling, and can report -statistics using standard Python timing tools. To use this feature, -supply ``-p`` to Spack on the command line, before any subcommands. - -.. _spack-p: - -^^^^^^^^^^^^^^^^^^^ -``spack --profile`` -^^^^^^^^^^^^^^^^^^^ - -``spack --profile`` output looks like this: - -.. command-output:: spack --profile graph --deptype=nobuild dyninst - :ellipsis: 25 - -The bottom of the output shows the top most time consuming functions, -slowest on top. The profiling support is from Python's built-in tool, -`cProfile -<https://docs.python.org/2/library/profile.html#module-cProfile>`_. |