Package Creation Tutorial

This tutorial will walk you through the steps behind building a simple package installation script. We’ll focus on writing a package for mpileaks, an MPI debugging tool. By creating a package file we’re essentially giving Spack a recipe for how to build a particular piece of software. We’re describing some of the software’s dependencies, where to find the package, what commands and options are used to build the package from source, and more. Once we’ve specified a package’s recipe, we can ask Spack to build that package in many different ways.

This tutorial assumes you have a basic familiarity with some of the Spack commands, and that you have a working version of Spack installed. If not, we suggest looking at Spack’s Getting Started guide. This tutorial also assumes you have at least a beginner’s-level familiarity with Python.

Also note that this document is a tutorial. It can help you get started with packaging, but is not intended to be complete. See Spack’s Packaging Guide for more complete documentation on this topic.

Getting Started

A few things before we get started:

  • We’ll refer to the Spack installation location via the environment variable SPACK_ROOT. You should point SPACK_ROOT at wherever you have Spack installed.

  • Add $SPACK_ROOT/bin to your PATH before you start.

  • Make sure your EDITOR environment variable is set to your preferred text editor.

  • We’ll be writing Python code as part of this tutorial. You can find successive versions of the Python code at https://github.com/spack/spack-tutorial under tutorial/examples.

We will use a separate package repository for the tutorial. Package repositories allow you to separate sets of packages that take precedence over one another. We will use the tutorial repo that ships with Spack to avoid breaking the builtin Spack packages.

$ spack repo add $SPACK_ROOT/var/spack/repos/tutorial/
==> Added repo with namespace 'tutorial'.

Creating the Package File

Spack comes with a handy command to create a new package: spack create. This command is given the location of a package’s source code, downloads the code, and sets up some basic packaging infrastructure for you. The mpileaks source code can be found on GitHub, and here’s what happens when we run spack create on it:

$ spack create https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz
==> This looks like a URL for mpileaks
==> Found 1 version of mpileaks:

  1.0  https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz
==>
==> How many would you like to checksum? (default is 1, q to abort) 1
==> Downloading...
==> Fetching https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz
################################################################################################ 100.0%
==> Checksummed 1 version of mpileaks
==> This package looks like it uses the autotools build system
==> Created template for mpileaks package
==> Created package file: /home/spack/spack/var/spack/repos/tutorial/packages/mpileaks/package.py

Spack should spawn a text editor with this file:

tutorial/examples/0.package.py
# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

# ----------------------------------------------------------------------------
# If you submit this package back to Spack as a pull request,
# please first remove this boilerplate and all FIXME comments.
#
# This is a template package file for Spack.  We've put "FIXME"
# next to all the things you'll want to change. Once you've handled
# them, you can save this file and test your package like this:
#
#     spack install mpileaks
#
# You can edit this file again by typing:
#
#     spack edit mpileaks
#
# See the Spack documentation for more information on packaging.
# ----------------------------------------------------------------------------

from spack import *


class Mpileaks(AutotoolsPackage):
    """FIXME: Put a proper description of your package here."""

    # FIXME: Add a proper url for your package's homepage here.
    homepage = "https://www.example.com"
    url      = "https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz"

    # FIXME: Add a list of GitHub accounts to
    # notify when the package is updated.
    # maintainers = ['github_user1', 'github_user2']

    version('1.0', sha256='2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825')

    # FIXME: Add dependencies if required.
    # depends_on('foo')

    def configure_args(self):
        # FIXME: Add arguments other than --prefix
        # FIXME: If not needed delete this function
        args = []
        return args

Spack has created this file in $SPACK_ROOT/var/spack/repos/tutorial/packages/mpileaks/package.py. Take a moment to look over the file. There are a few placeholders that Spack has created, which we’ll fill in as part of this tutorial:

  • We’ll document some information about this package in the comments.

  • We’ll fill in the dependency list for this package.

  • We’ll fill in some of the configuration arguments needed to build this package.

For the moment, exit your editor and let’s see what happens when we try to build this package:

$ spack install mpileaks
==> Installing mpileaks
==> Searching for binary cache of mpileaks
==> Finding buildcaches in /mirror/build_cache
==> No binary for mpileaks found: installing from source
==> Using cached archive: /home/spack/spack/var/spack/cache/_source-cache/archive/2e/2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825.tar.gz
==> Staging archive: /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-3qzsur4suru5pdaoi6cze3vyrxkbd6bh/mpileaks-1.0.tar.gz
==> Created stage in /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-3qzsur4suru5pdaoi6cze3vyrxkbd6bh
==> No patches needed for mpileaks
==> Building mpileaks [AutotoolsPackage]
==> Executing phase: 'autoreconf'
==> Executing phase: 'configure'
==> Error: ProcessError: Command exited with status 1:
    '/tmp/spack/spack-stage/spack-stage-mpileaks-1.0-3qzsur4suru5pdaoi6cze3vyrxkbd6bh/spack-src/configure' '--prefix=/home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/mpileaks-1.0-3qzsur4suru5pdaoi6cze3vyrxkbd6bh'

1 error found in build log:
     30    checking for mpipgcc... no
     31    Checking whether not-found responds to '-showme:compile'... no
     32    Checking whether not-found responds to '-showme'... no
     33    Checking whether not-found responds to '-compile-info'... no
     34    Checking whether not-found responds to '-show'... no
     35    /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-3qzsur4suru5pdaoi6cze3vyrxkbd6bh/spack-
           src/configure: line 4931: Echo: command not found
  >> 36    configure: error: unable to locate adept-utils installation

See build log for details:
  /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-3qzsur4suru5pdaoi6cze3vyrxkbd6bh/spack-build-out.txt

This obviously didn’t work; we need to fill in the package-specific information. Specifically, Spack didn’t try to build any of mpileaks’ dependencies, nor did it use the proper configure arguments. Let’s start fixing things.

Package Documentation

We can bring the package.py file back into our $EDITOR with the spack edit command:

$ spack edit mpileaks

Let’s remove some of the FIXME comments, add a link to the mpileaks homepage, and document what mpileaks does. Let’s also add a maintainer to the package. The maintainers field is a comma-separated list of GitHub accounts of users who want to be notified when a change is made to a package. This is useful for developers who maintain a Spack package for their own software, and for users who rely on a piece of software and want to ensure that the package doesn’t break.

I’m also going to cut out the Copyright clause at this point to keep this tutorial document shorter, but you shouldn’t do that normally. Make these changes to your package.py:

tutorial/examples/1.package.py
from spack import *


class Mpileaks(AutotoolsPackage):
    """Tool to detect and report MPI objects like MPI_Requests and
    MPI_Datatypes."""

    homepage = "https://github.com/LLNL/mpileaks"
    url      = "https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz"

    maintainers = ['adamjstewart']

    version('1.0', sha256='2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825')

    # FIXME: Add dependencies if required.
    # depends_on('foo')

    def configure_args(self):
        # FIXME: Add arguments other than --prefix
        # FIXME: If not needed delete this function
        args = []
        return args

We’ve filled in the comment that describes what this package does and added a link to its website. That won’t help us build yet, but it will allow Spack to provide some documentation on this package to other users:

$ spack info mpileaks
AutotoolsPackage:   mpileaks

Description:
    Tool to detect and report MPI objects like MPI_Requests and
    MPI_Datatypes.

Homepage: https://github.com/LLNL/mpileaks

Maintainers: @adamjstewart

Tags:
    None

Preferred version:
    1.0    https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz

Safe versions:
    1.0    https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz

Variants:
    None

Installation Phases:
    autoreconf    configure    build    install

Build Dependencies:
    None

Link Dependencies:
    None

Run Dependencies:
    None

Virtual Packages:
    None

As we fill in more information about this package the spack info command will become more informative. Now let’s start making this package build.

Dependencies

The mpileaks package depends on three other packages: mpi, adept-utils, and callpath. Let’s add those via the depends_on command in our package.py.

tutorial/examples/2.package.py
from spack import *


class Mpileaks(AutotoolsPackage):
    """Tool to detect and report MPI objects like MPI_Requests and
    MPI_Datatypes."""

    homepage = "https://github.com/LLNL/mpileaks"
    url      = "https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz"

    maintainers = ['adamjstewart']

    version('1.0', sha256='2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825')

    depends_on('mpi')
    depends_on('adept-utils')
    depends_on('callpath')

    def configure_args(self):
        # FIXME: Add arguments other than --prefix
        # FIXME: If not needed delete this function
        args = []
        return args

Now when we go to build mpileaks, Spack will fetch and build these dependencies before building mpileaks. Normally, we would also need to create package.py recipes for these dependencies as well. Luckily, all of these dependencies are already in Spack.

Note that the mpi dependency is a different kind of beast than the adept-utils and callpath dependencies; there is no mpi package available in Spack. Instead mpi is a virtual dependency. Spack may satisfy that dependency by installing packages such as openmpi or mvapich2. See the Packaging Guide for more information on virtual dependencies.

Now when we try to install this package, a lot more happens:

$ spack install mpileaks
...
==> Installing callpath
==> Searching for binary cache of callpath
==> Fetching file:///mirror/build_cache/linux-ubuntu18.04-x86_64/gcc-7.4.0/callpath-1.0.4/linux-ubuntu18.04-x86_64-gcc-7.4.0-callpath-1.0.4-67ca64hu2bc2a6l24q6qng3gdcmutumm.spack
########################################################################################################################################### 100.0%
==> Installing callpath from binary cache
==> Relocating package from
  /spack/opt/spack to /home/spack/spack/opt/spack.
==> Successfully installed callpath from binary cache
[+] /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/callpath-1.0.4-67ca64hu2bc2a6l24q6qng3gdcmutumm
==> Installing mpileaks
==> Searching for binary cache of mpileaks
==> No binary for mpileaks found: installing from source
==> Using cached archive: /home/spack/spack/var/spack/cache/_source-cache/archive/2e/2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825.tar.gz
==> Staging archive: /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2/mpileaks-1.0.tar.gz
==> Created stage in /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2
==> No patches needed for mpileaks
==> Building mpileaks [AutotoolsPackage]
==> Executing phase: 'autoreconf'
==> Executing phase: 'configure'
==> Error: ProcessError: Command exited with status 1:
    '/tmp/spack/spack-stage/spack-stage-mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2/spack-src/configure' '--prefix=/home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2'

1 error found in build log:
     23    checking whether /home/spack/spack/lib/spack/env/gcc/gcc and cc understand -c and -o together... yes
     24    checking whether we are using the GNU C++ compiler... yes
     25    checking whether /home/spack/spack/lib/spack/env/gcc/g++ accepts -g... yes
     26    checking dependency style of /home/spack/spack/lib/spack/env/gcc/g++... gcc3
     27    checking for /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc..
           . /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc
     28    Checking whether /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpi
           cc responds to '-showme:compile'... yes
  >> 29    configure: error: unable to locate adept-utils installation

See build log for details:
  /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2/spack-build-out.txt

Note that this command may take a while to run and produce more output if you don’t have an MPI already installed or configured in Spack.

Now Spack has identified and made sure all of our dependencies have been built. It found the openmpi package that will satisfy our mpi dependency, and the callpath and adept-utils package to satisfy our concrete dependencies.

Debugging Package Builds

Our mpileaks package is still not building. For experienced Autotools developers, the problem and its solution may be obvious. But let’s instead use this opportunity to spend some time debugging. We have a few options that can tell us about what’s going wrong:

As per the error message, Spack has given us a spack-build-out.txt debug log:

==> Executing phase: 'autoreconf'
==> Executing phase: 'configure'
==> [2019-11-17-19:25:30.481411] '/tmp/spack/spack-stage/spack-stage-mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2/spack-src/configure' '--prefix=/home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2'
checking metadata... no
checking installation directory variables... yes
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for gawk... no
checking for mawk... mawk
checking whether make sets $(MAKE)... yes
checking for gcc... /home/spack/spack/lib/spack/env/gcc/gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether /home/spack/spack/lib/spack/env/gcc/gcc accepts -g... yes
checking for /home/spack/spack/lib/spack/env/gcc/gcc option to accept ISO C89... none needed
checking for style of include used by make... GNU
checking dependency style of /home/spack/spack/lib/spack/env/gcc/gcc... gcc3
checking whether /home/spack/spack/lib/spack/env/gcc/gcc and cc understand -c and -o together... yes
checking whether we are using the GNU C++ compiler... yes
checking whether /home/spack/spack/lib/spack/env/gcc/g++ accepts -g... yes
checking dependency style of /home/spack/spack/lib/spack/env/gcc/g++... gcc3
checking for /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc... /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc
Checking whether /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc responds to '-showme:compile'... yes
configure: error: unable to locate adept-utils installation

This gives us the output from the build, and mpileaks isn’t finding its adept-utils dependency. Spack has automatically added the include and library directories of adept-utils to the compiler’s search path, but some packages like mpileaks can sometimes be picky and still want things spelled out on the command line. But let’s continue to pretend we’re not experienced developers, and explore some other debugging paths.

We can also enter the build area and try to manually run the build:

$ spack cd mpileaks
$ spack build-env mpileaks bash

The spack build-env command spawns a new shell that contains the same environment that Spack used to build the mpileaks package (you can substitute bash for your favorite shell). The spack cd command changed our working directory to the last attempted build for mpileaks. From here we can manually re-run the build:

$ ./configure --prefix=/home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2
checking metadata... no
checking installation directory variables... yes
checking for a BSD-compatible install... /usr/bin/install -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /bin/mkdir -p
checking for gawk... no
checking for mawk... mawk
checking whether make sets $(MAKE)... yes
checking for gcc... /home/spack/spack/lib/spack/env/gcc/gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
checking whether we are using the GNU C compiler... yes
checking whether /home/spack/spack/lib/spack/env/gcc/gcc accepts -g... yes
checking for /home/spack/spack/lib/spack/env/gcc/gcc option to accept ISO C89... none needed
checking for style of include used by make... GNU
checking dependency style of /home/spack/spack/lib/spack/env/gcc/gcc... gcc3
checking whether /home/spack/spack/lib/spack/env/gcc/gcc and cc understand -c and -o together... yes
checking whether we are using the GNU C++ compiler... yes
checking whether /home/spack/spack/lib/spack/env/gcc/g++ accepts -g... yes
checking dependency style of /home/spack/spack/lib/spack/env/gcc/g++... gcc3
checking for /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc... /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc
Checking whether /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/openmpi-3.1.4-f6maodnm53tkmchq5woe33nt5wbt2tel/bin/mpicc responds to '-showme:compile'... yes
configure: error: unable to locate adept-utils installation

We’re seeing the same error, but now we’re in a shell where we can run the command ourselves and debug as needed. We could, for example, run ./configure --help to see what options we can use to specify dependencies.

We can use the exit command to leave the shell spawned by spack build-env.

Specifying Configure Arguments

Let’s add the configure arguments to the mpileaks’ package.py.

tutorial/examples/3.package.py
from spack import *


class Mpileaks(AutotoolsPackage):
    """Tool to detect and report MPI objects like MPI_Requests and
    MPI_Datatypes."""

    homepage = "https://github.com/LLNL/mpileaks"
    url      = "https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz"

    maintainers = ['adamjstewart']

    version('1.0', sha256='2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825')

    depends_on('mpi')
    depends_on('adept-utils')
    depends_on('callpath')

    def configure_args(self):
        args = [
            '--with-adept-utils={0}'.format(self.spec['adept-utils'].prefix),
            '--with-callpath={0}'.format(self.spec['callpath'].prefix)
        ]

        return args

This is all we need for a working mpileaks package! If we install now we’ll see:

$ spack install mpileaks
...
==> Installing mpileaks
==> Searching for binary cache of mpileaks
==> Finding buildcaches in /mirror/build_cache
==> No binary for mpileaks found: installing from source
==> Using cached archive: /home/spack/spack/var/spack/cache/_source-cache/archive/2e/2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825.tar.gz
==> Staging archive: /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2/mpileaks-1.0.tar.gz
==> Created stage in /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2
==> No patches needed for mpileaks
==> Building mpileaks [AutotoolsPackage]
==> Executing phase: 'autoreconf'
==> Executing phase: 'configure'
==> Executing phase: 'build'
==> Executing phase: 'install'
==> Successfully installed mpileaks
  Fetch: 0.02s.  Build: 1m 0.46s.  Total: 1m 0.48s.
[+] /home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/mpileaks-1.0-g4wqm3n33mzlxww6vgs6piu4gm5bvnb2

Variants

We have a successful mpileaks build, but let’s take some time to improve it. mpileaks has a build-time option to truncate parts of the stack that it walks. Let’s add a variant to allow users to set this when they build mpileaks with Spack.

To do this, we’ll add a variant to our package, as per the following:

tutorial/examples/4.package.py
from spack import *


class Mpileaks(AutotoolsPackage):
    """Tool to detect and report MPI objects like MPI_Requests and
    MPI_Datatypes."""

    homepage = "https://github.com/LLNL/mpileaks"
    url      = "https://github.com/LLNL/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz"

    maintainers = ['adamjstewart']

    version('1.0', sha256='2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825')

    variant('stackstart', values=int, default=0,
            description='Specify the number of stack frames to truncate')

    depends_on('mpi')
    depends_on('adept-utils')
    depends_on('callpath')

    def configure_args(self):
        args = [
            '--with-adept-utils={0}'.format(self.spec['adept-utils'].prefix),
            '--with-callpath={0}'.format(self.spec['callpath'].prefix),
        ]

        stackstart = int(self.spec.variants['stackstart'].value)
        if stackstart:
            args.extend([
                '--with-stack-start-c={0}'.format(stackstart),
                '--with-stack-start-fortran={0}'.format(stackstart)
            ])

        return args

We’ve added the variant stackstart, and given it a default value of 0. If we install now we can see the stackstart variant added to the configure line (output truncated for length):

$ spack install --verbose mpileaks stackstart=4
...
==> Installing mpileaks
==> Searching for binary cache of mpileaks
==> Finding buildcaches in /mirror/build_cache
==> No binary for mpileaks found: installing from source
==> Using cached archive: /home/spack/spack/var/spack/cache/_source-cache/archive/2e/2e34cc4505556d1c1f085758e26f2f8eea0972db9382f051b2dcfb1d7d9e1825.tar.gz
==> Staging archive: /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-ih6fqd7kewpqigkot3fqqqwqifqppglq/mpileaks-1.0.tar.gz
==> Created stage in /tmp/spack/spack-stage/spack-stage-mpileaks-1.0-ih6fqd7kewpqigkot3fqqqwqifqppglq
==> No patches needed for mpileaks
==> Building mpileaks [AutotoolsPackage]
==> Executing phase: 'autoreconf'
==> Executing phase: 'configure'
==> [2019-11-17-19:42:10.493951] '/tmp/spack/spack-stage/spack-stage-mpileaks-1.0-ih6fqd7kewpqigkot3fqqqwqifqppglq/spack-src/configure' '--prefix=/home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/mpileaks-1.0-ih6fqd7kewpqigkot3fqqqwqifqppglq' '--with-adept-utils=/home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/adept-utils-1.0.1-kzcrayeek3kccpor44m5bjflmrrqt3jl' '--with-callpath=/home/spack/spack/opt/spack/linux-ubuntu18.04-x86_64/gcc-7.4.0/callpath-1.0.4-67ca64hu2bc2a6l24q6qng3gdcmutumm' '--with-stack-start-c=4' '--with-stack-start-fortran=4'
...

The Spec Object

This tutorial has glossed over a few important features, which weren’t too relevant for mpileaks but may be useful for other packages. There were several places we reference the self.spec object. This is a powerful class for querying information about what we’re building. For example, you could use the spec to query information about how a package’s dependencies were built, or what compiler was being used, or what version of a package is being installed. Full documentation can be found in the Packaging Guide, but here’s some quick snippets with common queries:

  • Am I building mpileaks version 1.1 or greater?

if self.spec.satisfies('@1.1:'):
    # Do things needed for 1.1+
  • Is openmpi the MPI I’m building with?

if self.spec['mpi'].name == 'openmpi':
    # Do openmpi things
  • Am I building with gcc version less than 5.0.0:

if self.spec.satisfies('%gcc@:5.0.0'):
    # Add arguments specific to gcc's earlier than 5.0.0
  • Am I building with the debug variant:

if '+debug' in self.spec:
    # Add -g option to configure flags
  • Is my dyninst dependency greater than version 8.0?

if self.spec['dyninst'].satisfies('@8.0:'):
    # Use newest dyninst options

More examples can be found in the thousands of packages already added to Spack in $SPACK_ROOT/var/spack/repos/builtin/packages.

Good Luck!

Cleaning Up

To ensure that future sections of the tutorial run properly, please uninstall mpileaks and remove the tutorial repo from your configuration.

$ spack uninstall -ay mpileaks
$ spack repo remove tutorial
$ rm -rf $SPACK_ROOT/var/spack/repos/tutorial/packages/mpileaks