Files
spack/var/spack/repos/builtin/packages/esmf/package.py
Massimiliano Culpo 5b3942a489 Turn compilers into nodes (#45189)
## Summary

Compilers stop being a *node attribute*, and become a *build-only* dependency. 

Packages may declare a dependency on the `c`, `cxx`, or `fortran` languages, which
are now treated as virtuals, and compilers would be *providers* for one or more of
those languages. Compilers can also inject runtime dependency, on the node being
compiled. An example graph for something as simple as `zlib-ng` is the following:

<p align="center">
<img src="https://github.com/user-attachments/assets/ee6471cb-09fd-4127-9f16-b9fe6d1338ac" alt="zlib-ng DAG" width="80%" height="auto">
</p>

Here `gcc` is used for both the `c`, and `cxx` languages. Edges are annotated with
the virtuals they satisfy (`c`, `cxx`, `libc`). `gcc` injects `gcc-runtime` on the nodes
being compiled. `glibc` is also injected for packages that require `c`. The
`compiler-wrapper` is explicitly represented as a node in the DAG, and is included in
the hash.

This change in the model has implications on the semantics of the `%` sigil, as
discussed in #44379, and requires a version bump for our `Specfile`, `Database`,
and `Lockfile` formats.

## Breaking changes

Breaking changes below may impact users of this branch.

### 1. Custom, non-numeric version of compilers are not supported

Currently, users can assign to compilers any custom version they want, and Spack
will try to recover the "real version" whenever the custom version fails some operation.
To deduce the "real version" Spack must run the compiler, which can add needless
overhead to common operations.

Since any information that a version like `gcc@foo` might give to the user, can also
be suffixed while retaining the correct numeric version, e.g. `gcc@10.5.0-foo`, Spack
will **not try** anymore to deduce real versions for compilers.

Said otherwise, users should have no expectation that `gcc@foo` behaves as
`gcc@X.Y.Z` internally.

### 2. The `%` sigil in the spec syntax means "direct build dependency"

The `%` sigil in the spec syntax means *"direct build dependency"*, and is not a node
attribute anymore. This means that:

```python
node.satisfies("%gcc")
``` 
is true only if `gcc` is a direct build dependency of the node. *Nodes without a compiler
dependency are allowed.*

### `parent["child"]`, and `node in spec`, will now only inspect the link/run sub-DAG
and direct build dependencies

The subscript notation for `Spec`:

```python
parent["child"]
```

will look for a `child` node only in the link/run transitive graph of `parent`, and in its
direct build dependencies. This means that to reach a transitive build dependency,
we must first pass through the node it is associated with. 

Assuming `parent` does not depend on `cmake`, but depends on a `CMakePackage`,
e.g. `hdf5`, then we have the following situation:

```python
# This one raises an Exception, since "parent" does not depend on cmake
parent["cmake"]
# This one is ok
cmake = parent["hdf5"]["cmake"]
```

### 3. Externals differing by just the compiler attribute

Externals are nodes where dependencies are trimmed, and that _is not planned to
change_ in this branch. Currently, on `develop` it is ok to write:

```yaml
packages:
  hdf5:
    externals:
    - spec: hdf5@1.12 %gcc
      prefix: /prefix/gcc
    - spec: hdf5@1.12 %clang
      prefix: /prefix/clang
```
and Spack will account for the compiler node attribute when computing the optimal
spec. In this branch, using externals with a compiler specified is allowed only if any
compiler in the dag matches the constraints specified on the external. _The external
will be still represented as a single node without dependencies_.

### 4. Spec matrices enforcing a compiler

Currently we can have matrices of the form:

```yaml
matrix:
- [x, y, z]
- [%gcc, %clang]
```
to get the cross-product of specs and compilers. We can disregard the nature of the
packages in the first row, since the compiler is a node attribute required on each node.

In this branch, instead, we require a spec to depend on `c`, `cxx`, or `fortran` for the
`%` to have any meaning. If any of the specs in the first row doesn't depend on these
languages, there will be a concretization error. 

## Deprecations

* The entire `compilers` section in the configuration (i.e., `compilers.yaml`) has been
  deprecated, and current entries will be removed in v1.2.0. For the time being, if Spack
  finds any `compilers` configuration, it will try to convert it automatically to a set of
  external packages.
* The `packages:compiler` soft-preference has been deprecated. It will be removed
  in v1.1.0.

## Other notable changes

* The tokens `{compiler}`, `{compiler.version}`, and `{compiler.name}` in `Spec.format`
  expand to `"none"` if a Spec does not depend on C, C++, or Fortran.
* The default install tree layout is now
  `"{architecture.platform}-{architecture.target}/{name}-{version}-{hash}"`

## Known limitations

The major known limitations of this branch that we intend to fix before v1.0 is that compilers
cannot be bootstrapped directly. 

In this branch we can build a new compiler using an existing external compiler, for instance:
	
```
$ spack install gcc@14 %gcc@10.5.0
```

where `gcc@10.5.0` is external, and `gcc@14` is to be built.

What we can't do at the moment is use a yet to be built compiler, and expect it will be
bootstrapped, e.g. :

```
spack install hdf5 %gcc@14
```

We plan to tackle this issue in a following PR.

---------

Signed-off-by: Massimiliano Culpo <massimiliano.culpo@gmail.com>
Signed-off-by: Todd Gamblin <tgamblin@llnl.gov>
Signed-off-by: Harmen Stoppels <me@harmenstoppels.nl>
Co-authored-by: Harmen Stoppels <me@harmenstoppels.nl>
Co-authored-by: Todd Gamblin <tgamblin@llnl.gov>
2025-03-25 22:32:49 -06:00

477 lines
20 KiB
Python

# Copyright Spack Project Developers. See COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)
import os
import sys
import spack.build_systems.makefile
import spack.build_systems.python
from spack.build_environment import dso_suffix, stat_suffix
from spack.package import *
class Esmf(MakefilePackage, PythonExtension):
"""The Earth System Modeling Framework (ESMF) is high-performance, flexible
software infrastructure for building and coupling weather, climate, and
related Earth science applications. The ESMF defines an architecture for
composing complex, coupled modeling systems and includes data structures
and utilities for developing individual models.
The National Unified Operational Prediction Capability (NUOPC) Layer
defines a common model architecture to support interoperable ESMF components.
The NUOPC Layer is included with the ESMF package."""
homepage = "https://earthsystemmodeling.org/"
url = "https://github.com/esmf-org/esmf/archive/v8.4.1.tar.gz"
git = "https://github.com/esmf-org/esmf.git"
maintainers("climbfuji", "jedwards4b", "AlexanderRichert-NOAA", "theurich", "uturuncoglu")
# Develop is a special name for spack and is always considered the newest version
version("develop", branch="develop")
# generate chksum with 'spack checksum esmf@x.y.z'
version("8.8.0", sha256="f89327428aeef6ad34660b5b78f30d1c55ec67efb8f7df1991fdaa6b1eb3a27c")
version("8.7.0", sha256="d7ab266e2af8c8b230721d4df59e61aa03c612a95cc39c07a2d5695746f21f56")
version("8.6.1", sha256="dc270dcba1c0b317f5c9c6a32ab334cb79468dda283d1e395d98ed2a22866364")
version("8.6.0", sha256="ed057eaddb158a3cce2afc0712b49353b7038b45b29aee86180f381457c0ebe7")
version("8.5.0", sha256="acd0b2641587007cc3ca318427f47b9cae5bfd2da8d2a16ea778f637107c29c4")
version("8.4.2", sha256="969304efa518c7859567fa6e65efd960df2b4f6d72dbf2c3f29e39e4ab5ae594")
version("8.4.1", sha256="1b54cee91aacaa9df400bd284614cbb0257e175f6f3ec9977a2d991ed8aa1af6")
version(
"8.4.0",
sha256="28531810bf1ae78646cda6494a53d455d194400f19dccd13d6361871de42ed0f",
deprecated=True,
)
version("8.3.1", sha256="6c39261e55dcdf9781cdfa344417b9606f7f961889d5ec626150f992f04f146d")
version(
"8.3.0",
sha256="0ff43ede83d1ac6beabd3d5e2a646f7574174b28a48d1b9f2c318a054ba268fd",
deprecated=True,
)
version("8.3.0b09", commit="5b7e546c4ba350bff9c9ebd00e5fa1c6315d17da", deprecated=True)
version("8.2.0", sha256="27866c31fdb63c58e78211de970470ca02d274f5d4d6d97e94284d63b1c1d9e4")
version("8.1.1", sha256="629690c7a488e84ac7252470349458d7aaa98b54c260f8b3911a2e2f3e713dd0")
version(
"8.1.0",
sha256="226219ec61cace89f4678eece93188155d7cbb50a13ec4c9c93174ef3d58d7c0",
deprecated=True,
)
version("8.0.1", sha256="13ce2ca0ae622548c00f7bb18317fb100235ca8b7ddbfac7e201a339e8eb05a3")
version(
"8.0.0",
sha256="4b7904fdc935710071c4aafb9370834d40c2ee06365a8b5845317be8f71bf51f",
deprecated=True,
)
version(
"7.1.0r",
sha256="e08f21544083dcbe162b472852e321f8df14f4f711f35508403d32df438367a7",
deprecated=True,
)
depends_on("c", type="build") # generated
depends_on("cxx", type="build") # generated
depends_on("fortran", type="build") # generated
variant("mpi", default=True, description="Build with MPI support")
variant("external-lapack", default=False, description="Build with external LAPACK library")
variant("netcdf", default=True, description="Build with NetCDF support")
variant("pnetcdf", default=False, description="Build with pNetCDF support")
variant("xerces", default=False, description="Build with Xerces support")
variant(
"external-parallelio",
default=True,
description="Build with external parallelio library",
when="@8.3.1:",
)
variant("debug", default=False, description="Build with debugging symbols and options enabled")
variant("shared", default=True, description="Build shared library")
# 'esmf_os', 'esmf_comm', 'esmf_pio' variants allow override values for their corresponding
# build environment variables. Documentation, including valid values, can be found at
# https://earthsystemmodeling.org/docs/release/latest/ESMF_usrdoc/node10.html#SECTION000105000000000000000
variant("esmf_os", default="auto", description="Override for ESMF_OS variable")
variant("esmf_comm", default="auto", description="Override for ESMF_COMM variable")
variant("esmf_pio", default="auto", description="Override for ESMF_PIO variable")
# Set the 'snapshot' variant any time a beta snapshot is used in order to obtain
# correct module name behavior for MAPL.
variant(
"snapshot",
default="none",
description="Named variant for snapshots versions (e.g., 'b09')",
)
# The way python is handled here is only avialable >=8.4.0
# https://github.com/esmf-org/esmf/releases/tag/v8.4.0
variant("python", default=False, description="Build python bindings", when="@8.4.0:")
# Optional dependencies
depends_on("mpi", when="+mpi")
depends_on("lapack@3:", when="+external-lapack")
depends_on("netcdf-c@3.6:", when="+netcdf")
depends_on("netcdf-fortran@3.6:", when="+netcdf")
depends_on("parallel-netcdf@1.2.0:", when="+pnetcdf")
depends_on("xerces-c@3.1.0:", when="+xerces")
depends_on("parallelio@2.5.7: +mpi", when="@8.3+external-parallelio+mpi")
depends_on("parallelio@2.5.7: ~mpi", when="@8.3+external-parallelio~mpi")
depends_on("parallelio@2.5.9: +mpi", when="@8.4+external-parallelio+mpi")
depends_on("parallelio@2.5.9: ~mpi", when="@8.4+external-parallelio~mpi")
depends_on("parallelio@2.5.10: +mpi", when="@8.5:+external-parallelio+mpi")
depends_on("parallelio@2.5.10: ~mpi", when="@8.5:+external-parallelio~mpi")
depends_on("cmake@3.5.2:", type="build", when="~external-parallelio")
# python library
with when("+python"):
extends("python")
depends_on("py-pip")
depends_on("py-setuptools", type="build")
depends_on("py-wheel", type="build")
depends_on("py-mpi4py", when="+mpi")
depends_on("py-numpy")
# In esmf@8.4.0, esmx was introduced which depends on py-pyyaml
with when("@8.4.0:"):
depends_on("python", type="run")
depends_on("py-pyyaml", type="run")
# Testing dependencies
depends_on("perl", type="test")
conflicts("%aocc", when="@:8.3")
# Make esmf build with newer intel versions
patch("intel.patch", when="@:7.0 %intel@17:")
# Make esmf build with newer gcc versions
# https://sourceforge.net/p/esmf/esmf/ci/3706bf758012daebadef83d6575c477aeff9c89b/
patch("gcc.patch", when="@:7.0 %gcc@6:")
# Fix undefined reference errors with mvapich2
# https://sourceforge.net/p/esmf/esmf/ci/34de0ccf556ba75d35c9687dae5d9f666a1b2a18/
patch("mvapich2.patch", when="@:7.0")
# explicit type cast of variables from long to int
patch("longtoint.patch", when="@:8.3.2 %cce@14:")
patch("longtoint.patch", when="@:8.3.2 %oneapi@2022:")
# Allow different directories for creation and
# installation of dynamic libraries on OSX:
patch("darwin_dylib_install_name.patch", when="platform=darwin @:7.0")
# Missing include file for newer gcc compilers
# https://trac.macports.org/ticket/57493
patch("cstddef.patch", when="@7.1.0r %gcc@8:")
# Skip info print of ESMF_CPP due to permission denied errors
# https://github.com/spack/spack/issues/35957
patch("esmf_cpp_info.patch")
@when("+python")
def patch(self):
# The pyproject.toml file uses a dynamically generated version from git
# However, this results in a version of 0.0.0 and a mismatch with the loaded version
# so this hardcodes it to match the library's version
filter_file(
"""dynamic = \\[\\s+"version"\\s+\\]""",
f"""version = "{self.version}" """,
os.path.join("src/addon/esmpy/pyproject.toml"),
)
def setup_run_environment(self, env):
env.set("ESMFMKFILE", os.path.join(self.prefix.lib, "esmf.mk"))
class PythonPipBuilder(spack.build_systems.python.PythonPipBuilder):
@property
def build_directory(self):
return os.path.join(self.stage.source_path, "src/addon/esmpy")
class MakefileBuilder(spack.build_systems.makefile.MakefileBuilder):
# This is strictly required on Cray systems that use
# the Cray compiler wrappers, where we need to swap
# out the spack compiler wrappers in esmf.mk with the
# Cray wrappers. It doesn't hurt/have any effect on
# other systems where the logic in setup_build_environment
# below sets the compilers to the MPI wrappers.
filter_compiler_wrappers("esmf.mk", relative_root="lib")
# Make script from mvapich2.patch executable
@when("@:7.0")
@run_before("build")
def chmod_scripts(self):
chmod = which("chmod")
chmod("+x", "scripts/libs.mvapich2f90")
def url_for_version(self, version):
if version < Version("8.0.0"):
# Older ESMF releases had a custom tag format ESMF_x_y_z
return "https://github.com/esmf-org/esmf/archive/ESMF_{0}.tar.gz".format(
version.underscored
)
else:
# Starting with ESMF 8.0.0 releases are in the form vx.y.z
return "https://github.com/esmf-org/esmf/archive/refs/tags/v{0}.tar.gz".format(
version.dotted
)
def setup_build_environment(self, env):
spec = self.spec
# Installation instructions can be found at:
# http://www.earthsystemmodeling.org/esmf_releases/last_built/ESMF_usrdoc/node9.html
# Unset any environment variables that may influence the installation.
for var in os.environ:
if var.startswith("ESMF_"):
env.unset(var)
######################################
# Build and Installation Directories #
######################################
# The environment variable ESMF_DIR must be set to the full pathname
# of the top level ESMF directory before building the framework.
env.set("ESMF_DIR", self.stage.source_path)
# This variable specifies the prefix of the installation path used
# with the install target.
env.set("ESMF_INSTALL_PREFIX", prefix)
# Installation subdirectories default to:
# bin/binO/Linux.gfortran.64.default.default
env.set("ESMF_INSTALL_BINDIR", "bin")
env.set("ESMF_INSTALL_LIBDIR", "lib")
env.set("ESMF_INSTALL_MODDIR", "include")
# Allow compiler flags to carry through from compiler spec
env.set("ESMF_CXXCOMPILEOPTS", " ".join(spec.compiler_flags["cxxflags"]))
env.set("ESMF_F90COMPILEOPTS", " ".join(spec.compiler_flags["fflags"]))
# ESMF will simply not build with Intel using backing GCC 8, in that
# case you need to point to something older, below is commented but is
# an example
# env.set("ESMF_CXXCOMPILEOPTS", "-O2 -std=c++11 -gcc-name=/usr/bin/gcc")
# env.set("ESMF_F90COMPILEOPTS", "-O2 -gcc-name=/usr/bin/gcc")
############
# Compiler #
############
# ESMF_COMPILER must be set to select which Fortran and
# C++ compilers are being used to build the ESMF library.
if spec["fortran"].name == "gcc" and spec["c"].name == "gcc":
gfortran_major_version = int(spec["fortran"].version[0])
env.set("ESMF_COMPILER", "gfortran")
elif self.pkg.compiler.name == "intel" or self.pkg.compiler.name == "oneapi":
env.set("ESMF_COMPILER", "intel")
elif spec["fortran"].name == "gcc" and spec["c"].name in ["clang", "apple-clang"]:
gfortran_major_version = int(spec["fortran"].version[0])
env.set("ESMF_COMPILER", "gfortranclang")
elif spec["fortran"].name == "llvm":
env.set("ESMF_COMPILER", "llvm")
elif self.pkg.compiler.name == "nag":
env.set("ESMF_COMPILER", "nag")
elif self.pkg.compiler.name == "nvhpc":
env.set("ESMF_COMPILER", "nvhpc")
elif self.pkg.compiler.name == "cce":
env.set("ESMF_COMPILER", "cce")
elif self.pkg.compiler.name == "aocc":
env.set("ESMF_COMPILER", "aocc")
else:
msg = "The compiler you are building with, "
msg += '"{0}", is not supported by ESMF.'
raise InstallError(msg.format(self.pkg.compiler.name))
if spec.satisfies("+mpi"):
env.set("ESMF_CXX", spec["mpi"].mpicxx)
env.set("ESMF_C", spec["mpi"].mpicc)
env.set("ESMF_F90", spec["mpi"].mpifc)
else:
env.set("ESMF_CXX", spack_cxx)
env.set("ESMF_C", spack_cc)
env.set("ESMF_F90", spack_fc)
# This environment variable controls the build option.
if spec.satisfies("+debug"):
# Build a debuggable version of the library.
env.set("ESMF_BOPT", "g")
else:
# Build an optimized version of the library.
env.set("ESMF_BOPT", "O")
if (
self.pkg.compiler.name in ["gcc", "clang", "apple-clang"]
and "gfortran" in self.pkg.compiler.fc
and gfortran_major_version >= 10
and (self.spec.satisfies("@:8.2.99") or self.spec.satisfies("@8.3.0b09"))
):
env.set("ESMF_F90COMPILEOPTS", "-fallow-argument-mismatch")
#######
# OS #
#######
# ESMF_OS must be set for Cray systems
# But spack no longer gives arch == cray
if self.pkg.compiler.name == "cce" or "^cray-mpich" in self.spec:
env.set("ESMF_OS", "Unicos")
# Allow override of ESMF_OS:
os_variant = spec.variants["esmf_os"].value
if os_variant != "auto":
env.set("ESMF_OS", os_variant)
#######
# MPI #
#######
# ESMF_COMM must be set to indicate which MPI implementation
# is used to build the ESMF library.
if spec.satisfies("+mpi"):
if self.spec.satisfies("^[virtuals=mpi] cray-mpich"):
env.set("ESMF_COMM", "mpi")
# https://github.com/jcsda/spack-stack/issues/517
if self.spec.satisfies("@:8.4.1"):
env.set("ESMF_CXXLINKLIBS", "-lmpifort -lmpi")
elif spec.satisfies("^[virtuals=mpi] mvapich2"):
env.set("ESMF_COMM", "mvapich2")
elif spec.satisfies("^[virtuals=mpi] mpich"):
if self.spec.satisfies("@:8.2.99"):
env.set("ESMF_COMM", "mpich3")
else:
env.set("ESMF_COMM", "mpich")
elif spec.satisfies("^[virtuals=mpi] openmpi") or spec.satisfies(
"^[virtuals=mpi] hpcx-mpi"
):
env.set("ESMF_COMM", "openmpi")
elif (
spec.satisfies("^[virtuals=mpi] intel-parallel-studio+mpi")
or spec.satisfies("^[virtuals=mpi] intel-mpi")
or spec.satisfies("^[virtuals=mpi] intel-oneapi-mpi")
):
env.set("ESMF_COMM", "intelmpi")
elif spec.satisfies("^[virtuals=mpi] mpt"):
# MPT is the HPE (SGI) variant of mpich
env.set("ESMF_COMM", "mpt")
else:
# Force use of the single-processor MPI-bypass library.
env.set("ESMF_COMM", "mpiuni")
# Allow override of ESMF_COMM:
comm_variant = spec.variants["esmf_comm"].value
if comm_variant != "auto":
env.set("ESMF_COMM", comm_variant)
##########
# LAPACK #
##########
if spec.satisfies("+external-lapack"):
# A system-dependent external LAPACK/BLAS installation is used
# to satisfy the external dependencies of the LAPACK-dependent
# ESMF code.
env.set("ESMF_LAPACK", "system")
# Specifies the path where the LAPACK library is located.
env.set("ESMF_LAPACK_LIBPATH", spec["lapack"].prefix.lib)
# Specifies the linker directive needed to link the LAPACK library
# to the application.
env.set("ESMF_LAPACK_LIBS", spec["lapack"].libs.link_flags) # noqa
else:
env.set("ESMF_LAPACK", "internal")
##########
# NetCDF #
##########
if spec.satisfies("+netcdf"):
# ESMF provides the ability to read Grid and Mesh data in
# NetCDF format.
env.set("ESMF_NETCDF", "nc-config")
env.set("ESMF_NFCONFIG", "nf-config")
netcdfc = spec["netcdf-c"]
if netcdfc.satisfies("~shared"):
nc_config = which(os.path.join(netcdfc.prefix.bin, "nc-config"))
nc_flags = nc_config("--static", "--libs", output=str).strip()
env.set("ESMF_NETCDF_LIBS", nc_flags)
###################
# Parallel-NetCDF #
###################
if spec.satisfies("+pnetcdf"):
# ESMF provides the ability to write Mesh weights
# using Parallel-NetCDF.
# When defined, enables the use of Parallel-NetCDF.
# ESMF_PNETCDF_LIBS will be set to "-lpnetcdf".
env.set("ESMF_PNETCDF", "pnetcdf-config")
##############
# ParallelIO #
##############
if spec.satisfies("+external-parallelio"):
env.set("ESMF_PIO", "external")
env.set("ESMF_PIO_LIBPATH", spec["parallelio"].prefix.lib)
env.set("ESMF_PIO_INCLUDE", spec["parallelio"].prefix.include)
# Allow override of ESMF_PIO:
pio_variant = spec.variants["esmf_pio"].value
if pio_variant != "auto":
env.set("ESMF_PIO", pio_variant)
##########
# XERCES #
##########
if spec.satisfies("+xerces"):
# ESMF provides the ability to read Attribute data in
# XML file format via the XERCES C++ library.
# ESMF_XERCES_LIBS will be set to "-lxerces-c".
env.set("ESMF_XERCES", "standard")
# FIXME: determine if the following are needed
# ESMF_XERCES_INCLUDE
# ESMF_XERCES_LIBPATH
#########################
# General build options #
#########################
# Static-only option:
if spec.satisfies("~shared"):
env.set("ESMF_SHARED_LIB_BUILD", "OFF")
# https://github.com/JCSDA/spack-stack/issues/956
if spec.satisfies("+shared"):
if sys.platform == "darwin":
env.set("ESMF_TRACE_LIB_BUILD", "OFF")
@run_after("install")
def post_install(self):
install_tree("cmake", self.prefix.cmake)
# Several applications using ESMF are affected by CMake
# capitalization issue. The following fix allows all apps
# to use as-is. Note that since the macOS file system is
# case-insensitive, this step is not allowed on macOS.
if sys.platform != "darwin":
for prefix in [dso_suffix, stat_suffix]:
library_path = os.path.join(self.prefix.lib, "libesmf.%s" % prefix)
if os.path.exists(library_path):
os.symlink(library_path, os.path.join(self.prefix.lib, "libESMF.%s" % prefix))
def check(self):
make("check", parallel=False)
def setup_dependent_build_environment(self, env, dependent_spec):
env.set("ESMFMKFILE", os.path.join(self.prefix.lib, "esmf.mk"))
def install(self, pkg, spec, prefix):
make("install")
if spec.satisfies("+python"):
# build the python library
python_builder = PythonPipBuilder(pkg)
python_builder.install(pkg, spec, prefix)