pyrate¶
pyrate is a small python based build file generator targeting ninja(s).
It allows to describe the build process of small projects in a very simple way using a python based configuration file. This description is then turned into ninja build files, that enable a very quick turnaround of project builds.
Quick HOWTO¶
The following presents the necessary steps to quickly test the waters with this tool (assuming ninja is already installed). These commands will install pyrate, generate the ninja build file, build and execute a small executable:
pip install pyrate-build
echo -e '#include <cstdio>\nint main() { printf("Ahoy World!"); return 0; }' > test.cpp
echo -e "executable('test', 'test.cpp')" > build.py
pyrate
ninja
./test
More examples can be found in the github repository.
Installation¶
pyrate is very easy to deploy - there are no particular installation steps to use it
once the single script pyrate.py
is available somewhere.
It can even board the project directory of your project and simply get called from there.
The only dependency to generate the ninja build files is having a working python installation.
pyrate should work out of the box with all python versions between 2.4 and 3.4.
To actually build the project, ninja has to be installed as well.
The latest release version of pyrate can be installed from the Python Package Index with:
pip install pyrate-build
The latest development version can be retrieved from the github repository:
git clone https://github.com/pyrate-build/pyrate-build
Usage¶
The quickest way to execute pyrate is:
pyrate
Without any parameters, pyrate will use the build configuration script (pyrate script) named build.py
and create a ninja build file called build.ninja
.
If another pyrate script should be used, this can be specified as a positional argument.
The name of the created ninja build file can be customized using the option -o
or --output
.
The quick invocation shown above is therefore equivalent to the following invocation:
pyrate --output mybuild.ninja mybuild.py
When the script is started, it first changes the current directory to the directory containing the build configuration script, so all path names are relative to it.
pyrate path/to/mybuild.py
will therefore create the ninja build file path/to/build.ninja
If pyrate is placed in a directory listed in the PATH environment variable (as automatically
done by pip install pyrate-build
), the build configure script can be made executable to
invoke pyrate automatically by starting the build config script with:
#!/usr/bin/env pyrate
There is some experimental support for the generation of plain makefiles,
which can be switched on with -M
or --makefile
.
Build File Configuration Syntax¶
The build configuration for pyrate is written in python - so the full power of python can be used to construct and describe the build process. Several classes, functions and variables are available to ease and customize the configuration of the build process.
Specifying build input¶
In general, a build input list that can be used to construct a build target takes the form:
[<item1>, <item2>, ...]
Each item can be one of the following:
- a string is interpreted as a file name that is processed according to the rules specified by the packages in the
tool
dictionary - a build target as returned by the functions described in Defining build targets or explicitly defined
- an external dependency as returned by the functions described in External dependencies or explicitly defined
- or any other kind of
BuildSource
(explained later)
Instead of a list, it is also possible to specify a space separated string of file names. Such a string is automatically split, so the following two build input lists behave identically:
"<file1> <file2> ..."
['<file1>', '<file2>', ...]
Besides specifying file names by hand, there are many ways to get a list of files.
Common methods include calling the python function os.listdir
or using the helper
function match
provided by pyrate:
match(selector, dir_name = '.', recurse = False)
This functions allows to select files from a directory using a string consisting
of black / white listing path name patterns.
The selector '*.cpp -test*.cpp test3.cpp *.h'
for example selects all files ending with
‘.h’ and ‘.cpp’, with the exception of those ‘.cpp’ files that start with ‘test’ and are not
called ‘test3.cpp’.
Defining build targets¶
There are four global helper functions to define object files, executables and libraries based on a list of build inputs (which can be files, other targets or externals - as shown in Specifying build input):
executable(name, input_list, compiler_opts = None, linker_opts = None)
shared_library(name, input_list = None, compiler_opts = None, linker_opts = None)
static_library(name, input_list = None, compiler_opts = None, linker_opts = None)
object_file(name, input_list, compiler_opts = None)
Each function returns a build target object, that can be used as input / dependency of another function. If multiple executables / libraries or object files with the same name but different inputs / options are defined, pyrate will ensure that the output will have a unique name (by appending a hash based suffix as needed). More details about this is available in Target Collision Avoidance.
If no input_list is given to shared_library
or static_library
, a BuildSource will be created,
that represents the specified library. Existing libraries can quickly be defined as dependencies this way,
but the name has to be a path to an existing file!
These functions exist as global functions and as member functions of a so-called build context, that describes how these functions are processed. The global functions are just executing within the default build context.
By default, all build targets that are defined by the above functions (or direct API calls) are built.
In order to select only certain default targets, the global variable default_targets
can be used:
default_targets = [<target>,...]
(list of targets),<target>
(single target) orNone
(all targets are built)
External dependencies¶
The build environment / dependencies on external packages can be expressed using the following functions / variables:
find_external(name, ...)
use_external(name, ...)
The function find_external
searches for some external dependency (built-in, pkg-config package
or self-defined) with the given name and returns either None or a representation of the dependency.
use_external
will first call find_external
and add the external to the implicit input list
of the context if it exists.
The function takes additional positional and keyword arguments that depend on the external package.
A common argument for this function is a version selector, that is supplied through a global variable:
version
The comparison between this variable and a version specifier (eg. version >= 4.1
)
will return a function that can be used to check the expression and is used by the external package finder.
A version specifier can be a string ('0.1.2'
) or tuple ((0, 1, 2)
) with an arbitrary number
of delimeters, or a floating point number (1.2
).
This allows for example to write find_external('clang', version >= 3.5)
to discover a clang installation with version 3.5 or later.
Since find_external
also integrates with pkg-config
, a large number of external packages is
available - in addition to a handful of builtin external packages with special implementation features.
It is also possible to add new packages that are recognized.
A list of the builtin packages is presented in Externals.
In order to simplify the creation of external packages that already provide a build configuration tool to query version, linker or compiler options, pyrate provides the function:
create_external(name, build_helper, ...)
It requires the user to define a name for the external package and to supply the build configuration tool. The values of additional parameters are interpreted as command line options for the build configuration tool. The name of these additional parameters specify the name of the rule that gets supplied with the flags given by the output of the build configuration tool. However there are four parameters that have a special meaning:
version_query
- similar to the other parameters, the value of this parameter is used as build configuration tool option to determine the current version of the external package. As a consequence of providing this option, the resulting external package will support the parameterversion
.version_parser
- this parameter allows to supply a function that parses the version string provided by the build configuration tool and is only used ifversion_query
is given.version
- specifies required version (eg.version = version >= 11.5
) and can only be used ifversion_query
is givenlink = opts
is equivalent to specifyinglink_shared = opts
,link_static = opts
andlink_exe = opts
The following example recreates the builtin external package for wxWidgets and returns a representation of the external package if a matching version is found:
my_wxwidgets = create_external('wxwidgets', build_helper = 'wx-config',
version_query = '--version', link = '--libs', compile_cpp = '--cxxflags',
version = version >= 2.8)
Configuration of the build environment¶
It is possible to query the current version of pyrate via the variable:
pyrate_version
this allows to ensure a compatible version of pyrate with something along the lines of:
assert(pyrate_version > '0.1.8')
A build context allows for example to define implicit dependencies that are automatically
included in all generated object files, executables or libraries (via implicit_*
options).
It is also possible to set base directories for the output generated by the build (via basepath_*
options).
The default context used by the global functions presented in Defining build targets can be set or accessed using the variable:
default_context = Context(...)
An instance of such a build context is created with:
Context(...)
- the most important parameters are:implicit_input
,implicit_object_input
,implicit_static_library_input
,implicit_shared_library_input
andimplicit_executable_input
basepath
,basepath_object_file
,basepath_static_library
,basepath_shared_libray
,basepath_executable
These parameters can also be changed on an existing context instance:
default_context.basepath = 'build'
A context also allows to access some additional settings - which are described in more detail below. These settings are available as member functions of a context or as global variables (that are provided by the default_context):
tools
This is a dictionary that contains links to external packages that provide the basic rules and parameters that are used to process sources and generate targets. This dictionary can be modified, but should not be overwritten.toolchain
This is a list ofToolchain
instances that is used to populate the tools dictionary in reverse order. There are currently two toolchains available:gcc
andllvm
They can be accessed with the follwing two methods:find_toolchain(name, ...)
use_toolchain(name, ...)
These methods work in the same way as thefind_external
anduse_external
methods. The available toolchains and their options are presented in Toolchains. The following example would try to set the clang / clang++ compiler and llvm linker in the tool dictionary
use_toolchain('llvm', version >= 3.7, cpp_std = 'c++11', cpp_opts = '-Wall')
# is the same as
llvm = find_toolchain('llvm', version >= 3.7, cpp_std = 'c++11', cpp_opts = '-Wall')
if llvm:
toolchain.append(llvm)
Target Collision Avoidance¶
As explained in Defining build targets, pyrate will always ensure that targets with different inputs / options but
same name will generate different output files (by appending a hash based suffix as needed).
However it is possible to switch off the renaming of colliding targets for a unique target.
Beware: Having two different targets that switch off the renaming with the option
no_rename = True
will abort the build file generation.
The following build configuration file:
ex1 = executable('example.bin', 'test.cpp', compiler_opts = '-O1')
ex2 = executable('example.bin', 'test.cpp', compiler_opts = '-O2')
ex3 = executable('example.bin', 'test.cpp', compiler_opts = '-O3')
ex4 = executable('example.bin', 'test.cpp', compiler_opts = '-O2', no_rename = True)
print('hash(ex1) = %s' % ex1.get_hash())
print('hash(ex2) = %s' % ex2.get_hash())
print('hash(ex3) = %s' % ex3.get_hash())
print('hash(ex4) = %s' % ex4.get_hash())
will result (for example in an linux environment) in the generation of three object files named
test_<hash1>.o
, test_<hash2>.o
, test_<hash3>.o
, since there are only three different
settings used during the compilation of test.cpp
.
During the linking step, these object files will generate three binaries named
example.bin
, example_<hash4>.bin
, example_<hash5>.bin
.
Where example.bin
was compiled with the compiler option ‘-O2’. To identify which
target belongs to which hash, the <target_obj>.get_hash()
function can be used.
However it is strongly recommended to always ensure collision free names for executables and shared / static libraries.
BuildSource¶
The build source is the fundamental building block of pyrate. It is modeled by a class BuildSource
,
which can be constructed with the following code:
BuildSource(on_use_inputs = None, on_use_deps = None, on_use_variables = None)
The three arguments on_use_inputs
, on_use_deps
and on_use_variables
specify how a rule belonging
to a build target should react to having the BuildSource as input. Each argument can be a dictionary, where
the key specifies the rule (a rule name string or None
to match any rule) and the value specifies for
on_use_inputs
a list of objects withname
attribute that is given as input arguments for the targeton_use_deps
a list of objects withname
attribute that is specified as dependency of the targeton_use_variables
a dictionary with variables for the target. Probably the most important variable isopts
, which is used to supply options to rules
Examples for different build sources are:
- any string that is given as build input is converted into an
InputFile` - a ``BuildSource
that forwards the specified file name to any rules (usingon_use_inputs
) Externals
- are a type ofBuildSource
that specifyon_use_variables
among other things- all targets are BuildSources as well - so the result of a
shared_library
call can be used to link another target against this libray macro(expr)
- creates a BuildSource that allows to define C/C++ preprocessor macros.
Installing Targets¶
install(target_list)
This function will create install targets in the build file to install the given target / list of targets. In particular an install target will be created that will contain all generated install targets.
Subdirectories¶
include(build_file_list, inherit = False, target_name = None)
This function will read in the given build config file(s). If a directory is given instead of a build config file, pyrate will enter the given directory and use the filebuild.py
if available. The parameterinherit
allows to inheritbasepath_*
andimplicit_*
settings from the current context. The parametertarget_name
allows to specify the name of the alias that allows to build all included targets. By default, this target name is derived from the path given inbuild_file_list
. Current implementation notice - the targets from the included file will be adapted for proper paths and included in the build output of the main file. The goal is to allow very loose coupling between the main project and the subsystem projects so each subsystem can be independently processed without any changes.find_internal(name)
This function allows to retrieve build targets that were created byexecutable
,shared_library
,static_library
andobject_file
. It will match against the user specified name, the installation name (with platform specific extensions) and the build target name (derived from the specifiedbasepath
andbasepath_...
and the installation name). This is in particular useful when trying to specify dependencies one objects included from another file.
Externals¶
Currently the following builtin externals are supported (listed with all possible find_external
arguments):
gcc
- GNU C compilerclang
- LLVM C compilerg++
,gpp
- GNU C++ compilerclang++
,clangpp
- LLVM C++ compilergfortran
- GNU Fortran compilerversion
- specifies required version (eg.version >= 5.2
)std
- language standard version (eg.'c++14'
or'latest'
). A property with the same name allows to also set this value on an existing external (eg.tool['c'].std = 'c90'
).compiler
- name of the executablecompiler_opts
- options that are used during the compilation stage
swig
- The swig package also provides the member functionwrapper
to describe the generation of automated interface codeversion
- specifies required version (eg.version > '3.0.2'
)wrapper(target_language, library_name, interface_filename, libs = [<targets>...], context = None, ...)
-context
allows to specify a different build context, additional keyword parameters are forwarded to the shared_library invokation that creates the wrapper library
link-base
- basic linker tools (usingld
andar
)link-gcc
- calling linker via gcc (usinggcc
andgcc-ar
)link-llvm
- calling linker via llvm (usingclang
andllvm-ar
)link_static
- path to the static linkerlink_static_opts
- options for the static linkerlink_shared
- path to the shared linkerlink_shared_opts
- options for the shared linkerlink_exe
- path to the executable linkerlink_exe_opts
- options for the executable linker
pthread
- posix thread librarystdlibcpp
- GNU C++ librarylibcpp
- LLVM C++ library
The following list contains all builtin externals with a single find_external
parameter version
,
that specifies the required version (eg. version >= 2.6
):
fltk
- FLTK GUI Libraryllvm
- LLVM compiler infrastructure librariesodbc
- Open Database Connectivity middlewareroot
- Library for large scale data analysiswx
- wxWidgets GUI Toolkit
Many more externals are available through the integration with pkg-config
. The full list
of available packages on a system can be queried with:
pkg-config --list-all
All packages listed in that overview can be accessed with the find_external
function.
Toolchains¶
The following toolchains are currently available:
gcc
- the GNU compiler collection This toolchain will activate thegcc
C compiler,g++
C++ compiler and thegfortran
Fortran compiler. Linking will be done withlink-gcc
as driver.version
- requested versionc_std
,c_opts
- control the std and flags of thegcc
externalcpp_std
,cpp_opts
- control the std and flags of thegpp
externalfortran_std
,fortran_opts
- control the std and flags of thegfortran
externallink_shared_opt
,link_exe_opt
- control the linker settings
llvm
- the LLVM Compiler Infrastructure This toolchain will activate theclang
C compiler and theclang++
C++ compiler. Linking will be done with thelink-llvm
package.version
- requested versionc_std
,c_opts
- control the std and flags of theclang
externalcpp_std
,cpp_opts
- control the std and flags of theclang++
externallink_shared_opt
,link_exe_opt
- control the linker settings
Example¶
The basic pyrate build configuration file for a simple C++ project with a single source file producing a single executable looks like this:
executable('test', ['test.cpp'])
A more complicated example is presented in the following code fragment. It demonstrates how to
- change the default compiler toolchain to llvm (clang / clang++),
- define a native static and dynamic library from a set of files selected by wildcards,
- generate several executables accessing to the shared library and
- generate a wrapper library to access the C++ library from python (if swig is available).
use_toolchain('llvm', version >= 3.7, cpp_std = 'c++11', cpp_opts = '-Wall')
lib_files = match('*.cpp -test* -mylib.* -py_foo.cpp')
static_library('libFoo', lib_files, compiler_opts = '-O3')
lib_reference = shared_library('libFoo', lib_files)
python = find_external('python', version > 2)
swig = find_external('swig', version >= 2)
if swig and python:
swig.wrapper('python', 'mylib', 'foo.i', libs = [lib_reference])
for fn in match('test*.cpp'):
executable(fn.replace('.cpp', '.bin'), [fn, lib_reference, find_external('pthread')])
Many more examples with an increasing level of complexity are available in the github repository.
Changelog¶
- 0.2.0 changes
- renamed external packages:
clang
toclang++
,gcc
tog++
- added external packages:
clang
,gcc
,libstdc++
,libc++
,gfortran
,link-base
,link-gcc
,link-llvm
- renamed
compiler
variable totools
, changed to lower case slot names, usingcpp
instead ofC++
- added
toolchain
andfind_toolchain
to set multiple tools at once
- renamed external packages: