The Library Builder (pronounced lbuild) is a BSD licensed Python 3 tool for describing repositories containing modules which can copy or generate a set of files based on the user provided data and options.
lbuild allows splitting up complex code generation projects into smaller modules with configurable options, and provides for their transparent discovery, documentation and dependency management. Each module is written in Python 3 and declares its options and how to generate its content via the Jinja2 templating engine or a file/folder copy.
You can install lbuild via PyPi: pip install lbuild
Projects using lbuild:
The dedicated maintainer of lbuild is @salkinium.
Consider this repository:
$ lbuild discover
Parser(lbuild)
╰── Repository(repo @ ../repo)
├── Option(option) = value in [value, special]
├── Module(repo:module)
│ ├── Option(option) = yes in [yes, no]
│ ├── Module(repo:module:submodule)
│ │ ╰── Option(option) = REQUIRED in [1, 2, 3, 4, 5]
│ ╰── Module(repo:module:submodule2)
╰── Module(modm:module2)lbuild is called by the user with a configuration file which contains the repositories to scan, the modules to include and the options to configure them with:
<library>
<repositories>
<repository><path>../repo/repo.lb</path></repository>
</repositories>
<options>
<option name="repo:option">special</option>
<option name="repo:module:option">3</option>
</options>
<modules>
<module>repo:module</module>
</modules>
</library>The repo.lb file is compiled by lbuild and the two functions init,
prepare are called:
def init(repo):
repo.name = "repo"
repo.add_option(EnumerationOption(name="option",
enumeration=["value", "special"],
default="value"))
def prepare(repo, options):
repo.find_modules_recursive("src")This gives the repository a name and declares a string option. The prepare step
adds all module files in the src/ folder.
Each module.lb file is then compiled by lbuild, and the three functions
init, prepare and build are called:
def init(module):
module.name = ":module"
def prepare(module, options):
if options["repo:option"] == "special":
module.add_option(EnumerationOption(name="option", enumeration=[1, 2, 3, 4, 5]))
return True
return False
def build(env):
env.outbasepath = "repo/module"
env.copy("static.hpp")
for number in range(env["repo:module:option"]):
env.template("template.cpp.in", "template_{}.cpp".format(number + 1))The init step sets the module's name and its parent name. The prepare step
then adds a EnumerationOption and makes the module available, if the repository option
is set to "special". Finally in the build step, a number of files are generated
based on the option's content.
The files are generated at the call-site of lbuild build which would then
look something like this:
$ ls
main.cpp project.xml
$ lbuild build
$ tree
.
├── main.cpp
├── repo
│ ├── module
│ │ ├── static.hpp
│ │ ├── template_1.cpp
│ │ ├── template_2.cpp
│ │ └── template_3.cppThe above example shows a minimal feature set, but lbuild has a few more tricks up its sleeves. Let's have a look at the API in more detail with examples from the modm repository.
Before you can build a project you need to provide a configuration. lbuild aims to make discovery easy from the command line:
$ lbuild --repository ../modm/repo.lb discover
Parser(lbuild)
╰── Repository(modm @ ../modm) modm: a barebone embedded library generator
╰── Option(target) = REQUIRED in [at90can128, at90can32, at90can64, ...This gives you an overview of the repositories and their options. In this case
the modm:target repository option is required, so let's check that out:
$ lbuild -r ../modm/repo.lb discover-options
modm:target = REQUIRED in [at90can128, at90can32, at90can64, at90pwm1, at90pwm161, at90pwm2,
... a really long list ...
stm32l4s9vit, stm32l4s9zij, stm32l4s9zit, stm32l4s9ziy]
Meta-HAL target deviceYou can then choose this repository option and discover the available modules for this specific repository option:
$ lbuild -r ../modm/repo.lb --option modm:target=stm32f407vgt discover
Parser(lbuild)
╰── Repository(modm @ ../modm) modm: a barebone embedded library generator
├── Option(target) = stm32f407vgt in [at90can128, at90can32, at90can64, ...]
├── Configuration(modm:disco-f407vg)
├── Module(modm:board) Board Support Packages
│ ╰── Module(modm:board:disco-f469ni) STM32F469IDISCOVERY
├── Module(modm:build) Build System Generators
│ ├── PathOption(build.path) = build/parent-folder in [String]
│ ├── Option(project.name) = parent-folder in [String]
│ ╰── Module(modm:build:scons) SCons Build Script Generator
│ ├── Option(info.build) = no in [yes, no]
│ ╰── Option(info.git) = Disabled in [Disabled, Info, Info+Status]
├── Module(modm:platform) Platform HAL
│ ├── Module(modm:platform:can) Controller Area Network (CAN)
│ │ ╰── Module(modm:platform:can:1) Instance 1
│ │ ├── Option(buffer.rx) = 32 in [1 .. 32 .. 65534]
│ │ ╰── Option(buffer.tx) = 32 in [1 .. 32 .. 65534]
│ ├── Module(modm:platform:core) ARM Cortex-M Core
│ │ ├── Option(allocator) = newlib in [block, newlib, tlsf]
│ │ ├── Option(main_stack_size) = 3072 in [256 .. 3072 .. 65536]
│ │ ╰── Option(vector_table_location) = rom in [ram, rom]You can now discover all module options in more detail:
$ lbuild -r ../modm/repo.lb -D modm:target=stm32f407vgt discover-options
modm:target = stm32f407vgt in [at90can128, at90can32, at90can64, ...]
Meta-HAL target device
modm:build:build.path = build/parent-folder in [String]
Path to the build folder
modm:build:project.name = parent-folder in [String]
Project name for executableOr check out specific module and option descriptions:
$ lbuild -r ../modm/repo.lb -D modm:target=stm32f407vgt discover -n :build
>> modm:build
# Build System Generators
This parent module defines a common set of functionality that is independent of
the specific build system generator implementation.
>>>> modm:build:project.name [StringOption]
# Project Name
The project name defaults to the folder name you're calling lbuild from.
Value: parent-folder
Inputs: [String]
>>>> modm:build:build.path [StringOption]
# Build Path
The build path is defaulted to `build/{modm:build:project.name}`.
Value: build/parent-folder
Inputs: [String]The complete lbuild command line interface is available with lbuild -h.
Even though lbuild can be configured sorely via the command line, it is
strongly recommended to create a configuration file (default is project.xml)
which lbuild will search for in the current working directory.
<library>
<repositories>
<!-- Declare all your repository locations relative to this file here -->
<repository><path>path/to/repo.lb</path></repository>
<!-- You can also use environment variables in all nodes -->
<repository><path>${PROJECTHOME}/repo2.lb</path></repository>
<!-- You can also search for repository files -->
<glob>ext/**/repo.lb</glob>
</repositories>
<!-- You can also inherit from another configfile. The options you specify
here will be overwritten. -->
<extends>path/to/config.xml</extends>
<!-- A repository may provide aliases for configurations, so that you can
use a string as well, instead of a path. This saves you from knowing
exactly where the configuration file is stored in the repo.
See also `repo.add_configuration(...)`. -->
<extends>repo:name_of_config</extends>
<!-- A configuration alias may also be versioned -->
<extends>repo:name_of_config:specific_version</extends>
<!-- You can declare the *where* the output should be generated, default is cwd -->
<outpath>generated/folder</outpath>
<options>
<!-- Options are treated as key-value pairs -->
<option name="repo:repo_option_name">value</option>
<!-- An option set is the only one allowing multiple values -->
<option name="repo:module:module_option_name">set, options, may, contain, commas</option>
</options>
<modules>
<!-- You only need to declare the modules you are actively using.
The dependencies are automatically resolved by lbuild. -->
<module>repo:module</module>
<module>repo:other_module:submodule</module>
</modules>
</library>On startup, lbuild will search the current working directory upwards for one or more
lbuild.xml files, which if found, are used as the base configuration, inherited
by all other configurations. This is very useful when several projects all
require the same repositories, and you don't want to specify each repository
path for each project.
<library>
<repositories>
<repository><path>path/to/common/repo.lb</path></repository>
</repositories>
<modules>
<module>repo:module-required-by-all</module>
</modules>
</library>In the simplest case your project just <extends> this base config.
<library>
<extends>repo:config-name</extends>
</library>lbuild properly imports the declared repository and modules files, so you can
use everything that Python has to offer.
In addition to importing your required modules, lbuild provides these
global functions and classes for use in all files:
localpath(path): remaps paths relative to the currently executing file.
All paths are already interpreted relative to this file, but you can use this
to be explicit.repopath(path): remaps paths relative to the repository file. You should use
this to reference paths that are not related to your module.listify(obj): turns obj into a list, maps None to empty list.listrify(obj): turns obj into a list of strings, maps None to empty list.uniquify(obj): turns obj into a unique list, maps None to empty list.FileReader(path): reads the contents of a file and turns it into a string.{*}Option(...): classes for describing options, see Options.{*}Query(...): classes for sharing code and data, see Queries.{*}Collector(...): classes for describing metadata sinks, see Collectors.Alias(...): links to other nodes, see Aliases.Configuration(...): links to a configuration inside the repository.lbuild calls these three functions for any repository file:
init(repo): provides name, documentation and other global functionality.prepare(repo, options): adds all module files for this repository.build(env) (optional): only called if at least one module within the
repository is built. It is meant for actions that must be performed for any
module, like generating a global header file, or adding to the include path.# You can use everything Python has to offer
import antigravity
def init(repo):
# You must give your repository a name, and it must be unique within the
# scope of your project as it is used for namespacing all modules
repo.name = "name"
# You can set a repository description here, either as an inline string
repo.description = "Repository Description"
# or as a multi-line string
repo.description = """
Multiline description.
Use whatever markup you want, lbuild treats it all as text.
"""
# or read it from a separate file altogether
repo.description = FileReader("module.md")
# lbuild displays the descriptions as-is, without any modification, however,
# you can set a custom format handler to change this for your repo.
# NOTE: Custom format handlers are applied to all modules and options.
def format_description(node, description):
# in modm there's unit test metadata in HTML comments, let's remove them
description = re.sub(r"\n?<!--.*?-->\n?", "", description, flags=re.S)
# forward this to the default formatter
return node.format_description(node, description)
repo.format_description = format_description
# You can also format the short descriptions for the discover views
def format_short_description(node, description):
# Remove the leading # from the Markdown headers
return node.format_short_description(node, description.replace("#", ""))
repo.format_short_description = format_short_description
# Add ignore patterns for all repository modules
# ignore patterns follow fnmatch rules
repo.add_ignore_patterns("*/*.lb", "*/board.xml")
# Add Jinja2 filters for all repository modules
# NOTE: the filter is namespaced with the repository! {{ "A" | repo.number }} -> 65
repo.add_filter("repo.number", lambda char: ord(char))
# Add an alias for a internal configuration
# NOTE: the configuration is namespaced with the repository! <extends>repo:config</extends>
repo.add_configuration(Configuration(name="config",
description="Special Config",
path="path/to/config.xml")
# You can also add configuration versions
repo.add_configuration(Configuration(name="config2",
description="Versioned Config",
path={"v1": "path/to/config_v1.xml",
"v2": "path/to/config_v2.xml"})
# See Options for more option types
repo.add_option(StringOption(name="option", default="value"))
def prepare(repo, options):
# Access repository options via the `options` resolver
if options["repo:option"] == "value":
# Adds module files directly, or via globbing, all paths relative to this file
repo.add_modules("folder/module.lb", repo.glob("*/*/module.lb"))
# Searches recursively starting at basepath, adding any file that
# fnmatch(`modulefile`), while ignoring fnmatch(`ignore`) patterns
repo.add_modules_recursive(basepath=".", modulefile="*.lb", ignore="*/ignore/patterns/*")
# The build step is optional
def build(env):
# Add the generated src/ folder to the header search path collector
env.collect("::include_path", "src/")
# See module.build(env) for complete feature description.lbuild calls these five functions for any module file:
init(module): provides module name, parent and documentation.prepare(module, options): enables modules, adds options and submodules by
taking the repository options into consideration.validate(env) (optional): validate your inputs before building anything.build(env): generate your library and add metadata to build log.post_build(env, buildlog) (optional): access the build log after the build
step completed.Module files are provided with these additional global classes:
Module: Base class for generated modules.ValidateException: Exception to be raised when the validate(env) step fails.Note that in contrast to a repository, modules must return a boolean from the
prepare(module, options) function, which indicates that the module is available
for the repository option configuration. This allows for modules to "share" a
name, but have completely different implementations.
The validate(env) step is used to validate the input for the build step,
allowing for computations that can fail to raise a ValidateException("reason").
lbuild will collect these exceptions for all modules and display them
together before aborting the build. This step is performed before each build,
and you cannot generate any files in this step, only read the repository's state.
You can manually call this step via the lbuild validate command.
The build(env) step is where the actual file generation happens. Here you can
copy and generate files and folders from Jinja2 templates with the substitutions
of you choice and the configuration of the modules. Each file operation is
appended to a global build log, which you can also explicitly add metadata to.
The post_build(env) step is meant for modules that need to generate
files which receive information from all built modules. The typically use-case
here is generating scripts for build systems, which need to know about what
files were generated and all module's metadata.
def init(module):
# give your module a hierarchical name, the repository name is implicit
module.name = "repo:name"
module.name = ":name" # same as this
# You can set a module description here
module.description = "Description"
module.description = """Multiline"""
module.description = FileReader("module.md")
# modules can have their own formatters, works the same as for repositories
module.format_description = custom_format_description
module.format_short_description = custom_format_short_description
# Add Jinja2 filters for this modules and all submodules
# NOTE: the filter is namespace with the repository! {{ 65 | repo.character }} -> "A"
module.add_filter("repo.character", lambda number: chr(number))
def prepare(module, options):
# Access repository options via the `options` resolver
if options["repo:option"] == "value":
# Returning False from this step disables this module
return False
# modules can depend on other modules
module.depends("repo:module1", ":module2", ":module3:submodule", ...)
# You can add more submodules in files
module.add_submodule("folder/submodule.lb")
# You can generate more modules here. This is useful if you have a lot of
# very similar modules (like instances of hardware peripherals) that you
# don't want to create a module file for each for.
class Instance(Module):
def __init__(self, instance):
self.instance = instance
def init(self, module):
module.name = str(self.instance)
def prepare(self, module, options):
pass
def validate(self, env): # optional
pass
def build(self, env):
pass
def post_build(self, env): # optional
pass
# You can statically create and add these submodules
for index in range(0, 5):
module.add_submodule(Instance(index))
# or make the creation dependent on a repository option
for index in options["repo:instances"]:
module.add_submodule(Instance(index))
# See Options for more option types
module.add_option(StringOption(name="option", default="world"))
def common_operation(args):
"""
You can share any function with other modules.
This is useful to not have to duplicate code across module.lb files.
"""
return args
# See Queries for more query types
module.add_query(Query(name="shared_function", function=common_operation))
# You can collect information from active modules, to use any post_build step
# See Collectors for more collector types
module.add_collector(
PathCollector(name="include_path", description="Global header search paths"))
# Make this module available
return True
# store data computed in validate step for build step.
build_data = None
# The validation step is optional
def validate(env):
# Perform your input validations here
# Access all options
repo_option = env["repo:option"]
defaulted_option = env.get("repo:module:option", default="hello")
# Use proper logging instead of print() please
# env.log.warning(...) and env.log.error(...) also available
env.log.debug("Repo option: '{}'".format(repo_option))
# You can query for options
if env.has_option("repo:module:option") or env.has_module("repo:module"):
env.log.info("Module option: '{}'".format(env["repo:module:option"]))
# Call shared functions from other modules with arguments
shared_function = env.query("repo:module:shared_function")
result = shared_function("argument")
# Or just precomputed properties without arguments
data = env.query("repo:module:shared_property")
# You may also use incomplete queries, see Name Resolution
env.has_module(":module") # instead of repo:module
env.has_option("::option") # repo:module:option
# And use fnmatch queries
# matches any module starting with `mod` and option starting with `name`.
env.has_option(":mod*:name*")
env.has_query("::shared_*")
env.has_collector("::collector")
# Raise a ValidateException if something is wrong
if defaulted_option + repo_option != "hello world":
raise ValidateException("Options are invalid because ...")
# If you do heavy computations here for validation, you can store the
# data in a global variable and reuse this for the build step
global build_data
build_data = defaulted_option * 2
# The build step can do everything the validation step can
# But now you can finally generate files
def build(env):
# Set the output base path, this is relative to the lbuild invocation path
env.outbasepath = "repo/module"
# Copy single files
env.copy("file.hpp")
# Copy single files while renaming them
env.copy("file.hpp", "cool_filename.hpp")
# Relative paths are preserved!!!
env.copy("../file.hpp") # copies to repo/file.hpp
env.copy("../file.hpp", dest="file.hpp") # copies to repo/module/file.hpp
# You can also copy entire folders
env.copy("folder/", dest="renamed/")
# and ignore specific RELATIVE files/folders
env.copy("folder/", ignore=env.ignore_files("*.txt", "this_specific_file.hpp"))
# or ignore specific ABSOLUTE paths
env.copy("folder/", ignore=env.ignore_paths("*/folder/*.txt"))
# You can also copy files out of a .zip or .tar archive
env.extract("archive.zip") # everything inside the archive
env.extract("archive.zip", dest="renamed/") # extract into folder
# You can extract only parts of the archive, like a single file
env.extract("archive.zip", src="https://github.com/modm-io/lbuild/raw/develop/filename.hpp", dest="renamed.hpp")
# or an a single folder somewhere in the archive
env.extract("archive.zip", src="https://github.com/modm-io/lbuild/raw/develop/folder/subfolder", dest="renamed/folder")
# of course, you can ignore files and folders inside the archive too
env.extract("archive.zip", src="https://github.com/modm-io/lbuild/raw/develop/folder", dest="renamed", ignore=env.ignore_files("*.txt"))
# Set the global Jinja2 substitutions dictionary
env.substitutions = {
"hello": "world",
"instances": map(str, env["repo:instances"]),
"build_data": build_data, # from validation step
}
# and generate a file from a template
env.template("template.hpp.in")
# any `.in` postfix is automatically removed, unless you rename it
for instance in env["repo:instances"]:
env.template("template.hpp.in", "template_{}.hpp".format(instance))
# You can explicitly add Jinja2 substitutions and filters
env.template("template.hpp.in",
substitutions={"more": "subs"},
filters={"stringify": lambda i: str(i)})
# Note: these filters are NOT namespaced with the repository name!
# submodules are build first, so you can access the generated files
headers = env.get_generated_local_files(lambda file: file.endswith(".hpp"))
# and use this information for a new template.
env.template("module_header.hpp.in", substitutions={"headers": headers})
# Add values to a collector, all these are type checked
env.collect("::include_path", "repo/must_be_valid_path/", "repo/folder2/")
# The post build step can do everything the build step can,
# but you can't add to the metadata anymore:
# - env.collect() unavailable
# You have access to the entire buildlog up to this point
def post_build(env):
# The absolute path to the lbuild output directory
outpath = env.buildlog.outpath
# All modules that were built
modules = env.buildlog.modules
# All file generation operations that were done
operations = env.buildlog.operations
# All operations per module
operations = env.buildlog.operations_per_module("repo:module")
# iterate over all operations directly
for operation in buildlog:
# Get the module name that generated this file
env.log.info("Module({}) generated the '{}' file"
.format(operation.module, operation.filename))
# You can also get the filename relative to a subfolder in outpath
env.relative_output(operation.filename, "subfolder/")
# or as an absolute path
env.real_output(operation.filename, "subfolder/")
# get all include paths from all active modules
include_paths = env.collector_values("::include_path")lbuild options are mappings from strings to Python objects. Each option must have a unique name within their parent repository or module. If you do not provide a default value, the option is marked as REQUIRED and the project cannot be built without it.
def prepare(module, options):
# Add option to module
option = Option(...)
module.add_option(option)
def build(env):
# Check if options exist
exists = env.has_option(":module:option")
# Access option value or use default if option doesn't exist
value = env.get(":module:option", default="value")
# Access option values, this may raise an exception if option doesn't exist
value = env[":module:option"]If your option requires a unique set of input values, you can tell lbuild to
wrap the option into a set using module.add_set_option():
def prepare(module, options):
# Add an option, but allow a set of unique values as input and output
module.add_set_option(option)
def build(env):
# a unique set of option values is returned here
for value in env[":module:option"]:
print(value)Option sets are declared as comma-separated strings, so that inheriting
configurations or passing option values via CLI can overwrite these sets.
A StringOption cannot be wrapped into a set for this reasons, however, it's
easy to split your string value in Python exactly how you want.
<!-- All comma separated values are validated by the option -->
<option name=":module:set-option">value, 1, obj</option>If you want to preserve duplicates to count the number of inputs, use a list
option module.add_list_option():
def prepare(module, options):
# Add an option, but allow a list of values as input and output
module.add_list_option(option)
def build(env):
# a list of option values is returned here
value_count = env[":module:option"].count("value")Options can have a dependency handler which is called when the project configuration is merged into the module options. It will give you the chosen input value and you can return a number of module dependencies.
def add_option_dependencies(value):
if special_condition(value):
# return single dependency
return "repo:module"
if other_special_condition(value):
# return multiple dependencies
return [":module1", ":module2"]
# No additional dependencies
return NoneThis is the most generic option, allowing to input any string.
You may, however, provide your own validator that may raise a ValueError
if the input string does not match your expectations.
You may also pass a transformation function to convert the option value.
The string is passed unmodified from the configuration to the module and the
dependency handler.
def validate_string(string):
if "please" not in string:
raise ValueError("Input does not contain the magic word!")
def transform_string(string):
return string.lower()
option = StringOption(name="option-name",
description="inline", # or FileReader("file.md")
default="default string",
validate=validate_string,
transform=transform_string,
dependencies=add_option_dependencies)This option operates on strings, but additionally validates them to be syntactically valid paths, so the filesystem accepts these strings as valid arguments to path operations. This option does not check if the path exists, or if it can be created, just if the string is properly formatted.
Since an empty string is not a valid path, but it can be useful to allow an
empty string as an input value to encode a special case (like a "disable" value),
you may set empty_ok=True to tell the path validation to ignore empty strings.
By default, the path input is not modified and must be correctly interpreted in
the context of the module that uses it (usually relocated to the output path).
However, if you want to input an existing path you should set absolute=True,
so that lbuild can relocate the relative path declared in the config files
to an absolute path, which is indepented of the CWD.
This is particularly useful if you declare paths in config files that are not
located at the project root, like options inherited from multiple lbuild.xml.
option = PathOption(name="option-name",
description="path",
default="path/to/folder/or/file",
empty_ok=False, # is an empty path considered valid?
absolute=False, # is the path relative to the config file?
validate=validate_path,
dependencies=add_option_dependencies)This option maps strings from true, yes, 1, enable to bool(True) and
false, no, 0, disable to bool(False). You can extend this list with a
custom transform handler. The dependency handler is passed this bool value.
def transform_boolean(string):
if string == 'y': return True;
if string == 'n': return False;
return string # hand over to built-in conversion
option = BooleanOption(name="option-name",
description="boolean",
default=True,
transform=transform_boolean,
dependencies=add_option_dependencies)This option allows a number from [-Inf, +Inf]. You can limit this to the
range [minimum, maximum].
The values can be specified directly as numeric value or as a string, which is
interpreted using the eval() function, so that you can describe values as more
intuitive formulas when necessary.
You can also suffix numbers with the SI multipliers K, M, G, T, Ki,
Mi, Gi, and Ti to simplify formulas even further.
Note that you should use strings to specify precise floating point values such
as "1/3". The validation and dependency handlers are passed a numeric value.
option = NumericOption(name="option-name",
description="numeric",
minimum=0,
maximum="5Mi*2",
default="1K",
validate=validate_number,
dependencies=add_option_dependencies)This option maps a string to any generic Python object. You can provide a list, set, tuple or range, the only limitation is that the objects must be convertible to a string for unique identification. If this is not possible, you can provide a dictionary with a manual mapping from string to object. The dependency handler is passed the string value.
option = EnumerationOption(name="option-name",
description="enumeration",
# must be implicitly convertible to string!
enumeration=["value", 1, obj],
# or use a dictionary explicitly
enumeration={"value": "value", "1": 1, "obj": obj},
default="1",
dependencies=add_option_dependencies)It is sometimes necessary to share code and data between lbuild modules, which can be difficult when they are split across files and repositories. Queries allow you to share functions and computed properties with other modules using the global name resolution system.
def prepare(module, options):
# Add queries to module
query = Query(...)
module.add_query(query)
def build(env):
exists = env.has_query(":module:query")
# Access query value or use default if query doesn't exist
data = env.query(":module:query", default="value")Note that queries must be stateless (aka. a pure function), since module build order is not guaranteed. You must enforce this property yourself.
You can discover all the available queries in your repository using
lbuild discover --developer.
This wraps any callable object into a query. By default the name is taken from the object's name, however, you may overwrite this. Note that when using a lambda function, you must provide a name. The description is taken from the objects docstring.
def shared_function(args):
"""
Describe what this query does.
:param args: what does it need?
:returns: what does it return?
"""
return args
query = Query(function=shared_function)
query = Query(name="different_name",
function=shared_function)This query's result is computed only once on demand and then cached.
The data must be returned from a factory function that gets passed the environment of the first module to access this query. The return value is then cached for all further accesses. This allows you to lazily compute your shared properties only once and only if accessed by any module.
def factory(env):
"""
Describe what this query is about, but don't document the `env` argument.
:returns: an immutable object
"""
# You can read the build environment, but cannot modify it here
value = env["repo:module:option"]
# This return data is cached, so this function is only called once.
return {"key": value}
query = EnvironmentQuery(name="name",
factory=factory)The post-build step has access to the build log containing the list of modules that were built and what files they generated. However, these modules also need to pass additional data to the post-build steps, so that this information can be computed locally.
lbuild allows each module to declare what metadata it wants using a collector, which is given a name, description and optional limitations depending on type. In the build step, each module may add values to this collector, which the post-build steps then can access.
def prepare(module, options):
# Add a collector to module
collector = Collector(...)
module.add_collector(collector)
def build(env):
exists = env.has_collector(":module:collector")
# Add values to this collector
env.collect(":module:collector", "value1", "value2", "value3")
def post_build(env):
# Get all unique values from all operations
unique_values = env.collector_values(":module:collector")
# get all values from all operations, even duplicates!
all_values = env.collector_values(":module:collector", unique=False)Note that the ordering of values is preserved only relative to the order they
were added within a module and only if accessing them non-uniquely!
The above example will preserve the order of value1, value2 and value3,
only if the values are accessed not uniquely and only relative to each other.
When you add values to a collector, the current operation is recorded, consisting out of the current module, but you may also explicitly set this to a set of file operations:
def build(env):
operation = env.copy("file.hpp")
# Add values to this collector for the file operation
env.collect(":module:collector", "values", operations=operation)
# The return value from a file operation is actually a set of operations
operations = env.copy("folder1/")
# So you can extend this set for multiple file operations
operations |= env.copy("folder2/")
# And then filter this set of operations
operations = filter(lambda op: op.filename.endswith(".txt"), operations)
# Only add this metadata to .txt files
env.collect(":module:collector", "txt-file-values", operations=operations)
# A file operation object has these properties:
operation.module # full module name, this is always available
operation.repository # repository name, always available
operation.has_filename # Some operations are specific to files
operation.filename # The generated filename relative to outpath
def post_build(env):
# You can use these operation properties to filter the collector values
txt_filter = lambda op: op.repository == "repo" and op.filename.endswith(".txt")
unique_txt_values = env.collector_values(":module:collector", filterfunc=txt_filter)
# May contain duplicate values!
all_txt_values = env.collector_values(":module:collector", filterfunc=txt_filter, unique=False)If you have very special requirements for the ordering values (for example when collecting compile flags), consider iterating over the collectors items manually, and possibly de-duplicating and reordering the values yourself.
def post_build(env):
# Get the collector, may return None if collector does not exist!
collector = env.collector(":module:collector")
if collector is not None:
for operation, values in collector.items():
# values is a list and may contain duplicates
print(operation.module, values)
if operation.has_filename: # not all operations have filenames!
print(operation.filename)Note that collector values that were added by a module without explicit operations do not have filename, only module names!
Collectors are implemented using the same type-safe mechanisms as Options, the only differences are the lack of dependency handlers and default values, since you can add default values in the modules build step.
You may add collector values via the project configuration. However, since these collector values cannot be overwritten by inheriting configurations use this with care.
<library>
<collectors>
<collect name="repo:collector_name">value</collect>
<collect name="repo:collector_name">value2</collect>
</collectors>
</library>You can discover all the available collectors in your repository using
lbuild discover --developer.
This collector allows you to collect callable objects, that the post-build step can execute. This can be useful for providing specializations to the post-build module without it needing to know how they work.
collector = CallableCollector(name="collector-name",
description="callable")See StringOption for documentation.
collector = StringCollector(name="collector-name",
description="string",
validate=validate_function)See PathOption for documentation.
collector = PathCollector(name="collector-name",
description="path",
empty_ok=False,
absolute=False)See BooleanOption for documentation.
collector = BooleanCollector(name="collector-name",
description="boolean")See NumericOption for documentation.
collector = NumericCollector(name="collector-name",
description="numeric",
minimum=0,
maximum=100)See EnumerationOption for documentation.
collector = EnumerationCollector(name="collector-name",
description="enumeration",
enumeration=enumeration)lbuild aliases are mappings from one lbuild node to another. They are useful for gracefully dealing with renaming or moving nodes in your lbuild module tree. Aliases will print a warning when accessed showing the alias description. Each alias must have a unique name within their parent repository or module.
Aliases can be used for any type of node that you want forwarded. You can also add aliases that do not have a destination and will raise an exception with the alias description. This allows you to remove lbuild nodes while providing details for a workaround.
def prepare(module, options):
# Move option in this module
module.add_module(Option(name="option"))
# Forward the old option to the new option
module.add_alias(Alias(name="option-alias",
destination="option",
description="Renamed for clarity."))
# Instead of silently failing, you can provide a detailed description
# about why the node was removed and what the workaround is.
module.add_alias(Alias(name="removed-alias",
description="Removed. Workaround: ..."))
# You alias any type to any other node.
module.add_alias(Alias(name="submodule-alias",
destination=":other-module:submodule"
description="Removed. Workaround: ..."))
def build(env):
# Will show a warning (once) that the alias has been moved
exists = env.has_option(":module:option-alias")
# Accesses :module:option instead
value = env[":module:option-alias"]
# This will raise an exception with the alias description
value = env[":module:removed-alias"]
# will check for :other-module:submodule instead
value = env.has_module[":module:submodule-alias"]lbuild uses the Jinja2 template engine with the following global configuration:
%% statement.%# comment.jinja2.ext.do.time: strftime("%d %b %Y, %H:%M:%S")options: an option resolver in the context of the current module.lbuild manages repositories, modules and options in a tree structure and
serializes identification into unique string using : as hierarchy delimiters.
Any identifier provided via the command line, configuration, repository or
module files use the same resolver, which allows using partially-qualified
identifiers. In addition, globbing for multiple identifiers using fnmatch
semantics is supported.
The following rules for resolving identifiers apply:
repo:module:option.*:m.dule:opt*.* wildcarts for entire hierarchies can be ommitted: ::option:**, which globs for everything below the current
hierarchy level: repo:** selects all in repo, repo:module:** all in
repo:module, etc.::option
may be unique within the context of :module, but not within the entire
project.option within the context of :module will resolve to
:module:option.Partial identifiers were introduced to reduce verbosity and aid refactoring, it is therefore recommended to:
lbuild executes in this order:
repository:init()repository:prepare(repo-options)module:init()module:prepare(repo-options)module:validate(env) submodules-first, optionalmodule:build(env) submodules-firstrepo:build(env): optionalmodule:post_build(env): submodules-first, optional