Builtin public data
Elements can provide public data which can be read by other elements later in the pipeline, the format for exposing public data on a given element is described here.
Any element may use public data for whatever purpose it wants, but
BuildStream has some built-in expectations of public data, which resides
completely in the bst
domain.
In this section we will describe the public data in the bst
domain.
Integration commands
# Specify some integration commands
public:
bst:
integration-commands:
- /usr/bin/update-fancy-feature-cache
The built-in integration-commands
list indicates that depending elements
should run this set of commands before expecting the staged runtime environment
to be functional.
Typical cases for this include running ldconfig
at the base of a pipeline,
or running commands to update various system caches.
Integration commands of a given element are automatically run by the
Element.integrate()
method
and are used by various plugins.
Notably the BuildElement
derived classes
will always integrate the build dependencies after staging and before running
any build commands.
Split rules
# Specify some split rules
public:
bst:
split-rules:
runtime:
- |
%{bindir}/*
- |
%{sbindir}/*
- |
%{libexecdir}/*
- |
%{libdir}/lib*.so*
Split rules indicate how the output of an element can be categorized into domains.
The split-rules
domains are used by the
Element.stage_artifact()
method when deciding what domains of an artifact should be staged.
The strings listed in each domain are first substituted with the
variables in context of the given element, and
then applied as a glob style match, as understood by
utils.glob()
This is used for creating compositions with the compose
element and can be used by other deployment related elements for the purpose of
splitting element artifacts into separate packages.
Overlap whitelist
The overlap whitelist indicates which files this element is allowed to overlap over other elements when staged together with other elements.
Each item in the overlap whitelist has substitutions applied from
variables, and is then applied as a glob-style match
(i.e. utils.glob()
).
public:
bst:
overlap-whitelist:
- |
%{sysconfdir}/*
- |
/etc/fontcache