4c9c79e9f5
This contains significant rebase / merge / testing work by Naut <lbrynaut@protonmail.com>, Anthony Fieroni <bvbfan@abv.bg> and Brannon King <countprimes@gmail.com>.
53 lines
2.5 KiB
Markdown
53 lines
2.5 KiB
Markdown
This is a system of building and caching dependencies necessary for building Bitcoin.
|
|
There are several features that make it different from most similar systems:
|
|
|
|
### It is designed to be builder and host agnostic
|
|
|
|
In theory, binaries for any target OS/architecture can be created, from a
|
|
builder running any OS/architecture. In practice, build-side tools must be
|
|
specified when the defaults don't fit, and packages must be amended to work
|
|
on new hosts. For now, a build architecture of x86_64 is assumed, either on
|
|
Linux or OSX.
|
|
|
|
### No reliance on timestamps
|
|
|
|
File presence is used to determine what needs to be built. This makes the
|
|
results distributable and easily digestable by automated builders.
|
|
|
|
### Each build only has its specified dependencies available at build-time.
|
|
|
|
For each build, the sysroot is wiped and the (recursive) dependencies are
|
|
installed. This makes each build deterministic, since there will never be any
|
|
unknown files available to cause side-effects.
|
|
|
|
### Each package is cached and only rebuilt as needed.
|
|
|
|
Before building, a unique build-id is generated for each package. This id
|
|
consists of a hash of all files used to build the package (Makefiles, packages,
|
|
etc), and as well as a hash of the same data for each recursive dependency. If
|
|
any portion of a package's build recipe changes, it will be rebuilt as well as
|
|
any other package that depends on it. If any of the main makefiles (Makefile,
|
|
funcs.mk, etc) are changed, all packages will be rebuilt. After building, the
|
|
results are cached into a tarball that can be re-used and distributed.
|
|
|
|
### Package build results are (relatively) deterministic.
|
|
|
|
Each package is configured and patched so that it will yield the same
|
|
build-results with each consequent build, within a reasonable set of
|
|
constraints. Some things like timestamp insertion are unavoidable, and are
|
|
beyond the scope of this system. Additionally, the toolchain itself must be
|
|
capable of deterministic results. When revisions are properly bumped, a cached
|
|
build should represent an exact single payload.
|
|
|
|
### Sources are fetched and verified automatically
|
|
|
|
Each package must define its source location and checksum. The build will fail
|
|
if the fetched source does not match. Sources may be pre-seeded and/or cached
|
|
as desired.
|
|
|
|
### Self-cleaning
|
|
|
|
Build and staging dirs are wiped after use, and any previous version of a
|
|
cached result is removed following a successful build. Automated builders
|
|
should be able to build each revision and store the results with no further
|
|
intervention.
|