Files
eagle0/ci/jar_split.bzl

60 lines
2.1 KiB
Python

"""Split a JVM binary's runtime classpath into first-party and third-party jar sets.
This exists so the Docker image can place rarely-changing third-party jars in a
lower OCI layer and frequently-changing first-party jars in a small top layer,
so most pushes only re-upload the small layer.
"""
load("@rules_java//java/common:java_info.bzl", "JavaInfo")
def _unique_name(jar):
# short_path is unique per jar and stable across commits (it depends only on
# the jar's own package/coordinate, not on unrelated targets), so the deps
# layer's tar entries stay byte-identical and its blob digest stays cached.
path = jar.short_path
if path.startswith("../"):
path = path[3:]
return path.replace("+", "_").replace("/", "_").replace("~", "_")
def _impl(ctx):
info = ctx.attr.binary[JavaInfo]
app = []
deps = []
seen = {}
for jar in sorted(info.transitive_runtime_jars.to_list(), key = lambda f: f.path):
workspace = jar.owner.workspace_name if jar.owner else ""
bucket = "app" if workspace == "" else "deps"
out_name = _unique_name(jar)
key = bucket + "/" + out_name
if key in seen:
fail("jar_split: duplicate output name %r for %s and %s" % (
key,
seen[key],
jar.path,
))
seen[key] = jar.path
link = ctx.actions.declare_file(ctx.label.name + "/" + key)
ctx.actions.symlink(output = link, target_file = jar)
(app if bucket == "app" else deps).append(link)
return [
DefaultInfo(files = depset(app + deps)),
OutputGroupInfo(app = depset(app), deps = depset(deps)),
]
jar_split = rule(
implementation = _impl,
doc = "Partitions a JVM binary's transitive runtime jars into 'app' " +
"(first-party, empty workspace) and 'deps' (third-party) output groups.",
attrs = {
"binary": attr.label(
mandatory = True,
providers = [[JavaInfo]],
doc = "A jvm binary/library target whose runtime classpath to split.",
),
},
)