bazel/node_modules.bzl

"""Utilities for working with node_modules."""

def node_module_tar(name, package, package_dir = "", owner = "0.0", mode = None):
    """Creates a target which packages the given node module into a tarball.

    Args:
        name: Name of the rule to create.
        package: Name of the node_module directory to package.
        package_dir: Optional, directory prefix to place the contents inside
            the tarball.
        owner: uid and gid of the owner for the files, eg. "2000.2000".
        mode: permissions bits for the files, eg. "755", or "a+x", or None to
            use default.
    """
    uid, gid = owner.split(".")

    # TODO(borenet): Can/should we use `tar` provided by rules_pkg?
    cmd = """
PWD="$$(pwd)"
mkdir -p tar/node_modules

# Find python3.
PYTHON=""
for path in $(locations @python_3_11//:py3_runtime); do
    if [[ "$$path" == *"/bin/python3" ]]; then
        PYTHON="$$path"
        break
    fi
done

# Run the script to strip all but the desired package from our package.json and
# package-lock.json files.
$$PYTHON $(execpath //bazel:strip-package-lock.py) --input=. --output=./tar --package={package}

NPM="$$PWD/$(execpath @nodejs//:npm_bin)"
export PATH="$$PWD/$$(dirname $(execpath @nodejs//:node_bin)):$$PWD/$$(dirname $$NPM):$$PATH"

# Install the package and its dependencies.
export PUPPETEER_SKIP_DOWNLOAD=1
NPM_CACHE="$$PWD/.npm-cache"
$$NPM ci --cache=$$NPM_CACHE --prefix=$$PWD/tar

# Because we used our own package.json/package-lock.json, the package in
# question is not the "main" package and is therefore inside the node_modules
# directory. "Hoist" it up a level.
cp -rL ./tar/node_modules/{package}/* ./tar
rm -rf ./tar/node_modules/{package}

# Package the resulting directory.
tar -chf $@ --owner={uid} --group={gid} --transform 's,tar,{package_dir},' {mode_flag} tar
""".format(
        package_dir = package_dir,
        uid = uid,
        gid = gid,
        mode_flag = "--mode=%s" % mode if mode else "",
        package = package,
    )

    native.genrule(
        name = name,
        srcs = ["//:package.json", "//:package-lock.json"],
        outs = [package + ".tar"],
        cmd = cmd,
        tools = [
            "@nodejs//:node_bin",
            "@nodejs//:npm_bin",
            "@nodejs//:npm_files",
            "@python_3_11//:py3_runtime",
            "//bazel:strip-package-lock.py",
        ],
        visibility = ["//visibility:public"],
    )