Allow use of third party crates with bzlmod.

crate_universe/extension.bzl

@@ -0,0 +1,192 @@
+"""Module extension for generating third-party crates for use in bazel."""
+
+load("@bazel_tools//tools/build_defs/repo:git.bzl", "new_git_repository")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+load("//crate_universe:defs.bzl", _crate_universe_crate = "crate")
+load("//crate_universe/private:crates_vendor.bzl", "CRATES_VENDOR_ATTRS", "generate_config_file", "generate_splicing_manifest")
+load("//crate_universe/private:generate_utils.bzl", "render_config")
+load("//crate_universe/private/module_extensions:cargo_bazel_bootstrap.bzl", "get_cargo_bazel_runner")
+
+def _generate_repo_impl(repo_ctx):
+    for path, contents in repo_ctx.attr.contents.items():
+        repo_ctx.file(path, contents)
+
+_generate_repo = repository_rule(
+    implementation = _generate_repo_impl,
+    attrs = dict(
+        contents = attr.string_dict(mandatory = True),
+    ),
+)
+
+def _generate_hub_and_spokes(module_ctx, cargo_bazel, cfg):
+    cargo_lockfile = module_ctx.path(cfg.cargo_lockfile)
+    tag_path = module_ctx.path(cfg.name)
+
+    rendering_config = json.decode(render_config(
+        regen_command = "Run 'cargo update [--workspace]'",
+    ))
+    config_file = tag_path.get_child("config.json")
+    module_ctx.file(
+        config_file,
+        executable = False,
+        content = generate_config_file(
+            module_ctx,
+            mode = "remote",
+            annotations = {},
+            generate_build_scripts = cfg.generate_build_scripts,
+            supported_platform_triples = cfg.supported_platform_triples,
+            generate_target_compatible_with = True,
+            repository_name = cfg.name,
+            output_pkg = cfg.name,
+            workspace_name = cfg.name,
+            generate_binaries = cfg.generate_binaries,
+            render_config = rendering_config,
+        ),
+    )
+
+    manifests = {module_ctx.path(m): m for m in cfg.manifests}
+    splicing_manifest = tag_path.get_child("splicing_manifest.json")
+    module_ctx.file(
+        splicing_manifest,
+        executable = False,
+        content = generate_splicing_manifest(
+            packages = {},
+            splicing_config = "",
+            cargo_config = cfg.cargo_config,
+            manifests = {str(k): str(v) for k, v in manifests.items()},
+            manifest_to_path = module_ctx.path,
+        ),
+    )
+
+    splicing_output_dir = tag_path.get_child("splicing-output")
+    cargo_bazel([
+        "splice",
+        "--output-dir",
+        splicing_output_dir,
+        "--config",
+        config_file,
+        "--splicing-manifest",
+        splicing_manifest,
+        "--cargo-lockfile",
+        cargo_lockfile,
+    ])
+
+    # Create a lockfile, since we need to parse it to generate spoke
+    # repos.
+    lockfile_path = tag_path.get_child("lockfile.json")
+    module_ctx.file(lockfile_path, "")
+
+    cargo_bazel([
+        "generate",
+        "--cargo-lockfile",
+        cargo_lockfile,
+        "--config",
+        config_file,
+        "--splicing-manifest",
+        splicing_manifest,
+        "--repository-dir",
+        tag_path,
+        "--metadata",
+        splicing_output_dir.get_child("metadata.json"),
+        "--repin",
+        "--lockfile",
+        lockfile_path,
+    ])
+
+    crates_dir = tag_path.get_child(cfg.name)
+    _generate_repo(
+        name = cfg.name,
+        contents = {
+            "BUILD.bazel": module_ctx.read(crates_dir.get_child("BUILD.bazel")),
+        },
+    )
+
+    contents = json.decode(module_ctx.read(lockfile_path))
+
+    for crate in contents["crates"].values():
+        repo = crate["repository"]
+        if repo == None:
+            continue
+        name = crate["name"]
+        version = crate["version"]
+
+        # "+" isn't valid in a repo name.
+        crate_repo_name = "{repo_name}__{name}-{version}".format(
+            repo_name = cfg.name,
+            name = name,
+            version = version.replace("+", "-"),
+        )
+
+        build_file_content = module_ctx.read(crates_dir.get_child("BUILD.%s-%s.bazel" % (name, version)))
+        if "Http" in repo:
+            # Replicates functionality in repo_http.j2.
+            repo = repo["Http"]
+            http_archive(
+                name = crate_repo_name,
+                patch_args = repo.get("patch_args", None),
+                patch_tool = repo.get("patch_tool", None),
+                patches = repo.get("patches", None),
+                remote_patch_strip = 1,
+                sha256 = repo.get("sha256", None),
+                type = "tar.gz",
+                urls = [repo["url"]],
+                strip_prefix = "%s-%s" % (crate["name"], crate["version"]),
+                build_file_content = build_file_content,
+            )
+        elif "Git" in repo:
+            # Replicates functionality in repo_git.j2
+            repo = repo["Git"]
+            kwargs = {}
+            for k, v in repo["commitish"].items():
+                if k == "Rev":
+                    kwargs["commit"] = v
+                else:
+                    kwargs[k.lower()] = v
+            new_git_repository(
+                name = crate_repo_name,
+                init_submodules = True,
+                patch_args = repo.get("patch_args", None),
+                patch_tool = repo.get("patch_tool", None),
+                patches = repo.get("patches", None),
+                shallow_since = repo.get("shallow_since", None),
+                remote = repo["remote"],
+                build_file_content = build_file_content,
+                strip_prefix = repo.get("strip_prefix", None),
+                **kwargs
+            )
+        else:
+            fail("Invalid repo: expected Http or Git to exist for crate %s-%s, got %s" % (name, version, repo))
+
+def _crate_impl(module_ctx):
+    cargo_bazel = get_cargo_bazel_runner(module_ctx)
+    all_repos = []
+    for mod in module_ctx.modules:
+        local_repos = []
+        for cfg in mod.tags.from_cargo:
+            if cfg.name in local_repos:
+                fail("Defined two crate universes with the same name in the same MODULE.bazel file. Use the name tag to give them different names.")
+            elif cfg.name in all_repos:
+                fail("Defined two crate universes with the same name in different MODULE.bazel files. Either give one a different name, or use use_extension(isolate=True)")
+            _generate_hub_and_spokes(module_ctx, cargo_bazel, cfg)
+            all_repos.append(cfg.name)
+            local_repos.append(cfg.name)
+
+_from_cargo = tag_class(
+    doc = "Generates a repo @crates from a Cargo.toml / Cargo.lock pair",
+    attrs = dict(
+        name = attr.string(doc = "The name of the repo to generate", default = "crates"),
+        cargo_lockfile = CRATES_VENDOR_ATTRS["cargo_lockfile"],
+        manifests = CRATES_VENDOR_ATTRS["manifests"],
+        cargo_config = CRATES_VENDOR_ATTRS["cargo_config"],
+        generate_binaries = CRATES_VENDOR_ATTRS["generate_binaries"],
+        generate_build_scripts = CRATES_VENDOR_ATTRS["generate_build_scripts"],
+        supported_platform_triples = CRATES_VENDOR_ATTRS["supported_platform_triples"],
+    ),
+)
+
+crate = module_extension(
+    implementation = _crate_impl,
+    tag_classes = dict(
+        from_cargo = _from_cargo,
+    ),
+)