refactor: centralize all of the deb_import functionality in deb_impor…

…t.bzl

Refactor the package repo templates into their own methods and massively
cleanup the `for`-loop in `_deb_package_index_impl`.

IMHO overall now there's a much better and clear separation of concerns
between the "index repo" (`apt/private/index.bzl`) and the "package
repos" (`apt/private/deb_import.bzl`).

apt/extensions.bzl

@@ -48,7 +48,7 @@ def _distroless_extension(module_ctx):
                 name = install.name,
                 lock = install.lock,
                 lock_content = lockf.as_json(),
-                package_template = install.package_template,
+                package_arch_build_template = install.package_arch_build_template,
             )
 
             if mod.is_root:
@@ -74,7 +74,7 @@ install = tag_class(attrs = {
         doc = """Whether dependencies of dependencies should be resolved and added to the lockfile.""",
         default = True,
     ),
-    "package_template": attr.label(doc = "(EXPERIMENTAL!) a template file for generated BUILD files."),
+    "package_arch_build_template": attr.label(doc = "(EXPERIMENTAL!) a template file for the generated package BUILD files per architecture."),
 })
 
 apt = module_extension(

apt/index.bzl

@@ -8,7 +8,7 @@ def deb_index(
         manifest,
         lock = None,
         nolock = False,
-        package_template = None,
+        package_arch_build_template = None,
         resolve_transitive = True):
     """A convience repository macro for apt rules.
 
@@ -81,7 +81,7 @@ def deb_index(
         manifest: label to a `manifest.yaml`
         lock: label to a `lock.json`
         nolock: bool, set to True if you explicitly want to run without a lock and avoid the DEBUG messages.
-        package_template: (EXPERIMENTAL!) a template file for generated BUILD files.
+        package_arch_build_template: (EXPERIMENTAL!) a template file for the generated package BUILD files per architecture.
           Available template replacement keys are: `{target_name}`, `{deps}`, `{urls}`, `{name}`, `{arch}`, `{sha256}`, `{repo_name}`
         resolve_transitive: whether dependencies of dependencies should be resolved and added to the lockfile.
     """
@@ -100,5 +100,5 @@ def deb_index(
     _deb_package_index(
         name = name,
         lock = lock if lock else "@" + name + "_resolve//:lock.json",
-        package_template = package_template,
+        package_arch_build_template = package_arch_build_template,
     )

apt/private/BUILD.bazel

@@ -4,7 +4,7 @@ exports_files([
     "dpkg_statusd.sh",
     "dpkg_status.sh",
     "copy.sh.tmpl",
-    "package.BUILD.tmpl",
+    "package_arch.BUILD.tmpl",
 ])
 
 bzl_library(

apt/private/deb_import.bzl

@@ -3,7 +3,6 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load(":util.bzl", "util")
 
-# BUILD.bazel template
 _DEB_IMPORT_BUILD_TMPL = '''
 genrule(
     name = "data",
@@ -62,8 +61,67 @@ def make_deb_import_key(repo_name, package):
         util.sanitize(package.version),
     )
 
-def deb_import(**kwargs):
+def deb_import(name, url, sha256):
     http_archive(
+        name = name,
+        url = url,
+        sha256 = sha256,
         build_file_content = _DEB_IMPORT_BUILD_TMPL,
-        **kwargs
+    )
+
+def _deb_import_tmpl(repo_name, package):
+    deb_import_key = make_deb_import_key(repo_name, package)
+
+    return '''\
+    deb_import(
+        name = "{name}",
+        url = "{url}",
+        sha256 = "{sha256}",
+    )
+'''.format(name = deb_import_key, url = package.url, sha256 = package.sha256)
+
+def deb_packages(repo_name, packages):
+    deb_imports = [
+        _deb_import_tmpl(repo_name, package)
+        for architectures in packages.values()
+        for package in architectures.values()
+    ]
+
+    return '''\
+"""Generated by rules_distroless. DO NOT EDIT."""
+load("@rules_distroless//apt/private:deb_import.bzl", "deb_import")
+
+# buildifier: disable=function-docstring
+def {repo_name}_packages():
+{deb_imports}
+'''.format(
+        repo_name = repo_name,
+        deb_imports = "\n".join(deb_imports) if deb_imports else "    pass",
+    )
+
+def package_arch_build(package, repo_prefix, repo_name, arch_template):
+    def deps_str(dependencies, arch, depth):
+        return ("\n" + " " * depth).join([
+            '"//%s/%s",' % (dep.name, arch)
+            for dep in dependencies
+        ])
+
+    deb_import_key = make_deb_import_key(repo_name, package)
+
+    deps = '[":data"]'
+    if package.dependencies:
+        deps += """ + [
+        {deps}
+    ]""".format(deps = deps_str(package.dependencies, package.arch, 8))
+    deps += ","
+
+    return arch_template.format(
+        target_name = package.arch,
+        src = '"@%s%s//:data"' % (repo_prefix, deb_import_key),
+        deps = deps,
+        urls = [package.url],
+        name = package.name,
+        arch = package.arch,
+        sha256 = package.sha256,
+        repo_name = "%s%s" % (repo_prefix, deb_import_key),
     )

apt/private/index.bzl

@@ -1,26 +1,8 @@
 "apt-get"
 
-load(":deb_import.bzl", "make_deb_import_key")
+load(":deb_import.bzl", "deb_packages", "package_arch_build")
 load(":lockfile.bzl", "lockfile")
 
-# header template for packages.bzl file
-_DEB_IMPORT_HEADER_TMPL = '''\
-"""Generated by rules_distroless. DO NOT EDIT."""
-load("@rules_distroless//apt/private:deb_import.bzl", "deb_import")
-
-# buildifier: disable=function-docstring
-def {}_packages():
-'''
-
-# deb_import template for packages.bzl file
-_DEB_IMPORT_TMPL = '''\
-    deb_import(
-        name = "{name}",
-        urls = ["{urls}"],
-        sha256 = "{sha256}",
-    )
-'''
-
 _BUILD_TMPL = """\
 exports_files(glob(['packages.bzl']))
 
@@ -31,52 +13,33 @@ alias(
 """
 
 def _deb_package_index_impl(rctx):
-    lock_content = rctx.attr.lock_content
-    package_template = rctx.read(rctx.attr.package_template)
-    lockf = lockfile.from_json(rctx, lock_content if lock_content else rctx.read(rctx.attr.lock))
-
-    package_defs = []
-
-    if not lock_content:
-        package_defs = [_DEB_IMPORT_HEADER_TMPL.format(rctx.attr.name)]
+    lockf = lockfile.from_json(
+        rctx,
+        rctx.attr.lock_content or rctx.read(rctx.attr.lock),
+    )
+    lockf.write("lock.json")
 
-        if not lockf.packages:
-            package_defs.append("   pass")
+    repo_prefix = "@" if rctx.attr.lock_content else ""
+    repo_name = rctx.attr.name
 
     for architectures in lockf.packages.values():
         for package in architectures.values():
-            deb_import_key = make_deb_import_key(rctx.attr.name, package)
-
-            if not lock_content:
-                package_defs.append(
-                    _DEB_IMPORT_TMPL.format(
-                        name = deb_import_key,
-                        package_name = package.name,
-                        urls = package.url,
-                        sha256 = package.sha256,
-                    ),
-                )
-
-            repo_name = "%s%s" % ("@" if lock_content else "", deb_import_key)
-
             rctx.file(
                 "%s/%s/BUILD.bazel" % (package.name, package.arch),
-                package_template.format(
-                    target_name = package.arch,
-                    src = '"@%s//:data"' % repo_name,
-                    deps = ",\n        ".join([
-                        '"//%s/%s"' % (dep.name, package.arch)
-                        for dep in package.dependencies
-                    ]),
-                    urls = [package.url],
-                    name = package.name,
-                    arch = package.arch,
-                    sha256 = package.sha256,
-                    repo_name = "%s" % repo_name,
+                package_arch_build(
+                    package,
+                    repo_prefix,
+                    repo_name,
+                    rctx.read(rctx.attr.package_arch_build_template),
                 ),
             )
 
-    rctx.file("packages.bzl", "\n".join(package_defs))
+    if rctx.attr.lock_content:
+        packages_bzl = ""
+    else:
+        packages_bzl = deb_packages(repo_name, lockf.packages)
+
+    rctx.file("packages.bzl", packages_bzl)
     rctx.file("BUILD.bazel", _BUILD_TMPL.format(rctx.attr.name.split("~")[-1]))
 
 deb_package_index = repository_rule(
@@ -85,5 +48,6 @@ deb_package_index = repository_rule(
         "lock": attr.label(),
         "lock_content": attr.string(doc = "INTERNAL: DO NOT USE"),
         "package_template": attr.label(default = "//apt/private:package.BUILD.tmpl"),
+        "package_arch_build_template": attr.label(default = "//apt/private:package_arch.BUILD.tmpl"),
     },
 )

apt/private/package.BUILD.tmpl → apt/private/package_arch.BUILD.tmpl

@@ -1,3 +1,5 @@
+"""Generated by rules_distroless. DO NOT EDIT."""
+
 alias(
     name = "data",
     actual = "@{repo_name}//:data",
@@ -12,8 +14,6 @@ alias(
 
 filegroup(
     name = "{target_name}",
+    srcs = {deps}
     visibility = ["//visibility:public"],
-    srcs = [
-        {deps}
-    ] + [":data"]
-)
+)