api/build: switch to only package level targets in API.

As part of envoyproxy#8082, we want to be able to (1) automatically generate BUILD
files and (2) treat packages as atomic from a "upgrade / do not upgrade"
decision perspective. This is simplified by having our BUILD targets at
package granularity, since this is what the protoxform plugin operates
on.

This PR broadens the package-level treatment that was already introduced
for Go in envoyproxy#8003 to Python and C++. This simplifies BUILD files
significantly and opens the way to automated generation.

There is some technical debt introduced, since all visibility controls
have been removed. This is slated for reintroduction in
envoyproxy#8491.

As a bonus (useful for BUILD file generation), also removed the
inconsistency in BUILD package target naming for packages in envoy.api.*
and envoy.type.*. E.g. //envoy/api/v2:v2 is now //envoy/api/v2:pkg.

Risk level: Low (but this will break internal builds and require BUILD
fixups to consuming projects).
Testing: bazel test //test/... @envoy_api//...

Signed-off-by: Harvey Tuch <htuch@google.com>

api/bazel/api_build_system.bzl

@@ -4,10 +4,9 @@ load("@io_bazel_rules_go//proto:def.bzl", "go_grpc_library", "go_proto_library")
 load("@io_bazel_rules_go//go:def.bzl", "go_test")
 load("@com_github_grpc_grpc//bazel:cc_grpc_library.bzl", "cc_grpc_library")
 
-_PY_SUFFIX = "_py"
-_CC_SUFFIX = "_cc"
+_PY_PROTO_SUFFIX = "_py_proto"
+_CC_PROTO_SUFFIX = "_cc_proto"
 _CC_GRPC_SUFFIX = "_cc_grpc"
-_CC_EXPORT_SUFFIX = "_export_cc"
 _GO_PROTO_SUFFIX = "_go_proto"
 _GO_IMPORTPATH_PREFIX = "github.com/envoyproxy/go-control-plane/"
 
@@ -20,30 +19,59 @@ _COMMON_PROTO_DEPS = [
     "@com_google_protobuf//:timestamp_proto",
     "@com_google_protobuf//:wrappers_proto",
     "@com_google_googleapis//google/api:http_proto",
+    "@com_google_googleapis//google/api:httpbody_proto",
     "@com_google_googleapis//google/api:annotations_proto",
     "@com_google_googleapis//google/rpc:status_proto",
     "@com_envoyproxy_protoc_gen_validate//validate:validate_proto",
 ]
 
+_GO_BAZEL_RULE_MAPPING = {
+    "@opencensus_proto//opencensus/proto/trace/v1:trace_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_proto_go",
+    "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_and_config_proto_go",
+    "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto": "@com_google_googleapis//google/api/expr/v1alpha1:cel_go_proto",
+}
+
+_CC_BAZEL_RULE_MAPPING = {
+    "@opencensus_proto//opencensus/proto/trace/v1:trace_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_proto_cc",
+    "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto_cc",
+    "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto": "@com_google_googleapis//google/api/expr/v1alpha1:syntax_cc_proto",
+}
+
+_PY_BAZEL_RULE_MAPPING = {
+    "@opencensus_proto//opencensus/proto/trace/v1:trace_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_proto_py",
+    "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto_py",
+    "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto": "@com_google_googleapis//google/api/expr/v1alpha1:syntax_py_proto",
+}
+
 def _Suffix(d, suffix):
     return d + suffix
 
-def _LibrarySuffix(library_name, suffix):
-    # Transform //a/b/c to //a/b/c:c in preparation for suffix operation below.
-    if library_name.startswith("//") and ":" not in library_name:
-        library_name += ":" + Label(library_name).name
-    return _Suffix(library_name, suffix)
+def _proto_mapping(dep, proto_dep_map, proto_suffix):
+    mapped = proto_dep_map.get(dep)
+    if mapped == None:
+        prefix = "@" + Label(dep).workspace_name if not dep.startswith("//") else ""
+        return _Suffix(prefix + "//" + Label(dep).package + ":" + Label(dep).name, proto_suffix)
+    return mapped
+
+def _go_proto_mapping(dep):
+    return _proto_mapping(dep, _GO_BAZEL_RULE_MAPPING, _GO_PROTO_SUFFIX)
+
+def _cc_proto_mapping(dep):
+    return _proto_mapping(dep, _CC_BAZEL_RULE_MAPPING, _CC_PROTO_SUFFIX)
+
+def _py_proto_mapping(dep):
+    return _proto_mapping(dep, _PY_BAZEL_RULE_MAPPING, _PY_PROTO_SUFFIX)
 
 # TODO(htuch): Convert this to native py_proto_library once
 # https://github.com/bazelbuild/bazel/issues/3935 and/or
 # https://github.com/bazelbuild/bazel/issues/2626 are resolved.
-def api_py_proto_library(name, srcs = [], deps = [], external_py_proto_deps = []):
+def _api_py_proto_library(name, srcs = [], deps = []):
     _py_proto_library(
-        name = _Suffix(name, _PY_SUFFIX),
+        name = _Suffix(name, _PY_PROTO_SUFFIX),
         srcs = srcs,
         default_runtime = "@com_google_protobuf//:protobuf_python",
         protoc = "@com_google_protobuf//:protoc",
-        deps = [_LibrarySuffix(d, _PY_SUFFIX) for d in deps] + external_py_proto_deps + [
+        deps = [_py_proto_mapping(dep) for dep in deps] + [
             "@com_envoyproxy_protoc_gen_validate//validate:validate_py",
             "@com_google_googleapis//google/rpc:status_py_proto",
             "@com_google_googleapis//google/api:annotations_py_proto",
@@ -83,113 +111,65 @@ def _api_cc_grpc_library(name, proto, deps = []):
         visibility = ["//visibility:public"],
     )
 
-def _ToCanonicalLabel(label):
-    # //my/app and //my/app:app are the same label. In places we mutate the incoming label adding different suffixes
-    # in order to generate multiple targets in a single rule. //my/app:app_grpc_cc.
-    # Skylark formatters and linters prefer the shorthand label whilst we need the latter.
-    rel = Label("//" + native.package_name()).relative(label)
-    return "//" + rel.package + ":" + rel.name
-
-# This is api_proto_library plus some logic internal to //envoy/api.
-def api_proto_library_internal(visibility = ["//visibility:private"], **kwargs):
-    # //envoy/docs/build.sh needs visibility in order to generate documents.
-    if visibility == ["//visibility:private"]:
-        visibility = ["//docs"]
-    elif visibility != ["//visibility:public"]:
-        visibility = visibility + ["//docs"]
-
-    api_proto_library(visibility = visibility, **kwargs)
-
-def api_proto_library(
+def api_cc_py_proto_library(
         name,
         visibility = ["//visibility:private"],
         srcs = [],
         deps = [],
-        tags = [],
-        external_proto_deps = [],
-        external_cc_proto_deps = [],
-        external_py_proto_deps = [],
-        has_services = 0,
-        linkstatic = None,
-        require_py = 1):
+        linkstatic = 0,
+        has_services = 0):
     relative_name = ":" + name
     native.proto_library(
         name = name,
         srcs = srcs,
-        deps = deps + external_proto_deps + _COMMON_PROTO_DEPS,
-        tags = tags,
+        deps = deps + _COMMON_PROTO_DEPS,
         visibility = visibility,
     )
-    cc_proto_library_name = _Suffix(name, _CC_SUFFIX)
+    cc_proto_library_name = _Suffix(name, _CC_PROTO_SUFFIX)
     pgv_cc_proto_library(
         name = cc_proto_library_name,
         linkstatic = linkstatic,
-        cc_deps = [_LibrarySuffix(d, _CC_SUFFIX) for d in deps] + external_cc_proto_deps + [
+        cc_deps = [_cc_proto_mapping(dep) for dep in deps] + [
             "@com_google_googleapis//google/api:http_cc_proto",
+            "@com_google_googleapis//google/api:httpbody_cc_proto",
             "@com_google_googleapis//google/api:annotations_cc_proto",
             "@com_google_googleapis//google/rpc:status_cc_proto",
         ],
         deps = [relative_name],
         visibility = ["//visibility:public"],
     )
-    py_export_suffixes = []
-    if require_py:
-        api_py_proto_library(name, srcs, deps, external_py_proto_deps)
-        py_export_suffixes = ["_py", "_py_genproto"]
+    _api_py_proto_library(name, srcs, deps)
 
     # Optionally define gRPC services
     if has_services:
         # TODO: when Python services are required, add to the below stub generations.
         cc_grpc_name = _Suffix(name, _CC_GRPC_SUFFIX)
-        cc_proto_deps = [cc_proto_library_name] + [_Suffix(_ToCanonicalLabel(x), _CC_SUFFIX) for x in deps]
+        cc_proto_deps = [cc_proto_library_name] + [_cc_proto_mapping(dep) for dep in deps]
         _api_cc_grpc_library(name = cc_grpc_name, proto = relative_name, deps = cc_proto_deps)
 
-    # Allow unlimited visibility for consumers
-    export_suffixes = ["", "_cc", "_cc_validate"] + py_export_suffixes
-    for s in export_suffixes:
-        native.alias(
-            name = name + "_export" + s,
-            actual = name + s,
-            visibility = ["//visibility:public"],
-        )
-
-def api_cc_test(name, srcs, proto_deps):
+def api_cc_test(name, **kwargs):
     native.cc_test(
         name = name,
-        srcs = srcs,
-        deps = [_LibrarySuffix(d, _CC_EXPORT_SUFFIX) for d in proto_deps],
+        **kwargs
     )
 
-def api_go_test(name, size, importpath, srcs = [], deps = []):
+def api_go_test(name, **kwargs):
     go_test(
         name = name,
-        size = size,
-        srcs = srcs,
-        importpath = importpath,
-        deps = deps,
+        **kwargs
     )
 
-_GO_BAZEL_RULE_MAPPING = {
-    "@opencensus_proto//opencensus/proto/trace/v1:trace_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_proto_go",
-    "@opencensus_proto//opencensus/proto/trace/v1:trace_config_proto": "@opencensus_proto//opencensus/proto/trace/v1:trace_and_config_proto_go",
-    "@com_google_googleapis//google/api/expr/v1alpha1:syntax_proto": "@com_google_googleapis//google/api/expr/v1alpha1:cel_go_proto",
-}
-
-def go_proto_mapping(dep):
-    mapped = _GO_BAZEL_RULE_MAPPING.get(dep)
-    if mapped == None:
-        return _Suffix("@" + Label(dep).workspace_name + "//" + Label(dep).package + ":" + Label(dep).name, _GO_PROTO_SUFFIX)
-    return mapped
-
-def api_proto_package(name = "pkg", srcs = [], deps = [], has_services = False, visibility = ["//visibility:public"]):
+def api_proto_package(srcs = [], deps = [], has_services = False, visibility = ["//visibility:public"]):
     if srcs == []:
         srcs = native.glob(["*.proto"])
 
-    native.proto_library(
+    name = "pkg"
+    api_cc_py_proto_library(
         name = name,
-        srcs = srcs,
-        deps = deps + _COMMON_PROTO_DEPS,
         visibility = visibility,
+        srcs = srcs,
+        deps = deps,
+        has_services = has_services,
     )
 
     compilers = ["@io_bazel_rules_go//proto:go_proto", "//bazel:pgv_plugin_go"]
@@ -202,7 +182,7 @@ def api_proto_package(name = "pkg", srcs = [], deps = [], has_services = False,
         importpath = _Suffix(_GO_IMPORTPATH_PREFIX, native.package_name()),
         proto = name,
         visibility = ["//visibility:public"],
-        deps = [go_proto_mapping(dep) for dep in deps] + [
+        deps = [_go_proto_mapping(dep) for dep in deps] + [
             "@com_github_golang_protobuf//ptypes:go_default_library",
             "@com_github_golang_protobuf//ptypes/any:go_default_library",
             "@com_github_golang_protobuf//ptypes/duration:go_default_library",

api/bazel/repositories.bzl

@@ -41,10 +41,10 @@ def api_dependencies():
     )
 
 PROMETHEUSMETRICS_BUILD_CONTENT = """
-load("@envoy_api//bazel:api_build_system.bzl", "api_proto_library")
+load("@envoy_api//bazel:api_build_system.bzl", "api_cc_py_proto_library")
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 
-api_proto_library(
+api_cc_py_proto_library(
     name = "client_model",
     srcs = [
         "metrics.proto",
@@ -61,10 +61,10 @@ go_proto_library(
 """
 
 OPENCENSUSTRACE_BUILD_CONTENT = """
-load("@envoy_api//bazel:api_build_system.bzl", "api_proto_library")
+load("@envoy_api//bazel:api_build_system.bzl", "api_cc_py_proto_library")
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 
-api_proto_library(
+api_cc_py_proto_library(
     name = "trace_model",
     srcs = [
         "trace.proto",
@@ -102,10 +102,10 @@ filegroup(
 
 ZIPKINAPI_BUILD_CONTENT = """
 
-load("@envoy_api//bazel:api_build_system.bzl", "api_proto_library")
+load("@envoy_api//bazel:api_build_system.bzl", "api_cc_py_proto_library")
 load("@io_bazel_rules_go//proto:def.bzl", "go_proto_library")
 
-api_proto_library(
+api_cc_py_proto_library(
     name = "zipkin",
     srcs = [
         "zipkin-jsonv2.proto",