Use select to decide the test is hermetic or not

BUILD

@@ -38,6 +38,11 @@ config_setting(
     values = {"define": "grpc_no_ares=true"},
 )
 
+config_setting(
+    name = "remote_execution",
+    values = {"define": "GRPC_HERMETIC_TESTS=1"},
+)
+
 # This should be updated along with build.yaml
 g_stands_for = "generous"
 

bazel/grpc_build_system.bzl

@@ -26,17 +26,17 @@
 def grpc_cc_library(name, srcs = [], public_hdrs = [], hdrs = [],
                     external_deps = [], deps = [], standalone = False,
                     language = "C++", testonly = False, visibility = None,
-                    alwayslink = 0, defines = []):
+                    alwayslink = 0):
   copts = []
   if language.upper() == "C":
     copts = ["-std=c99"]
   native.cc_library(
     name = name,
     srcs = srcs,
-    defines = select({
-        "//:grpc_no_ares": ["GRPC_ARES=0"],
-	"//conditions:default": defines,
-    }),
+    defines = select({"//:grpc_no_ares": ["GRPC_ARES=0"],
+                      "//conditions:default": [],}) +
+              select({"//:remote_execution":  ["GRPC_HERMETIC_TESTS=1"],
+                      "//conditions:default": [],}),
     hdrs = hdrs + public_hdrs,
     deps = deps + ["//external:" + dep for dep in external_deps],
     copts = copts,

test/core/util/BUILD

@@ -74,9 +74,6 @@ grpc_cc_library(
         "tracer_util.h",
         "trickle_endpoint.h",
     ],
-    defines = [
-        "GRPC_HERMETIC_TESTS=1",
-    ],
     language = "C++",
     deps = [
         ":gpr_test_util",

test/core/util/port_hermetic.cc

@@ -16,6 +16,10 @@
  *
  */
 
+/* When running tests hermeticly, i.e. running on remote machines, 
+ * the framework takes a round-robin pick of a port within certain range. 
+ * There is no need to recycle ports.
+ */
 #include "src/core/lib/iomgr/port.h"
 #include "test/core/util/test_config.h"
 #if defined(GRPC_HERMETIC_TESTS)

tools/internal_ci/linux/grpc_bazel_on_foundry.sh

@@ -48,4 +48,5 @@ source tools/internal_ci/helper_scripts/prepare_build_linux_rc
   --experimental_strict_action_env=true \
   --experimental_remote_platform_override='properties:{name:"container-image" value:"docker://gcr.io/asci-toolchain/nosla-debian8-clang-fl@sha256:aa20628a902f06a11a015caa94b0432eb60690de2d2525bd046b9eea046f5d8a" }' \
   --crosstool_top=@bazel_toolchains//configs/debian8_clang/0.2.0/bazel_0.7.0:toolchain \
+  --define GRPC_HERMETIC_TESTS=1 \
   -- //test/...