Re-write run_local_tests.sh to run the tests in parallel.

When I profiled this change locally, the runtime of the script was reduced from about 30 minutes down to 12 minutes when the blaze commands were run in parallel. This makes sense because a lot of the time is spent just waiting for Kokoro to perform the build.

PiperOrigin-RevId: 330748434

Author: Googler

firestore/run_local_tests.sh

@@ -3,9 +3,99 @@
 # TAP or Guitar at the moment (see b/135205911). Execute this script before
 # submitting.
 
+set -euo pipefail
+
+# Executes blaze to run a Kokoro test.
+#
+# The first argument is the name of an associative array variable. A key/value
+# pair will be inserted into this associative array with information about the
+# launched blaze process. The key will be the PID of the blaze process and the
+# value will be the full blaze command that was executed.
+#
+# The second argument is the "name" of the test, and is used in the subdirectory
+# name of the directory specified to blaze's --output_base argument.
+#
+# The remaining arguments, if any, will be specified to the blaze command after
+# the "test" argument.
+function run_blaze {
+  if [[ $# -lt 2 ]] ; then
+    echo "INTERNAL ERROR: run_blaze invalid arguments: $*" >&2
+    exit 1
+  fi
+
+  local -n readonly blaze_process_map="$1"
+  local readonly blaze_build_name="$2"
+  shift 2
+
+  local readonly blaze_args=(
+    "blaze"
+    "--blazerc=/dev/null"
+    "--output_base=/tmp/run_local_tests_blaze_output_bases/${blaze_build_name}"
+    "test"
+    "$@"
+    "//firebase/firestore/client/cpp:kokoro_build_test"
+  )
+
+  echo "${blaze_args[*]}"
+  "${blaze_args[@]}" &
+  blaze_process_map["$!"]="${blaze_args[*]}"
+}
+
+# Waits for blaze commands started by `run_blaze` to complete.
+#
+# If all blaze commands complete successfully then a "success" message is
+# printed; otherwise, if one or more of the blaze commands fail, then an error
+# message is printed.
+#
+# The first (and only) argument is the name of an associative array variable.
+# This variable should be the same that was was specified to `run_blaze` and
+# specifies the blaze commands for which to wait.
+#
+# The return value is 0 if all blaze processes completed successfully or 1 if
+# one or more of the blaze processes failed.
+function wait_for_blazes_to_complete {
+  if [[ $# -ne 1 ]] ; then
+    echo "INTERNAL ERROR: wait_for_blazes_to_complete invalid arguments: $*" >&2
+    exit 1
+  fi
+
+  local -n blaze_process_map="$1"
+
+  local blaze_pid
+  local -a blaze_failed_pids=()
+
+  for blaze_pid in "${!blaze_process_map[@]}" ; do
+    if ! wait "${blaze_pid}" ; then
+      blaze_failed_pids+=("${blaze_pid}")
+    fi
+  done
+
+  local readonly num_failed_blazes="${#blaze_failed_pids[@]}"
+  if [[ ${num_failed_blazes} -eq 0 ]] ; then
+    echo "All blaze commands completed successfully."
+  else
+    echo "ERROR: The following ${num_failed_blazes} blaze invocation(s) failed:"
+    for blaze_pid in "${blaze_failed_pids[@]}" ; do
+      echo "${blaze_process_map[${blaze_pid}]}"
+    done
+    echo "Go to http://sponge2 to see the results."
+    return 1
+  fi
+}
+
+# The main program begins here.
+if [[ $# -gt 0 ]] ; then
+  echo "ERROR: $0 does not accept any arguments, but got: $*" >&2
+  exit 2
+fi
+
+declare -A BLAZE_PROCESS_MAP
+
 # LINT.IfChange
-blaze test --config=android_arm //firebase/firestore/client/cpp:kokoro_build_test && \
-blaze test --config=darwin_x86_64 //firebase/firestore/client/cpp:kokoro_build_test && \
-blaze test --define=force_regular_grpc=1 //firebase/firestore/client/cpp:kokoro_build_test && \
-blaze test --config=msvc //firebase/firestore/client/cpp:kokoro_build_test
+run_blaze "BLAZE_PROCESS_MAP" "android_arm" "--config=android_arm"
+run_blaze "BLAZE_PROCESS_MAP" "darwin_x86_64" "--config=darwin_x86_64"
+run_blaze "BLAZE_PROCESS_MAP" "linux" "--define=force_regular_grpc=1"
+run_blaze "BLAZE_PROCESS_MAP" "msvc" "--config=msvc"
 # LINT.ThenChange(//depot_firebase_cpp/firestore/client/cpp/METADATA)
+
+wait_for_blazes_to_complete "BLAZE_PROCESS_MAP"