Add ci scripts (#1)

* Add ci scripts

* Move config files to ci/kokoro/docker

* Remove dump-logs etc

* Simplified grpc installation

* Add Ubuntu 16.04 kokoro config

* Address code review

ci/retry-command.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eu
+
+# Make three attempts to install the dependencies. It is rare, but from time to
+# time the downloading the packages, building the Docker images, or an installer
+# Bazel, or the Google Cloud SDK fails. To make the CI build more robust, try
+# again when that happens.
+
+if (( $# < 1 )); then
+  echo "Usage: $(basename "$0") program [arguments]"
+  exit 1
+fi
+readonly PROGRAM=${1}
+shift
+
+# Initially, wait at least 2 minutes (the times are in seconds), because it
+# makes no sense to try faster. This used to be 180 seconds, but that ends with
+# sleeps close to 10 minutes, and Travis aborts builds that do not output in
+# 10m.
+min_wait=120
+# Do not exit on failures for this loop.
+set +e
+for i in 1 2 3; do
+  if "${PROGRAM}" "$@"; then
+    exit 0
+  fi
+  # Sleep for a few minutes before trying again.
+  period=$(( (RANDOM % 60) + min_wait ))
+  echo "${PROGRAM} failed (attempt ${i}); trying again in ${period} seconds."
+  sleep ${period}s
+  min_wait=$(( min_wait * 2 ))
+done
+
+exit 1