Add test kernel log generator.

test/kernel_log_generator/generator.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+
+# Copyright 2017 The Kubernetes Authors.
+#
+# 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.
+
+# This script generate kernel log in given rate.
+# Note that this only works for journald.
+# Note that this script can't be used to test multi-line patterns, because
+# the test kernel log lines may be splitted by real kernel log.
+
+# PROBLEM is the path to the problem log.
+PROBLEM=${PROBLEM:-""}
+# LINES_PER_SECOND is the log generating rate.
+LINES_PER_SECOND=${LINES_PER_SECOND:-1}
+# LOG_PATH is the path to generate kernel logs.
+LOG_PATH=${LOG_PATH:-"/dev/kmsg"}
+# RUN_ONCE specifies whether to keep generating problem logs or only
+# generate once.
+RUN_ONCE=${RUN_ONCE:-"false"}
+
+if [[ -z ${PROBLEM} ]]; then
+  echo "$(basename $0): PROBLEM is empty"
+  exit 1
+fi
+
+# now returns the current unix time in micro seconds
+now() {
+  echo $(($(date +'%s%N') / 1000))
+}
+
+prefix="kernel: "
+logs=$(<${PROBLEM})
+lines=$(printf "%s\n" "${logs}" | wc -l)
+current_lines=0
+start=$(now)
+while true; do
+  while read log; do
+    echo "${prefix}${log}" >> ${LOG_PATH}
+    ((current_lines++))
+    if [[ ${current_lines} == ${LINES_PER_SECOND} ]]; then
+      current_lines=0
+      current=$(now)
+      duration=$((1000000 - current + start))
+      if [[ ${duration} -gt 0 ]]; then
+        echo "generated ${LINES_PER_SECOND} lines of log, sleep for ${duration}"
+        usleep ${duration}
+      fi
+      start=$(now)
+    fi
+  done <<< "$logs"
+  if [[ "${RUN_ONCE}" == "true" ]]; then
+    echo "stop the generator"
+    exit 0
+  fi
+done