in hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/server/http/ProfileServlet.java [218:367]
protected void doGet(final HttpServletRequest req,
final HttpServletResponse resp) throws IOException {
// make sure async profiler home is set
if (StringUtils.isBlank(asyncProfilerHome)) {
resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
setResponseHeader(resp);
resp.getWriter().write("ASYNC_PROFILER_HOME env is not set.");
return;
}
//download the finished file
if (req.getParameter("file") != null) {
doGetDownload(req.getParameter("file"), req, resp);
return;
}
// if pid is explicitly specified, use it else default to current process
Integer processId = getInteger(req, "pid", pid);
// if pid is not specified in query param and if current process pid
// cannot be determined
if (processId == null) {
resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
setResponseHeader(resp);
resp.getWriter().write(
"'pid' query parameter unspecified or unable to determine PID of "
+ "current process.");
return;
}
final int duration =
getInteger(req, "duration", DEFAULT_DURATION_SECONDS);
final Output output = getOutput(req);
final Event event = getEvent(req);
final Long interval = getLong(req, "interval");
final Integer jstackDepth = getInteger(req, "jstackdepth", null);
final Long bufsize = getLong(req, "bufsize");
final boolean thread = req.getParameterMap().containsKey("thread");
final boolean simple = req.getParameterMap().containsKey("simple");
final Integer width = getInteger(req, "width", null);
final Integer height = getInteger(req, "height", null);
final Double minwidth = getMinWidth(req);
final boolean reverse = req.getParameterMap().containsKey("reverse");
if (process == null || !process.isAlive()) {
try {
int lockTimeoutSecs = 3;
if (profilerLock.tryLock(lockTimeoutSecs, TimeUnit.SECONDS)) {
try {
//Should be in sync with FILE_NAME_PATTERN
File outputFile =
OUTPUT_DIR.resolve(
ProfileServlet.generateFileName(processId, output, event))
.toFile();
List<String> cmd = new ArrayList<>();
cmd.add(asyncProfilerHome + PROFILER_SCRIPT);
cmd.add("-e");
cmd.add(event.getInternalName());
cmd.add("-d");
cmd.add(String.valueOf(duration));
cmd.add("-o");
cmd.add(output.name().toLowerCase());
cmd.add("-f");
cmd.add(outputFile.getAbsolutePath());
if (interval != null) {
cmd.add("-i");
cmd.add(interval.toString());
}
if (jstackDepth != null) {
cmd.add("-j");
cmd.add(jstackDepth.toString());
}
if (bufsize != null) {
cmd.add("-b");
cmd.add(bufsize.toString());
}
if (thread) {
cmd.add("-t");
}
if (simple) {
cmd.add("-s");
}
if (width != null) {
cmd.add("--width");
cmd.add(width.toString());
}
if (height != null) {
cmd.add("--height");
cmd.add(height.toString());
}
if (minwidth != null) {
cmd.add("--minwidth");
cmd.add(minwidth.toString());
}
if (reverse) {
cmd.add("--reverse");
}
cmd.add(processId.toString());
process = runCmdAsync(cmd);
// set response and set refresh header to output location
setResponseHeader(resp);
resp.setStatus(HttpServletResponse.SC_ACCEPTED);
String relativeUrl = "/prof?file=" + outputFile.getName();
resp.getWriter().write(
"Started [" + event.getInternalName()
+ "] profiling. This page will automatically redirect to "
+
relativeUrl + " after " + duration
+ " seconds.\n\ncommand:\n" + Joiner.on(" ").join(cmd));
resp.getWriter().write(
"\n\n\nPlease make sure that you enabled the profiling on "
+ "kernel level:\n"
+ "echo 1 > /proc/sys/kernel/perf_event_paranoid\n"
+ "echo 0 > /proc/sys/kernel/kptr_restrict\n\n"
+ "See https://github"
+ ".com/jvm-profiling-tools/async-profiler#basic-usage"
+ " for more details.");
// to avoid auto-refresh by ProfileOutputServlet, refreshDelay
// can be specified via url param
int refreshDelay = getInteger(req, "refreshDelay", 0);
// instead of sending redirect, set auto-refresh so that browsers
// will refresh with redirected url
resp.setHeader("Refresh",
(duration + refreshDelay) + ";" + relativeUrl);
resp.getWriter().flush();
} finally {
profilerLock.unlock();
}
} else {
setResponseHeader(resp);
resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
resp.getWriter().write(
"Unable to acquire lock. Another instance of profiler might be "
+ "running.");
LOG.warn("Unable to acquire lock in {} seconds. Another instance of "
+ "profiler might be running.", lockTimeoutSecs);
}
} catch (InterruptedException e) {
LOG.warn("Interrupted while acquiring profile lock.", e);
resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
Thread.currentThread().interrupt();
}
} else {
setResponseHeader(resp);
resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
resp.getWriter()
.write("Another instance of profiler is already running.");
}
}