Method start

3rdparty/libprocess/src/memory_profiler.cpp:659–725

TODO(bevers): Add a query parameter to select json or html format. TODO(bevers): Add a query parameter to configure the sampling interval.

// TODO(bevers): Add a query parameter to select json or html format.
// TODO(bevers): Add a query parameter to configure the sampling interval.
Future<http::Response> MemoryProfiler::start(
  const http::Request& request,
  const Option<http::authentication::Principal>&)
{
  if (!detectJemalloc()) {
    return http::BadRequest(string(JEMALLOC_NOT_DETECTED_MESSAGE) + ".\n");
  }

  Duration duration = DEFAULT_COLLECTION_TIME;

  // TODO(bevers): Introduce `http::Request::extractQueryParameter<T>(string)`
  // instead of doing it ad-hoc here.
  Option<string> durationParameter = request.url.query.get("duration");
  if (durationParameter.isSome()) {
    Try<Duration> parsed = Duration::parse(durationParameter.get());
    if (parsed.isError()) {
      return http::BadRequest(
          "Could not parse parameter 'duration': " + parsed.error() + ".\n");
    }
    duration = parsed.get();
  }

  if (duration < MINIMUM_COLLECTION_TIME ||
      duration > MAXIMUM_COLLECTION_TIME) {
    return http::BadRequest(
        "Duration '" + stringify(duration) + "' must be between "
        + stringify(MINIMUM_COLLECTION_TIME) + " and "
        + stringify(MAXIMUM_COLLECTION_TIME) + ".\n");
  }

  Try<bool> wasActive = jemalloc::startProfiling();
  if (wasActive.isError()) {
    return http::BadRequest(
        string(JEMALLOC_PROFILING_NOT_ENABLED_MESSAGE) + ".\n");
  }

  if (!wasActive.get()) {
    time_t id = std::chrono::system_clock::to_time_t(
        std::chrono::system_clock::now());
    currentRun = ProfilingRun(this, id, duration);
  }

  JSON::Object response;

  // This can happen when jemalloc was configured e.g. via the `MALLOC_CONF`
  // environment variable. We don't touch it in this case.
  if (!currentRun.isSome()) {
    return http::Conflict("Heap profiling was started externally.\n");
  }

  string message = wasActive.get() ?
    "Heap profiling is already active." :
    "Successfully started new heap profiling run.";

  message +=
    " After the remaining time elapses, download the generated profile at '/" +
    this->self().id + "/download/raw?id=" + stringify(currentRun->id) + "'." +
    " Visit '/" + this->self().id + "/stop' to stop collection earlier.";