report process name and uptime for each connected client

Summary:
It's helpful to know the set of connected clients, when they
connected, and what their status is. Include pid and command line and
uptime in `watchman debug-status`.

Reviewed By: kmancini

Differential Revision: D37436553

fbshipit-source-id: dc9488dab4a0b2e1fd6860a65d3a73bdd5a1e712

CMakeLists.txt

@@ -342,10 +342,10 @@ find_package(
 find_package(LibEvent REQUIRED)
 get_filename_component(LIBEVENT_LIBDIR "${LIBEVENT_LIB}" DIRECTORY)
 link_directories(${LIBEVENT_LIBDIR})
+find_package(edencommon CONFIG REQUIRED)
 find_package(fmt CONFIG REQUIRED)
 find_package(folly CONFIG REQUIRED)
 
-
 if (ENABLE_EDEN_SUPPORT)
   find_package(fizz CONFIG REQUIRED)
   find_package(wangle CONFIG REQUIRED)
@@ -704,6 +704,7 @@ target_link_libraries(
   jansson
   wildmatch
   third_party_deps
+  edencommon::utils
 )
 
 if (WIN32)

build/fbcode_builder/manifests/watchman

@@ -13,6 +13,7 @@ builder = cmake
 [dependencies]
 boost
 cpptoml
+edencommon
 fb303
 fbthrift
 folly

watchman/Client.cpp

@@ -23,6 +23,17 @@ namespace watchman {
 
 namespace {
 
+using namespace facebook::eden;
+
+ProcessNameCache& getProcessNameCache() {
+  static auto* pnc = new ProcessNameCache;
+  return *pnc;
+}
+
+ProcessNameHandle lookupProcessName(pid_t pid) {
+  return getProcessNameCache().lookup(pid);
+}
+
 constexpr size_t kResponseLogLimit = 0;
 
 folly::Synchronized<std::unordered_set<UserClient*>> clients;
@@ -209,7 +220,10 @@ void UserClient::create(std::unique_ptr<watchman_stream> stm) {
 }
 
 UserClient::UserClient(PrivateBadge, std::unique_ptr<watchman_stream> stm)
-    : Client(std::move(stm)) {
+    : Client{std::move(stm)},
+      since_{std::chrono::system_clock::now()},
+      peerPid_{this->stm->getPeerProcessID()},
+      peerName_{lookupProcessName(peerPid_)} {
   clients.wlock()->insert(this);
 }
 
@@ -246,6 +260,13 @@ std::vector<ClientDebugStatus> UserClient::getStatusForAllClients() {
 ClientDebugStatus UserClient::getDebugStatus() const {
   ClientDebugStatus rv;
   rv.state = status_.getName();
+  if (peerPid_) {
+    rv.peer.emplace();
+    rv.peer->pid = peerPid_;
+    // May briefly, once, block on the ProcessNameCache thread.
+    rv.peer->name = peerName_.get();
+  }
+  rv.since = std::chrono::system_clock::to_time_t(since_);
   return rv;
 }
 

watchman/Client.h

@@ -6,9 +6,14 @@
  */
 
 #pragma once
+
+#include <eden/common/utils/ProcessNameCache.h>
 #include <fmt/format.h>
+
+#include <chrono>
 #include <deque>
 #include <unordered_map>
+
 #include "watchman/Clock.h"
 #include "watchman/CommandRegistry.h"
 #include "watchman/Logging.h"
@@ -154,12 +159,27 @@ class ClientStatus {
   std::atomic<State> state_{THREAD_STARTING};
 };
 
+struct PeerInfo : serde::Object {
+  int32_t pid;
+  std::string name;
+
+  template <typename X>
+  void map(X& x) {
+    x("pid", pid);
+    x("name", name);
+  }
+};
+
 struct ClientDebugStatus : serde::Object {
   std::string state;
+  std::optional<PeerInfo> peer;
+  std::optional<int64_t> since;
 
   template <typename X>
   void map(X& x) {
     x("state", state);
+    x("peer", peer);
+    x("since", since);
   }
 };
 
@@ -214,6 +234,10 @@ class UserClient final : public Client {
 
   void clientThread() noexcept;
 
+  const std::chrono::system_clock::time_point since_;
+  const pid_t peerPid_;
+  const facebook::eden::ProcessNameHandle peerName_;
+
   ClientStatus status_;
 };
 

watchman/cmds/debug.cpp

@@ -5,7 +5,10 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+#include <fmt/chrono.h>
+#include <folly/String.h>
 #include <folly/chrono/Conv.h>
+#include <folly/system/Shell.h>
 #include <unordered_map>
 #include "watchman/Client.h"
 #include "watchman/InMemoryView.h"
@@ -227,6 +230,28 @@ W_CMD_REG(
     CMD_DAEMON,
     w_cmd_realpath_root);
 
+namespace {
+
+std::string shellQuoteCommand(std::string_view command) {
+  std::vector<std::string> argv;
+  folly::split('\0', command, argv);
+
+  // Every argument in a command line is null-terminated. Remove the last, empty
+  // argument.
+  if (argv.size() && argv.back().empty()) {
+    argv.pop_back();
+  }
+
+  for (auto& arg : argv) {
+    // TODO: shellQuote is not particularly good. It always brackets with ' and
+    // does not handle non-printable characters. We should write our own.
+    arg = folly::shellQuote(arg);
+  }
+  return folly::join(' ', argv);
+}
+
+} // namespace
+
 struct DebugStatusCommand : PrettyCommand<DebugStatusCommand> {
   static constexpr std::string_view name = "debug-status";
 
@@ -273,7 +298,19 @@ struct DebugStatusCommand : PrettyCommand<DebugStatusCommand> {
 
     fmt::print("CLIENTS\n-------\n");
     for (auto& client : response.clients) {
+      if (client.peer) {
+        fmt::print(
+            "{}: {}\n", client.peer->pid, shellQuoteCommand(client.peer->name));
+      } else {
+        fmt::print("unknown peer\n");
+      }
+      if (client.since) {
+        fmt::print(
+            "  - since: {}\n",
+            std::chrono::system_clock::from_time_t(client.since.value()));
+      }
       fmt::print("  - state: {}\n", client.state);
+      fmt::print("\n");
     }
   }
 };