1 files changed, 239 insertions, 0 deletions
diff --git a/src/core/lib/channel/channel_trace.cc b/src/core/lib/channel/channel_trace.cc
new file mode 100644
index 0000000000..654300cd32
--- /dev/null
+++ b/src/core/lib/channel/channel_trace.cc
@@ -0,0 +1,239 @@
+/*
+ *
+ * Copyright 2017 gRPC 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.
+ *
+ */
+
+#include <grpc/impl/codegen/port_platform.h>
+
+#include "src/core/lib/channel/channel_trace.h"
+
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "src/core/lib/channel/channel_trace_registry.h"
+#include "src/core/lib/channel/status_util.h"
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/gpr/useful.h"
+#include "src/core/lib/gprpp/memory.h"
+#include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/surface/channel.h"
+#include "src/core/lib/transport/connectivity_state.h"
+#include "src/core/lib/transport/error_utils.h"
+
+namespace grpc_core {
+
+ChannelTrace::TraceEvent::TraceEvent(
+    Severity severity, grpc_slice data,
+    RefCountedPtr<ChannelTrace> referenced_tracer, ReferencedType type)
+    : severity_(severity),
+      data_(data),
+      timestamp_(grpc_millis_to_timespec(grpc_core::ExecCtx::Get()->Now(),
+                                         GPR_CLOCK_REALTIME)),
+      next_(nullptr),
+      referenced_tracer_(std::move(referenced_tracer)),
+      referenced_type_(type) {}
+
+ChannelTrace::TraceEvent::TraceEvent(Severity severity, grpc_slice data)
+    : severity_(severity),
+      data_(data),
+      timestamp_(grpc_millis_to_timespec(grpc_core::ExecCtx::Get()->Now(),
+                                         GPR_CLOCK_REALTIME)),
+      next_(nullptr) {}
+
+ChannelTrace::TraceEvent::~TraceEvent() { grpc_slice_unref_internal(data_); }
+
+ChannelTrace::ChannelTrace(size_t max_events)
+    : channel_uuid_(-1),
+      num_events_logged_(0),
+      list_size_(0),
+      max_list_size_(max_events),
+      head_trace_(nullptr),
+      tail_trace_(nullptr) {
+  if (max_list_size_ == 0) return;  // tracing is disabled if max_events == 0
+  gpr_mu_init(&tracer_mu_);
+  channel_uuid_ = grpc_channel_trace_registry_register_channel_trace(this);
+  time_created_ = grpc_millis_to_timespec(grpc_core::ExecCtx::Get()->Now(),
+                                          GPR_CLOCK_REALTIME);
+}
+
+ChannelTrace::~ChannelTrace() {
+  if (max_list_size_ == 0) return;  // tracing is disabled if max_events == 0
+  TraceEvent* it = head_trace_;
+  while (it != nullptr) {
+    TraceEvent* to_free = it;
+    it = it->next();
+    Delete<TraceEvent>(to_free);
+  }
+  grpc_channel_trace_registry_unregister_channel_trace(channel_uuid_);
+  gpr_mu_destroy(&tracer_mu_);
+}
+
+intptr_t ChannelTrace::GetUuid() const { return channel_uuid_; }
+
+void ChannelTrace::AddTraceEventHelper(TraceEvent* new_trace_event) {
+  ++num_events_logged_;
+  // first event case
+  if (head_trace_ == nullptr) {
+    head_trace_ = tail_trace_ = new_trace_event;
+  }
+  // regular event add case
+  else {
+    tail_trace_->set_next(new_trace_event);
+    tail_trace_ = tail_trace_->next();
+  }
+  ++list_size_;
+  // maybe garbage collect the end
+  if (list_size_ > max_list_size_) {
+    TraceEvent* to_free = head_trace_;
+    head_trace_ = head_trace_->next();
+    Delete<TraceEvent>(to_free);
+    --list_size_;
+  }
+}
+
+void ChannelTrace::AddTraceEvent(Severity severity, grpc_slice data) {
+  if (max_list_size_ == 0) return;  // tracing is disabled if max_events == 0
+  AddTraceEventHelper(New<TraceEvent>(severity, data));
+}
+
+void ChannelTrace::AddTraceEventReferencingChannel(
+    Severity severity, grpc_slice data,
+    RefCountedPtr<ChannelTrace> referenced_tracer) {
+  if (max_list_size_ == 0) return;  // tracing is disabled if max_events == 0
+  // create and fill up the new event
+  AddTraceEventHelper(
+      New<TraceEvent>(severity, data, std::move(referenced_tracer), Channel));
+}
+
+void ChannelTrace::AddTraceEventReferencingSubchannel(
+    Severity severity, grpc_slice data,
+    RefCountedPtr<ChannelTrace> referenced_tracer) {
+  if (max_list_size_ == 0) return;  // tracing is disabled if max_events == 0
+  // create and fill up the new event
+  AddTraceEventHelper(New<TraceEvent>(
+      severity, data, std::move(referenced_tracer), Subchannel));
+}
+
+namespace {
+
+// returns an allocated string that represents tm according to RFC-3339, and,
+// more specifically, follows:
+// https://developers.google.com/protocol-buffers/docs/proto3#json
+//
+// "Uses RFC 3339, where generated output will always be Z-normalized and uses
+// 0, 3, 6 or 9 fractional digits."
+char* fmt_time(gpr_timespec tm) {
+  char time_buffer[35];
+  char ns_buffer[11];  // '.' + 9 digits of precision
+  struct tm* tm_info = localtime((const time_t*)&tm.tv_sec);
+  strftime(time_buffer, sizeof(time_buffer), "%Y-%m-%dT%H:%M:%S", tm_info);
+  snprintf(ns_buffer, 11, ".%09d", tm.tv_nsec);
+  // This loop trims off trailing zeros by inserting a null character that the
+  // right point. We iterate in chunks of three because we want 0, 3, 6, or 9
+  // fractional digits.
+  for (int i = 7; i >= 1; i -= 3) {
+    if (ns_buffer[i] == '0' && ns_buffer[i + 1] == '0' &&
+        ns_buffer[i + 2] == '0') {
+      ns_buffer[i] = '\0';
+      // Edge case in which all fractional digits were 0.
+      if (i == 1) {
+        ns_buffer[0] = '\0';
+      }
+    } else {
+      break;
+    }
+  }
+  char* full_time_str;
+  gpr_asprintf(&full_time_str, "%s%sZ", time_buffer, ns_buffer);
+  return full_time_str;
+}
+
+const char* severity_string(ChannelTrace::Severity severity) {
+  switch (severity) {
+    case ChannelTrace::Severity::Info:
+      return "CT_INFO";
+    case ChannelTrace::Severity::Warning:
+      return "CT_WARNING";
+    case ChannelTrace::Severity::Error:
+      return "CT_ERROR";
+    default:
+      GPR_UNREACHABLE_CODE(return "CT_UNKNOWN");
+  }
+}
+
+}  // anonymous namespace
+
+void ChannelTrace::TraceEvent::RenderTraceEvent(grpc_json* json) const {
+  grpc_json* json_iterator = nullptr;
+  json_iterator = grpc_json_create_child(json_iterator, json, "description",
+                                         grpc_slice_to_c_string(data_),
+                                         GRPC_JSON_STRING, true);
+  json_iterator = grpc_json_create_child(json_iterator, json, "severity",
+                                         severity_string(severity_),
+                                         GRPC_JSON_STRING, false);
+  json_iterator =
+      grpc_json_create_child(json_iterator, json, "timestamp",
+                             fmt_time(timestamp_), GRPC_JSON_STRING, true);
+  if (referenced_tracer_ != nullptr) {
+    char* uuid_str;
+    gpr_asprintf(&uuid_str, "%" PRIdPTR, referenced_tracer_->channel_uuid_);
+    grpc_json* child_ref = grpc_json_create_child(
+        json_iterator, json,
+        (referenced_type_ == Channel) ? "channelRef" : "subchannelRef", nullptr,
+        GRPC_JSON_OBJECT, false);
+    json_iterator = grpc_json_create_child(
+        nullptr, child_ref,
+        (referenced_type_ == Channel) ? "channelId" : "subchannelId", uuid_str,
+        GRPC_JSON_STRING, true);
+    json_iterator = child_ref;
+  }
+}
+
+char* ChannelTrace::RenderTrace() const {
+  if (!max_list_size_)
+    return nullptr;  // tracing is disabled if max_events == 0
+  grpc_json* json = grpc_json_create(GRPC_JSON_OBJECT);
+  char* num_events_logged_str;
+  gpr_asprintf(&num_events_logged_str, "%" PRId64, num_events_logged_);
+  grpc_json* json_iterator = nullptr;
+  json_iterator =
+      grpc_json_create_child(json_iterator, json, "numEventsLogged",
+                             num_events_logged_str, GRPC_JSON_STRING, true);
+  json_iterator =
+      grpc_json_create_child(json_iterator, json, "creationTime",
+                             fmt_time(time_created_), GRPC_JSON_STRING, true);
+  grpc_json* events = grpc_json_create_child(json_iterator, json, "events",
+                                             nullptr, GRPC_JSON_ARRAY, false);
+  json_iterator = nullptr;
+  TraceEvent* it = head_trace_;
+  while (it != nullptr) {
+    json_iterator = grpc_json_create_child(json_iterator, events, nullptr,
+                                           nullptr, GRPC_JSON_OBJECT, false);
+    it->RenderTraceEvent(json_iterator);
+    it = it->next();
+  }
+  char* json_str = grpc_json_dump_to_string(json, 0);
+  grpc_json_destroy(json);
+  return json_str;
+}
+
+}  // namespace grpc_core