Unify logging facilities. (#3982)

* Unify logging facilities.

* Enhance `ConsoleLogger` to handle different verbosity.
* Override macros from `dmlc`.
* Don't use specialized gamma when building with GPU.
* Remove verbosity cache in monitor.
* Test monitor.
* Deprecate `silent`.
* Fix doc and messages.
* Fix python test.
* Fix silent tests.

tests/cpp/common/test_device_helpers.cu

@@ -5,7 +5,6 @@
 #include <thrust/device_vector.h>
 #include <xgboost/base.h>
 #include "../../../src/common/device_helpers.cuh"
-#include "../../../src/common/timer.h"
 #include "gtest/gtest.h"
 
 struct Shard { int id; };

tests/cpp/common/test_monitor.cc

@@ -0,0 +1,32 @@
+#include <gtest/gtest.h>
+#include <xgboost/logging.h>
+#include <string>
+#include "../../../src/common/timer.h"
+
+namespace xgboost {
+namespace common {
+TEST(Monitor, Basic) {
+  auto run_monitor =
+      []() {
+        Monitor monitor_;
+        monitor_.Init("Monitor test");
+        monitor_.Start("basic");
+        monitor_.Stop("basic");
+      };
+
+  std::map<std::string, std::string> args = {std::make_pair("verbosity", "3")};
+  ConsoleLogger::Configure(args.cbegin(), args.cend());
+  testing::internal::CaptureStderr();
+  run_monitor();
+  std::string output = testing::internal::GetCapturedStderr();
+  ASSERT_NE(output.find("Monitor"), std::string::npos);
+
+  args = {std::make_pair("verbosity", "2")};
+  ConsoleLogger::Configure(args.cbegin(), args.cend());
+  testing::internal::CaptureStderr();
+  run_monitor();
+  output = testing::internal::GetCapturedStderr();
+  ASSERT_EQ(output.find("Monitor"), std::string::npos);
+}
+}  // namespace common
+}  // namespace xgboost

tests/cpp/test_logging.cc

@@ -0,0 +1,47 @@
+#include <map>
+
+#include <gtest/gtest.h>
+#include <xgboost/logging.h>
+
+namespace xgboost {
+
+TEST(Logging, Basic) {
+  std::map<std::string, std::string> args {};
+  args["verbosity"] = "0";  // silent
+  ConsoleLogger::Configure(args.cbegin(), args.cend());
+  testing::internal::CaptureStderr();
+  std::string output = testing::internal::GetCapturedStderr();
+  ASSERT_EQ(output.length(), 0);
+
+  args["verbosity"] = "3";  // debug
+  ConsoleLogger::Configure(args.cbegin(), args.cend());
+
+  testing::internal::CaptureStderr();
+  LOG(WARNING) << "Test Log Warning.";
+  output = testing::internal::GetCapturedStderr();
+  ASSERT_NE(output.find("WARNING"), std::string::npos);
+
+  testing::internal::CaptureStderr();
+  LOG(INFO) << "Test Log Info";
+  output = testing::internal::GetCapturedStderr();
+  ASSERT_NE(output.find("Test Log Info"), std::string::npos);
+
+  testing::internal::CaptureStderr();
+  LOG(DEBUG) << "Test Log Debug.";
+  output = testing::internal::GetCapturedStderr();
+  ASSERT_NE(output.find("DEBUG"), std::string::npos);
+
+  args["silent"] = "True";
+  ConsoleLogger::Configure(args.cbegin(), args.cend());
+  testing::internal::CaptureStderr();
+  LOG(INFO) << "Test Log Info";
+  output = testing::internal::GetCapturedStderr();
+  ASSERT_EQ(output.length(), 0);
+
+  testing::internal::CaptureStderr();
+  LOG(CONSOLE) << "Test Log Console";
+  output = testing::internal::GetCapturedStderr();
+  ASSERT_NE(output.find("Test Log Console"), std::string::npos);
+}
+
+}  // namespace xgboost

tests/cpp/tree/test_gpu_hist.cu

@@ -252,7 +252,7 @@ TEST(GpuHist, EvaluateSplits) {
 
   // Copy cut matrix to device.
   DeviceShard<GradientPairPrecise>::DeviceHistCutMatrix cut;
-  shard->ba.Allocate(0, true,
+  shard->ba.Allocate(0,
                      &(shard->cut_.feature_segments), cmat.row_ptr.size(),
                      &(shard->cut_.min_fvalue), cmat.min_val.size(),
                      &(shard->cut_.gidx_fvalue_map), 24,
@@ -315,7 +315,6 @@ TEST(GpuHist, ApplySplit) {
   int constexpr n_cols = 8;
 
   TrainParam param;
-  param.silent = true;
 
   // Initialize shard
   for (size_t i = 0; i < n_cols; ++i) {
@@ -330,7 +329,7 @@ TEST(GpuHist, ApplySplit) {
   shard->node_sum_gradients.resize(3);
 
   shard->ridx_segments[0] = Segment(0, n_rows);
-  shard->ba.Allocate(0, true, &(shard->ridx), n_rows,
+  shard->ba.Allocate(0, &(shard->ridx), n_rows,
                      &(shard->position), n_rows);
   shard->row_stride = n_cols;
   thrust::sequence(shard->ridx.CurrentDVec().tbegin(),
@@ -367,8 +366,7 @@ TEST(GpuHist, ApplySplit) {
   size_t compressed_size_bytes =
       common::CompressedBufferWriter::CalculateBufferSize(
           row_stride * n_rows, num_symbols);
-  shard->ba.Allocate(0, param.silent,
-                     &(shard->gidx_buffer), compressed_size_bytes);
+  shard->ba.Allocate(0, &(shard->gidx_buffer), compressed_size_bytes);
 
   common::CompressedBufferWriter wr(num_symbols);
   std::vector<int> h_gidx (n_rows * row_stride);