Read options from environment (#881) (#883)

Initialize option flags from environment variables values if they are defined, eg. `BENCHMARK_OUT=<filename>` for `--benchmark_out=<filename>`. Command line flag value always prevails.

Fixes https://github.com/google/benchmark/issues/881.

src/benchmark.cc

@@ -73,14 +73,14 @@ DEFINE_int32(benchmark_repetitions, 1);
 // Report the result of each benchmark repetitions. When 'true' is specified
 // only the mean, standard deviation, and other statistics are reported for
 // repeated benchmarks. Affects all reporters.
-DEFINE_bool( benchmark_report_aggregates_only, false);
+DEFINE_bool(benchmark_report_aggregates_only, false);
 
 // Display the result of each benchmark repetitions. When 'true' is specified
 // only the mean, standard deviation, and other statistics are displayed for
 // repeated benchmarks. Unlike benchmark_report_aggregates_only, only affects
 // the display reporter, but  *NOT* file reporter, which will still contain
 // all the output.
-DEFINE_bool( benchmark_display_aggregates_only, false);
+DEFINE_bool(benchmark_display_aggregates_only, false);
 
 // The format to use for console output.
 // Valid values are 'console', 'json', or 'csv'.
@@ -142,7 +142,7 @@ State::State(IterationCount max_iters, const std::vector<int64_t>& ranges,
   // which must be suppressed.
 #if defined(__INTEL_COMPILER)
 #pragma warning push
-#pragma warning(disable:1875)
+#pragma warning(disable : 1875)
 #elif defined(__GNUC__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Winvalid-offsetof"
@@ -309,7 +309,6 @@ std::unique_ptr<BenchmarkReporter> CreateReporter(
 #pragma GCC diagnostic pop
 #endif
 
-
 }  // end namespace
 
 bool IsZero(double n) {
@@ -318,7 +317,7 @@ bool IsZero(double n) {
 
 ConsoleReporter::OutputOptions GetOutputOptions(bool force_no_color) {
   int output_opts = ConsoleReporter::OO_Defaults;
-  auto is_benchmark_color = [force_no_color] () -> bool {
+  auto is_benchmark_color = [force_no_color]() -> bool {
     if (force_no_color) {
       return false;
     }

src/commandlineflags.cc

@@ -14,6 +14,7 @@
 
 #include "commandlineflags.h"
 
+#include <algorithm>
 #include <cctype>
 #include <cstdlib>
 #include <cstring>
@@ -92,44 +93,40 @@ static std::string FlagToEnvVar(const char* flag) {
 
 }  // namespace
 
-// Reads and returns the Boolean environment variable corresponding to
+bool BoolFromEnv(const char* flag, bool default_val) {
-// the given flag; if it's not set, returns default_value.
-//
-// The value is considered true iff it's not "0".
-bool BoolFromEnv(const char* flag, bool default_value) {
   const std::string env_var = FlagToEnvVar(flag);
-  const char* const string_value = getenv(env_var.c_str());
+  const char* const value_str = getenv(env_var.c_str());
-  return string_value == nullptr ? default_value
+  return value_str == nullptr ? default_val : IsTruthyFlagValue(value_str);
-                                 : strcmp(string_value, "0") != 0;
 }
 
-// Reads and returns a 32-bit integer stored in the environment
+int32_t Int32FromEnv(const char* flag, int32_t default_val) {
-// variable corresponding to the given flag; if it isn't set or
-// doesn't represent a valid 32-bit integer, returns default_value.
-int32_t Int32FromEnv(const char* flag, int32_t default_value) {
   const std::string env_var = FlagToEnvVar(flag);
-  const char* const string_value = getenv(env_var.c_str());
+  const char* const value_str = getenv(env_var.c_str());
-  if (string_value == nullptr) {
+  int32_t value = default_val;
-    // The environment variable is not set.
+  if (value_str == nullptr ||
-    return default_value;
+      !ParseInt32(std::string("Environment variable ") + env_var, value_str,
+                  &value)) {
+    return default_val;
   }
-
+  return value;
-  int32_t result = default_value;
-  if (!ParseInt32(std::string("Environment variable ") + env_var, string_value,
-                  &result)) {
-    std::cout << "The default value " << default_value << " is used.\n";
-    return default_value;
-  }
-
-  return result;
 }
 
-// Reads and returns the string environment variable corresponding to
+double DoubleFromEnv(const char* flag, double default_val) {
-// the given flag; if it's not set, returns default_value.
+  const std::string env_var = FlagToEnvVar(flag);
-const char* StringFromEnv(const char* flag, const char* default_value) {
+  const char* const value_str = getenv(env_var.c_str());
+  double value = default_val;
+  if (value_str == nullptr ||
+      !ParseDouble(std::string("Environment variable ") + env_var, value_str,
+                   &value)) {
+    return default_val;
+  }
+  return value;
+}
+
+const char* StringFromEnv(const char* flag, const char* default_val) {
   const std::string env_var = FlagToEnvVar(flag);
   const char* const value = getenv(env_var.c_str());
-  return value == nullptr ? default_value : value;
+  return value == nullptr ? default_val : value;
 }
 
 // Parses a string as a command line flag.  The string should have
@@ -214,9 +211,18 @@ bool IsFlag(const char* str, const char* flag) {
 }
 
 bool IsTruthyFlagValue(const std::string& value) {
-  if (value.empty()) return true;
+  if (value.size() == 1) {
-  char ch = value[0];
+    char v = value[0];
-  return isalnum(ch) &&
+    return isalnum(v) &&
-         !(ch == '0' || ch == 'f' || ch == 'F' || ch == 'n' || ch == 'N');
+           !(v == '0' || v == 'f' || v == 'F' || v == 'n' || v == 'N');
+  } else if (!value.empty()) {
+    std::string value_lower(value);
+    std::transform(value_lower.begin(), value_lower.end(),
+                   value_lower.begin(), ::tolower);
+    return !(value_lower == "false" || value_lower == "no" ||
+             value_lower == "off");
+  } else
+    return true;
 }
+
 }  // end namespace benchmark

src/commandlineflags.h

@@ -10,22 +10,51 @@
 // Macros for declaring flags.
 #define DECLARE_bool(name) extern bool FLAG(name)
 #define DECLARE_int32(name) extern int32_t FLAG(name)
-#define DECLARE_int64(name) extern int64_t FLAG(name)
 #define DECLARE_double(name) extern double FLAG(name)
 #define DECLARE_string(name) extern std::string FLAG(name)
 
 // Macros for defining flags.
-#define DEFINE_bool(name, default_val) bool FLAG(name) = (default_val)
+#define DEFINE_bool(name, default_val)            \
-#define DEFINE_int32(name, default_val) int32_t FLAG(name) = (default_val)
+  bool FLAG(name) =                               \
-#define DEFINE_int64(name, default_val) int64_t FLAG(name) = (default_val)
+    benchmark::BoolFromEnv(#name, default_val)
-#define DEFINE_double(name, default_val) double FLAG(name) = (default_val)
+#define DEFINE_int32(name, default_val)           \
-#define DEFINE_string(name, default_val) std::string FLAG(name) = (default_val)
+  int32_t FLAG(name) =                            \
+    benchmark::Int32FromEnv(#name, default_val)
+#define DEFINE_double(name, default_val)          \
+  double FLAG(name) =                             \
+    benchmark::DoubleFromEnv(#name, default_val)
+#define DEFINE_string(name, default_val)          \
+  std::string FLAG(name) =                        \
+    benchmark::StringFromEnv(#name, default_val)
 
 namespace benchmark {
-// Parses a bool/Int32/string from the environment variable
+
-// corresponding to the given Google Test flag.
+// Parses a bool from the environment variable
+// corresponding to the given flag.
+//
+// If the variable exists, returns IsTruthyFlagValue() value;  if not,
+// returns the given default value.
 bool BoolFromEnv(const char* flag, bool default_val);
+
+// Parses an Int32 from the environment variable
+// corresponding to the given flag.
+//
+// If the variable exists, returns ParseInt32() value;  if not, returns
+// the given default value.
 int32_t Int32FromEnv(const char* flag, int32_t default_val);
+
+// Parses an Double from the environment variable
+// corresponding to the given flag.
+//
+// If the variable exists, returns ParseDouble();  if not, returns
+// the given default value.
+double DoubleFromEnv(const char* flag, double default_val);
+
+// Parses a string from the environment variable
+// corresponding to the given flag.
+//
+// If variable exists, returns its value;  if not, returns
+// the given default value.
 const char* StringFromEnv(const char* flag, const char* default_val);
 
 // Parses a string for a bool flag, in the form of either
@@ -64,9 +93,11 @@ bool ParseStringFlag(const char* str, const char* flag, std::string* value);
 bool IsFlag(const char* str, const char* flag);
 
 // Returns true unless value starts with one of: '0', 'f', 'F', 'n' or 'N', or
-// some non-alphanumeric character. As a special case, also returns true if
+// some non-alphanumeric character. Also returns false if the value matches
-// value is the empty string.
+// one of 'no', 'false', 'off' (case-insensitive). As a special case, also
+// returns true if value is the empty string.
 bool IsTruthyFlagValue(const std::string& value);
+
 }  // end namespace benchmark
 
 #endif  // BENCHMARK_COMMANDLINEFLAGS_H_

test/commandlineflags_gtest.cc

@@ -34,6 +34,58 @@ TEST(BoolFromEnv, False) {
   ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "0", 1), 0);
   EXPECT_EQ(BoolFromEnv("in_env", true), false);
   unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "N", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "n", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "NO", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "No", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "no", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "F", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "f", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "FALSE", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "False", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "false", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "OFF", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "Off", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "off", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", true), false);
+  unsetenv("BENCHMARK_IN_ENV");
 }
 
 TEST(BoolFromEnv, True) {
@@ -41,9 +93,63 @@ TEST(BoolFromEnv, True) {
   EXPECT_EQ(BoolFromEnv("in_env", false), true);
   unsetenv("BENCHMARK_IN_ENV");
 
-  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "foo", 1), 0);
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "Y", 1), 0);
   EXPECT_EQ(BoolFromEnv("in_env", false), true);
   unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "y", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "YES", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "Yes", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "yes", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "T", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "t", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "TRUE", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "True", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "true", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "ON", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "On", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "on", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+
+#ifndef BENCHMARK_OS_WINDOWS
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "", 1), 0);
+  EXPECT_EQ(BoolFromEnv("in_env", false), true);
+  unsetenv("BENCHMARK_IN_ENV");
+#endif
 }
 
 TEST(Int32FromEnv, NotInEnv) {
@@ -54,7 +160,7 @@ TEST(Int32FromEnv, NotInEnv) {
 TEST(Int32FromEnv, InvalidInteger) {
   ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "foo", 1), 0);
   EXPECT_EQ(Int32FromEnv("in_env", 42), 42);
-  ASSERT_EQ(unsetenv("BENCHMARK_IN_ENV"), 0);
+  unsetenv("BENCHMARK_IN_ENV");
 }
 
 TEST(Int32FromEnv, ValidInteger) {
@@ -63,6 +169,23 @@ TEST(Int32FromEnv, ValidInteger) {
   unsetenv("BENCHMARK_IN_ENV");
 }
 
+TEST(DoubleFromEnv, NotInEnv) {
+  ASSERT_EQ(unsetenv("BENCHMARK_NOT_IN_ENV"), 0);
+  EXPECT_EQ(DoubleFromEnv("not_in_env", 0.51), 0.51);
+}
+
+TEST(DoubleFromEnv, InvalidReal) {
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "foo", 1), 0);
+  EXPECT_EQ(DoubleFromEnv("in_env", 0.51), 0.51);
+  unsetenv("BENCHMARK_IN_ENV");
+}
+
+TEST(DoubleFromEnv, ValidReal) {
+  ASSERT_EQ(setenv("BENCHMARK_IN_ENV", "0.51", 1), 0);
+  EXPECT_EQ(DoubleFromEnv("in_env", 0.71), 0.51);
+  unsetenv("BENCHMARK_IN_ENV");
+}
+
 TEST(StringFromEnv, Default) {
   ASSERT_EQ(unsetenv("BENCHMARK_NOT_IN_ENV"), 0);
   EXPECT_STREQ(StringFromEnv("not_in_env", "foo"), "foo");