add XLOGF_EVERY_MS helper

Summary: Similar to XLOG_EVERY_MS but for formatted messages.

Reviewed By: yfeldblum

Differential Revision: D26296133

fbshipit-source-id: 92d2e240d70cf40b903f19b0350c6d9cc0daa1fb

folly/logging/test/XlogTest.cpp

@@ -357,7 +357,7 @@ TEST_F(XlogTest, rateLimiting) {
           "msg 0", "msg 8", "msg 16", "msg 24", "msg 32", "msg 40", "msg 48"));
   handler->clearMessages();
 
-  // Test XLOG_EVERY_MS and XLOG_N_PER_MS
+  // Test XLOG_EVERY_MS, XLOGF_EVERY_MS and XLOG_N_PER_MS
   // We test these together to minimize the number of sleep operations.
   for (size_t n = 0; n < 10; ++n) {
     // Integer arguments are treated as millisecond
@@ -367,6 +367,10 @@ TEST_F(XlogTest, rateLimiting) {
     XLOG_EVERY_MS(DBG1, 100ms, "ms arg ", n);
     XLOG_EVERY_MS(DBG1, 1s, "s arg ", n);
 
+    // Use XLOGF_EVERY_MS
+    XLOGF_EVERY_MS(DBG1, 100, "fmt arg {}", n);
+    XLOGF_EVERY_MS(DBG1, 100ms, "fmt ms arg {}", n);
+
     // Use XLOG_N_PER_MS() too
     XLOG_N_PER_MS(DBG1, 2, 100, "2x int arg ", n);
     XLOG_N_PER_MS(DBG1, 1, 100ms, "1x ms arg ", n);
@@ -383,6 +387,8 @@ TEST_F(XlogTest, rateLimiting) {
           "int arg 0",
           "ms arg 0",
           "s arg 0",
+          "fmt arg 0",
+          "fmt ms arg 0",
           "2x int arg 0",
           "1x ms arg 0",
           "3x s arg 0",
@@ -391,6 +397,8 @@ TEST_F(XlogTest, rateLimiting) {
           "3x s arg 2",
           "int arg 6",
           "ms arg 6",
+          "fmt arg 6",
+          "fmt ms arg 6",
           "2x int arg 6",
           "1x ms arg 6",
           "2x int arg 7",

folly/logging/xlog.h

@@ -114,6 +114,24 @@
       }(),                                                               \
       ##__VA_ARGS__)
 
+/**
+ * Similar to XLOGF(...) except only log a message every @param ms
+ * milliseconds.
+ *
+ * Note that this is threadsafe.
+ */
+#define XLOGF_EVERY_MS(level, ms, fmt, arg1, ...)                        \
+  XLOGF_IF(                                                              \
+      level,                                                             \
+      [] {                                                               \
+        static ::folly::logging::IntervalRateLimiter                     \
+            folly_detail_xlog_limiter(1, std::chrono::milliseconds(ms)); \
+        return folly_detail_xlog_limiter.check();                        \
+      }(),                                                               \
+      fmt,                                                               \
+      arg1,                                                              \
+      ##__VA_ARGS__)
+
 namespace folly {
 namespace detail {