Move ODSL exporter to cachelib/facebook folder for external use

Summary:
Library who uses CacheLib may not get to modify their clients' service monitoring config. This enables any CacheLib client to directly export stats to ODS. (Same way as CacheBench)

reference to original user question: https://fb.workplace.com/groups/cachelibusers/posts/2314564142064048

Reviewed By: jaesoo-fb

Differential Revision: D47957568

fbshipit-source-id: 64a51fdaeb0b282f82dfd0c33795726463d6464b

Author: Jimmy Lu

cachelib/cachebench/cache/Cache-inl.h

@@ -258,7 +258,7 @@ Cache<Allocator>::Cache(const CacheConfig& config,
     allocatorConfig_.setNvmAdmissionMinTTL(config_.memoryOnlyTTL);
   }
 
-  allocatorConfig_.cacheName = "cachebench";
+  allocatorConfig_.cacheName = kCachebenchCacheName;
 
   bool isRecovered = false;
   if (!allocatorConfig_.cacheDir.empty()) {

cachelib/cachebench/cache/Cache.h

@@ -49,6 +49,8 @@ DECLARE_string(report_ac_memory_usage_stats);
 namespace facebook {
 namespace cachelib {
 namespace cachebench {
+constexpr folly::StringPiece kCachebenchCacheName = "cachebench";
+
 // An admission policy that rejects items that was last accessed more than
 // X seconds ago. This is useful to simulate workloads where we provide a
 // retention (soft) guarantee.

cachelib/cachebench/main.cpp

@@ -28,7 +28,7 @@
 #ifdef CACHEBENCH_FB_ENV
 #include "cachelib/cachebench/facebook/FbDep.h"
 #include "cachelib/cachebench/facebook/fb303/FB303ThriftServer.h"
-#include "cachelib/cachebench/facebook/odsl_exporter/OdslExporter.h"
+#include "cachelib/facebook/odsl_exporter/OdslExporter.h"
 #include "common/init/Init.h"
 #else
 #include <folly/init/Init.h>
@@ -113,6 +113,7 @@ bool checkArgsValidity() {
 }
 
 int main(int argc, char** argv) {
+  using namespace facebook::cachelib;
   using namespace facebook::cachelib::cachebench;
 
 #ifdef CACHEBENCH_FB_ENV
@@ -124,10 +125,10 @@ int main(int argc, char** argv) {
   CacheBenchConfig config(FLAGS_json_test_config,
                           customizeCacheConfigForFacebook,
                           customizeStressorConfigForFacebook);
-  std::unique_ptr<OdslExporter> odslExporter_;
+  std::unique_ptr<util::OdslExporter> odslExporter_;
   std::unique_ptr<FB303ThriftService> fb303_;
   if (FLAGS_fb303_port == 0 && FLAGS_export_to_ods) {
-    odslExporter_ = std::make_unique<OdslExporter>();
+    odslExporter_ = std::make_unique<util::OdslExporter>(kCachebenchCacheName);
   } else if (FLAGS_fb303_port > 0) {
     fb303_ = std::make_unique<FB303ThriftService>(FLAGS_fb303_port);
   }