Added random seed to objcfg to make server shuffling reproducable

xrootd · Aug 25, 2022 · 839cfdb · 839cfdb
1 parent 92bd329
commit 839cfdb
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Showing 3 changed files with 8 additions and 3 deletions.
diff --git a/src/XrdEc/XrdEcObjCfg.hh b/src/XrdEc/XrdEcObjCfg.hh
@@ -17,6 +17,7 @@
 #include <vector>
 #include <sstream>
 #include <iomanip>
+#include <chrono>
 
 namespace XrdEc
 {
@@ -46,6 +47,7 @@ namespace XrdEc
         nomtfile( nomtfile )
       {
         digest = usecrc32c ? crc32c : isal_crc32;
+        seed = std::chrono::system_clock::now().time_since_epoch().count();
       }
 
       ObjCfg( const ObjCfg &objcfg ) : obj( objcfg.obj ),
@@ -59,7 +61,8 @@ namespace XrdEc
                                        plgr( objcfg.plgr ),
 									   plgrReplace(objcfg.plgrReplace),
                                        digest( objcfg.digest ),
-                                       nomtfile( objcfg.nomtfile )
+                                       nomtfile( objcfg.nomtfile ),
+									   seed( objcfg.seed )
       {
       }
 
@@ -105,6 +108,8 @@ namespace XrdEc
       uint32_t (*digest)(uint32_t, void const*, size_t);
 
       bool nomtfile;
+
+      uint64_t seed; // the seed used for e.g. server shuffling, default set to current time
   };
 }
 

diff --git a/src/XrdEc/XrdEcStrmWriter.cc b/src/XrdEc/XrdEcStrmWriter.cc
@@ -137,7 +137,7 @@ namespace XrdEc
     //-------------------------------------------------------------------------
     // Shuffle the servers so every block has a different placement
     //-------------------------------------------------------------------------
-    static std::default_random_engine random_engine( std::chrono::system_clock::now().time_since_epoch().count() );
+    static std::default_random_engine random_engine( objcfg.seed );
     std::shared_ptr<sync_queue<size_t>> servers = std::make_shared<sync_queue<size_t>>();
     std::vector<size_t> zipid( dataarchs.size() );
     std::iota( zipid.begin(), zipid.end(), 0 );

diff --git a/tests/XrdEcTests/MicroTest.cc b/tests/XrdEcTests/MicroTest.cc
@@ -144,7 +144,7 @@ class MicroTest: public CppUnit::TestCase
     	InitRepair(usecrc32c);
     	uint64_t seed2 = std::chrono::system_clock::now().time_since_epoch().count();
 
-    	XrdCl::DefaultEnv::GetLog()->Debug(XrdCl::XRootDMsg, "Random Seed FileGen: %d, Random Seed Corruption: %d" , seed, seed2);
+    	XrdCl::DefaultEnv::GetLog()->Debug(XrdCl::XRootDMsg, "Random Seed FileGen: %d, Random Seed Corruption: %d, Random Seed ObjCfg: %d" , seed, seed2, objcfg->seed);
 
 		// run the test