Make the storage provider configurable, and show it in the info command

Former-commit-id: e201ce622ff3c7832d03c6b5759386f0efc23cdf

src/IStorage.h

@@ -6,6 +6,7 @@ class IStorageFactory
 public:
     virtual ~IStorageFactory() {}
     virtual class IStorage *create(int db) = 0;
+    virtual const char *name() const = 0;
 };
 
 class IStorage

src/config.cpp

@@ -29,10 +29,13 @@
  */
 
 #include "server.h"
+#include "storage/rocksdbfactory.h"
 #include "cluster.h"
 
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <sys/sysinfo.h>
+
 
 const char *KEYDB_SET_VERSION = KEYDB_REAL_VERSION;
 
@@ -212,6 +215,38 @@ void queueLoadModule(sds path, sds *argv, int argc) {
     listAddNodeTail(g_pserver->loadmodule_queue,loadmod);
 }
 
+static bool initializeStorageProvider(sds *argv, int argc, const char **err)
+{
+    bool fResult = false;
+    if (!strcasecmp(argv[0], "flash") && argc == 2)
+    {
+        // Create The Storage Factory (if necessary)
+        g_pserver->m_pstorageFactory = CreateRocksDBStorageFactory(argv[1], cserver.dbnum);
+        fResult = true;
+    }
+
+    if (fResult)
+    {
+        // We need to set max memory to a sane default so keys are actually evicted properly
+        if (g_pserver->maxmemory == 0)
+        {
+            struct sysinfo sys;
+            if (sysinfo(&sys) == 0)
+            {
+                // By default it's half the memory.  This gives sufficient room for background saving
+                g_pserver->maxmemory = sys.totalram / 2;
+                if (g_pserver->maxmemory_policy == MAXMEMORY_NO_EVICTION)
+                    g_pserver->maxmemory_policy = MAXMEMORY_ALLKEYS_LRU;
+            }
+        }
+    }
+    else
+    {
+        *err = "Unknown storage provider";
+    }
+    return fResult;
+}
+
 void loadServerConfigFromString(char *config) {
     const char *err = NULL;
     int linenum = 0, totlines, i;
@@ -802,6 +837,9 @@ void loadServerConfigFromString(char *config) {
             g_fTestMode = yesnotoi(argv[1]);
         } else if (!strcasecmp(argv[0],"rdbfuzz-mode")) {
             // NOP, handled in main
+        } else if (!strcasecmp(argv[0],"storage-provider") && argc >= 2) {
+            if (!initializeStorageProvider(argv+1, argc-1, &err))
+                goto loaderr;
         } else {
             err = "Bad directive or wrong number of arguments"; goto loaderr;
         }

src/server.cpp

@@ -61,7 +61,6 @@
 #include <uuid/uuid.h>
 #include <mutex>
 #include "aelocker.h"
-#include "storage/rocksdbfactory.h"
 
 int g_fTestMode = false;
 
@@ -3016,9 +3015,6 @@ void initServer(void) {
     signal(SIGPIPE, SIG_IGN);
     setupSignalHandlers();
 
-    // Create The Storage Factory (if necessary)
-    g_pserver->m_pstorageFactory = CreateRocksDBStorageFactory("/tmp/rocks.db", cserver.dbnum);
-
     zfree(g_pserver->db);   // initServerConfig created a dummy array, free that now
     g_pserver->db = (redisDb**)zmalloc(sizeof(redisDb*)*cserver.dbnum, MALLOC_LOCAL);
 
@@ -4289,7 +4285,8 @@ sds genRedisInfoString(const char *section) {
             "mem_aof_buffer:%zu\r\n"
             "mem_allocator:%s\r\n"
             "active_defrag_running:%d\r\n"
-            "lazyfree_pending_objects:%zu\r\n",
+            "lazyfree_pending_objects:%zu\r\n"
+            "storage_provider:%s\r\n",
             zmalloc_used,
             hmem,
             g_pserver->cron_malloc_stats.process_rss,
@@ -4329,7 +4326,8 @@ sds genRedisInfoString(const char *section) {
             mh->aof_buffer,
             ZMALLOC_LIB,
             g_pserver->active_defrag_running,
-            lazyfreeGetPendingObjectsCount()
+            lazyfreeGetPendingObjectsCount(),
+            g_pserver->m_pstorageFactory ? g_pserver->m_pstorageFactory->name() : "none"
         );
         freeMemoryOverheadData(mh);
     }