From 96b18cfce311cfbfb3b66a9d41f4d8e217a1be6f Mon Sep 17 00:00:00 2001
From: andri lim <jangko128@gmail.com>
Date: Thu, 27 Dec 2018 09:59:06 +0700
Subject: [PATCH] add select_backend module

---
 nimbus/db/select_backend.nim  | 10 ++++++++++
 nimbus/nimbus.nim             | 11 +----------
 tests/persistBlockTestGen.nim | 11 +----------
 tests/tracerTestGen.nim       | 11 +----------
 4 files changed, 13 insertions(+), 30 deletions(-)
 create mode 100644 nimbus/db/select_backend.nim

diff --git a/nimbus/db/select_backend.nim b/nimbus/db/select_backend.nim
new file mode 100644
index 000000000..29680461c
--- /dev/null
+++ b/nimbus/db/select_backend.nim
@@ -0,0 +1,10 @@
+const nimbus_db_backend {.strdefine.} = "rocksdb"
+
+when nimbus_db_backend == "sqlite":
+  import ./backends/sqlite_backend as database_backend
+elif nimbus_db_backend == "rocksdb":
+  import ./backends/rocksdb_backend as database_backend
+else:
+  import ./backends/lmdb_backend as database_backend
+
+export database_backend
diff --git a/nimbus/nimbus.nim b/nimbus/nimbus.nim
index c6fc46846..2e97dd9ed 100644
--- a/nimbus/nimbus.nim
+++ b/nimbus/nimbus.nim
@@ -8,22 +8,13 @@
 # those terms.
 
 import
-  os, strutils, net, eth_common, db/[storage_types, db_chain],
+  os, strutils, net, eth_common, db/[storage_types, db_chain, select_backend],
   asyncdispatch2, json_rpc/rpcserver, eth_keys, chronicles,
   eth_p2p, eth_p2p/rlpx_protocols/[eth_protocol, les_protocol],
   eth_p2p/blockchain_sync,
   config, genesis, rpc/[common, p2p, debug, whisper], p2p/chain,
   eth_trie/db
 
-const nimbus_db_backend {.strdefine.} = "rocksdb"
-
-when nimbus_db_backend == "sqlite":
-  import ../nimbus/db/backends/sqlite_backend
-elif nimbus_db_backend == "rocksdb":
-  import ../nimbus/db/backends/rocksdb_backend
-else:
-  import ../nimbus/db/backends/lmdb_backend
-
 ## TODO:
 ## * No IPv6 support
 ## * No multiple bind addresses support
diff --git a/tests/persistBlockTestGen.nim b/tests/persistBlockTestGen.nim
index 11718be40..ff0fd9f00 100644
--- a/tests/persistBlockTestGen.nim
+++ b/tests/persistBlockTestGen.nim
@@ -1,18 +1,9 @@
 import
   json, os, eth_common, stint, chronicles, byteutils, nimcrypto, rlp,
-  eth_trie/[db], ../nimbus/db/[db_chain, capturedb, storage_types],
+  eth_trie/[db], ../nimbus/db/[db_chain, capturedb, storage_types, select_backend],
   ../nimbus/[tracer, vm_types, config],
   ../nimbus/p2p/chain
 
-const nimbus_db_backend {.strdefine.} = "rocksdb"
-
-when nimbus_db_backend == "sqlite":
-  import ../nimbus/db/backends/sqlite_backend
-elif nimbus_db_backend == "rocksdb":
-  import ../nimbus/db/backends/rocksdb_backend
-else:
-  import ../nimbus/db/backends/lmdb_backend
-
 proc putCanonicalHead(chainDB: BaseChainDB, header: BlockHeader) =
   var headerHash = rlpHash(header)
   chainDB.db.put(genericHashKey(headerHash).toOpenArray, rlp.encode(header))
diff --git a/tests/tracerTestGen.nim b/tests/tracerTestGen.nim
index ec5297a33..b778ea4ef 100644
--- a/tests/tracerTestGen.nim
+++ b/tests/tracerTestGen.nim
@@ -1,17 +1,8 @@
 import
   json, os, eth_common, stint, chronicles, byteutils, nimcrypto,
-  eth_trie/[db], ../nimbus/db/[db_chain, capturedb],
+  eth_trie/[db], ../nimbus/db/[db_chain, capturedb, select_backend],
   ../nimbus/[tracer, vm_types, config]
 
-const nimbus_db_backend {.strdefine.} = "rocksdb"
-
-when nimbus_db_backend == "sqlite":
-  import ../nimbus/db/backends/sqlite_backend
-elif nimbus_db_backend == "rocksdb":
-  import ../nimbus/db/backends/rocksdb_backend
-else:
-  import ../nimbus/db/backends/lmdb_backend
-
 proc dumpTest(chainDB: BaseChainDB, blockNumber: int) =
   let
     blockNumber = blockNumber.u256