Resuscitate https://github.com/status-im/nim-codex/pull/251 except for (#358)

A) renaming to --repo-kind which makes more sense in the current code
and B) without a working cacheStore (yet)

Tagging related https://github.com/status-im/nim-codex/issues/357

README.md

@@ -54,6 +54,7 @@ The following options are available:
      --max-peers            The maximum number of peers to connect to [=160].
      --agent-string         Node agent string which is used as identifier in network [=Codex].
  -p, --api-port             The REST Api port [=8080].
+     --repo-kind            backend for main repo store (fs, sqlite) [=fs].
  -q, --storage-quota        The size of the total storage quota dedicated to the node [=8589934592].
  -t, --block-ttl            Default block timeout in seconds - 0 disables the ttl [=86400].
  -c, --cache-size           The size in MiB of the block cache, 0 disables the cache - might help on slow

codex/codex.nim

@@ -158,9 +158,14 @@ proc new*(T: type CodexServer, config: CodexConf, privateKey: CodexPrivateKey):
     wallet = WalletRef.new(EthPrivateKey.random())
     network = BlockExcNetwork.new(switch)
 
+    repoData = case config.repoKind
+                of repoFS: Datastore(FSDatastore.new($config.dataDir, depth = 5)
+                  .expect("Should create repo file data store!"))
+                of repoSQLite: Datastore(SQLiteDatastore.new($config.dataDir)
+                  .expect("Should create repo SQLite data store!"))
+
     repoStore = RepoStore.new(
-      repoDs = Datastore(FSDatastore.new($config.dataDir, depth = 5)
-        .expect("Should create repo data store!")),
+      repoDs = repoData,
       metaDs = SQLiteDatastore.new(config.dataDir / CodexMetaNamespace)
         .expect("Should create meta data store!"),
       quotaMaxBytes = config.storageQuota.uint,

codex/conf.nim

@@ -46,6 +46,10 @@ type
     Json = "json"
     None = "none"
 
+  RepoKind* = enum
+    repoFS = "fs"
+    repoSQLite = "sqlite"
+
   CodexConf* = object
     logLevel* {.
       defaultValue: "INFO"
@@ -151,6 +155,12 @@ type
         name: "api-port"
         abbr: "p" }: int
 
+      repoKind* {.
+        desc: "backend for main repo store (fs, sqlite)"
+        defaultValueDesc: "fs"
+        defaultValue: repoFS
+        name: "repo-kind" }: RepoKind
+
       storageQuota* {.
         desc: "The size of the total storage quota dedicated to the node"
         defaultValue: DefaultQuotaBytes