feat(sut): add db module for sqlite dumblog

src/sut/dumblog/dumblog.cabal

@@ -29,14 +29,15 @@ extra-source-files:
 
 library
   build-depends:
-    , base        ^>=4.14.1.0
+    , base           ^>=4.14.1.0
     , binary
     , bytestring
     , containers
     , directory
     , filepath
     , http-types
     , journal
+    , sqlite-simple
     , text
     , time
     , wai
@@ -51,6 +52,7 @@ library
     Dumblog.Journal.StateMachine
     Dumblog.Journal.Types
     Dumblog.Journal.Worker
+    Dumblog.SQLite.DB
     Dumblog.SQLite.Main
 
   hs-source-dirs:   src

src/sut/dumblog/src/Dumblog/SQLite/DB.hs

@@ -0,0 +1,33 @@
+module Dumblog.SQLite.DB where
+
+import Data.ByteString (ByteString)
+import Database.SQLite.Simple
+       ( Connection
+       , Only(Only)
+       , execute
+       , execute_
+       , lastInsertRowId
+       , open
+       , query
+       )
+
+------------------------------------------------------------------------
+
+sQLITE_DB_PATH :: FilePath
+sQLITE_DB_PATH = "/tmp/dumblog.sqlite3"
+
+initDB :: IO Connection
+initDB = do
+  conn <- open sQLITE_DB_PATH
+  execute_ conn "CREATE TABLE IF NOT EXISTS dumblog (ix INTEGER PRIMARY KEY, value BLOB)"
+  return conn
+
+writeDB :: Connection -> ByteString -> IO Int
+writeDB conn bs = do
+  execute conn "INSERT INTO dumblog (value) VALUES (?)" (Only bs)
+  fromIntegral <$> lastInsertRowId conn
+
+readDB :: Connection -> Int -> IO ByteString
+readDB conn ix = do
+  [[bs]] <- query conn "SELECT value from dumblog WHERE ix = ?" (Only ix)
+  return bs