feat(postgres): integration of postgres in wakunode2 (#1808)

* Making the wakunode2 to support postgres driver

* driver/builder.nim: controling possible errors when creating the messages table

* postgres_driver.nim: adding protection in getInt and fixing typo

waku/v2/waku_archive/driver/builder.nim

@@ -6,18 +6,21 @@ else:
 
 import
   stew/results,
-  chronicles
+  chronicles,
+  chronos
 import
   ../driver,
   ../../../common/databases/dburl,
   ../../../common/databases/db_sqlite,
   ./sqlite_driver,
   ./sqlite_driver/migrations as archive_driver_sqlite_migrations,
-  ./queue_driver
+  ./queue_driver,
+  ./postgres_driver
 
 export
   sqlite_driver,
-  queue_driver
+  queue_driver,
+  postgres_driver
 
 proc new*(T: type ArchiveDriver,
           url: string,
@@ -69,6 +72,24 @@ proc new*(T: type ArchiveDriver,
 
     return ok(res.get())
 
+  of "postgres":
+    const MaxNumConns = 5 #TODO: we may need to set that from app args (maybe?)
+    let res = PostgresDriver.new(url, MaxNumConns)
+    if res.isErr():
+      return err("failed to init postgres archive driver: " & res.error)
+
+    let driver = res.get()
+
+    try:
+      # The table should exist beforehand.
+      let newTableRes = waitFor driver.createMessageTable()
+      if newTableRes.isErr():
+        return err("error creating table: " & newTableRes.error)
+    except CatchableError:
+      return err("exception creating table: " & getCurrentExceptionMsg())
+
+    return ok(driver)
+
   else:
     debug "setting up in-memory waku archive driver"
     let driver = QueueDriver.new()  # Defaults to a capacity of 25.000 messages

waku/v2/waku_archive/driver/postgres_driver/postgres_driver.nim

@@ -52,7 +52,7 @@ proc new*(T: type PostgresDriver,
 
   return ok(PostgresDriver(connPool: connPoolRes.get()))
 
-proc createMessageTable(s: PostgresDriver):
+proc createMessageTable*(s: PostgresDriver):
                          Future[ArchiveDriverResult[void]] {.async.}  =
 
   let execRes = await s.connPool.exec(createTableQuery())
@@ -238,8 +238,9 @@ proc getInt(s: PostgresDriver,
   if fields.len != 1:
     return err("failed in getRow: Expected one field but got " & $fields.len)
 
-  var retInt: int64
+  var retInt = 0'i64
   try:
+    if fields[0] != "":
       retInt = parseInt(fields[0])
   except ValueError:
     return err("exception in getRow, parseInt: " & getCurrentExceptionMsg())
@@ -269,7 +270,7 @@ method getNewestMessageTimestamp*(s: PostgresDriver):
 
   let intRes = await s.getInt("SELECT MAX(storedAt) FROM messages")
   if intRes.isErr():
-    return err("error in getOldestMessageTimestamp: " & intRes.error)
+    return err("error in getNewestMessageTimestamp: " & intRes.error)
 
   return ok(Timestamp(intRes.get()))