README modified, haskell-bee-pgmq README added

README.md

@@ -24,15 +24,18 @@ The library so far contains 3 implementations for brokers:
   (c.f. https://redis.io/glossary/redis-queue/)
 - [**STM**](./haskell-bee-stm) - which uses the `STM`, could be useful for testing
 
+`pgmq` broker so far is assumed to be most stable and complete,
+`redis` and `STM` are considered experimental.
+
 The broker definition uses some more advanced GHC type extensions
 (in particular, [type families](https://wiki.haskell.org/GHC/Type_families))
 at the benefit of having one clear interface for what we expect from the broker.
 
 ### Worker
 
-The worker (defined in [`./src/Async/Worker.hs`]) is completely described by it's `State`.
+The worker (defined in [`./src/Async/Worker.hs`](./src/Async/Worker.hs)) is completely described by it's `State`.
 
-This contains information such as:
+`State` contains information such as:
 - broker instance
 - queue name (one worker is assumed to be assigned to a single queue. If you want more queues, just spawn more workers)
 - actions to be performed on incoming data
@@ -43,6 +46,7 @@ This contains information such as:
   - after timeout occurred
   - after job error
 
+This project doesn't provide worker management utilities.
 
 ## Testing
 

haskell-bee-pgmq/README.md

+# haskell-bee-pgmq
+
+`pgmq` broker implementation for `haskell-bee`.
+
+## Database initialization
+
+Notice that upon broker initialization, this calls `PGMQ.initialize`
+which tries very hard to create the pgmq schema for you.
+
+If you also want to pre-create the database itself, with some given
+user, you can try something like this:
+
+```haskell
+import Shelly qualified as SH
+
+createDBIfNotExists :: Text -> Text -> IO ()
+createDBIfNotExists connStr dbName = do
+  -- For the \gexec trick, see:
+  -- https://stackoverflow.com/questions/18389124/simulate-create-database-if-not-exists-for-postgresql
+  (_res, _ec) <- SH.shelly $ SH.silently $ SH.escaping False $ do
+    let sql = "\"SELECT 'CREATE DATABASE " <> dbName <> "' WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = '" <> dbName <> "')\\gexec\""
+    result <- SH.run "echo" [sql, "|", "psql", "-d", "\"" <> connStr <> "\""]
+    (result,) <$> SH.lastExitCode
+    
+  return ()
+```