Prepare clickhouse-proxy PoC

cabal.project

@@ -2,6 +2,7 @@ packages:
     ./library
     ./ecosystem/tls
     ./ecosystem/eventlog2ch
+    ./ecosystem/PoC-clickhouse-proxy
     ./contribution
     ./contribution/modules/protocol-docs
     ./contribution/modules/visits

ecosystem/PoC-clickhouse-proxy/ClickHouseProxy/TcpServer.hs

@@ -0,0 +1,88 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE OverloadedRecordDot #-}
+module ClickHouseProxy.TcpServer (
+  runTcpServer
+) where
+
+import ClickHaskell (ToChType (..))
+import ClickHaskell.Internal
+import ClickHaskell.Protocol (ClientPacket (..), ExceptionPacket (..), HelloPacket (..), Serializable (..), ServerPacket (..))
+import Control.Concurrent (forkFinally)
+import Control.Exception as E (bracket, bracketOnError)
+import Control.Monad (forever, void)
+import Data.Binary (Get)
+import Data.Binary.Get (Decoder (..), runGetIncremental)
+import Data.ByteString as BS (ByteString)
+import Data.ByteString.Char8 as BS (putStrLn)
+import Data.ByteString.Char8 as BS8 (pack)
+import Data.List.NonEmpty as NE (head)
+import Network.Socket
+
+
+runTcpServer :: IO ()
+runTcpServer =
+  runTCPServer Nothing "9000" \sock -> do
+    BS.putStrLn "Opening connection"
+    buffer <- mkBuffer =<< defaultMkBufferArgs "" sock
+    talk buffer
+  where
+  talk buffer = do
+    packet <- readBuffer buffer (deserialize @ClientPacket 54459)
+    case packet of
+      Hello hello -> do
+        Prelude.putStrLn $
+          "client: "               <> show hello.client_name          <> " " <>
+          "client_version_major: " <> show hello.client_version_major <> " " <>
+          "client_version_minor: " <> show hello.client_version_minor <> " " <>
+          "tcp_protocol_version: " <> "54459"                         <> " " <>
+          "default_database: "     <> show hello.default_database     <> " " <>
+          "user: "                 <> show hello.user                 <> " " <>
+          "pass: "                 <> show hello.pass                 <> " " <>
+          ""
+        writeConn buffer
+          . serialize 54459
+          $ Exception MkExceptionPacket{
+              code        = 0,
+              name        = toChType @_ @ByteString $ BS8.pack "Test exception",
+              message     = toChType @_ @ByteString $ BS8.pack "\"Hello, World!\"",
+              stack_trace = toChType @_ @ByteString $ BS8.pack "",
+              nested      = 0
+            }
+      _other -> error "Unexpected packet"
+
+
+runTCPServer :: Maybe HostName -> ServiceName -> (Socket -> IO a) -> IO a
+runTCPServer mhost port server = do
+    addr <- resolve
+    E.bracket (open addr) close loop
+  where
+  resolve = do
+    let hints = defaultHints {
+          addrFlags = [AI_PASSIVE],
+          addrSocketType = Stream
+        }
+    NE.head <$> getAddrInfo (Just hints) mhost (Just port)
+  open addr =
+    E.bracketOnError (openSocket addr) close $ \sock -> do
+      setSocketOption sock ReuseAddr 1
+      withFdSocket sock setCloseOnExecIfNeeded
+      bind sock $ addrAddress addr
+      listen sock 1024
+      return sock
+  loop sock =
+    forever $ E.bracketOnError (accept sock) (close . fst)
+      $ \(conn, _peer) -> void $
+          forkFinally (server conn) (const $ gracefulClose conn 5000)
+
+
+readBuffer :: Buffer -> Get a -> IO a
+readBuffer MkBuffer{readBuff, writeBuff} parser = runBufferReader (runGetIncremental parser)
+  where
+  runBufferReader :: Decoder packet -> IO packet
+  runBufferReader dec = case dec of
+    (Partial decoder) -> readBuff >>= runBufferReader . decoder . Just
+    (Done leftover _consumed packet) -> packet <$ writeBuff leftover
+    (Fail _leftover _consumed msg) -> error ("Deserialization error: " <> msg)

ecosystem/PoC-clickhouse-proxy/LICENSE

@@ -0,0 +1,28 @@
+BSD 3-Clause License
+
+Copyright (c) 2026, Dmitry Kovalev
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

ecosystem/PoC-clickhouse-proxy/README.md

@@ -0,0 +1 @@
+# clickhouse-proxy

ecosystem/PoC-clickhouse-proxy/clickhouse-proxy.cabal

@@ -0,0 +1,43 @@
+cabal-version: 3.0
+
+name:         clickhouse-proxy
+version:      0.1
+author:       Dmitry Kovalev
+maintainer:   Dmitry Kovalev
+category:     ClickHouse
+synopsis:     ClickHouse proxy
+description:  ClickHouse TCP protocol proxy
+homepage:     https://github.com/KovalevDima/clickhouse-proxy
+bug-reports:  https://github.com/KovalevDima/clickhouse-proxy
+license:      BSD-3-Clause
+license-file: LICENSE
+copyright:    2026 Dmitry Kovalev
+build-type:   Simple
+
+extra-doc-files:
+  README.md
+
+source-repository head
+  type: git
+  location: https://github.com/KovalevDima/clickhouse-proxy
+
+executable clickhouse-proxy
+  main-is: clickhouse-proxy.hs
+  hs-source-dirs: .
+  ghc-options:
+    -Wall
+    -Wunused-packages
+  build-depends:
+    -- Internal dependencies
+    ClickHaskell,
+    -- GHC included libraries
+    base >= 4.7 && <5,
+    bytestring,
+    binary,
+    -- External dependencies
+    network < 4,
+  other-modules:
+    ClickHouseProxy.TcpServer
+  default-language: Haskell2010
+  default-extensions:
+    BlockArguments

ecosystem/PoC-clickhouse-proxy/clickhouse-proxy.hs

@@ -0,0 +1,8 @@
+module Main where
+
+import ClickHouseProxy.TcpServer (runTcpServer)
+
+main :: IO ()
+main = do
+  putStrLn "Starting server"
+  runTcpServer

library/ClickHaskell.cabal

@@ -34,6 +34,7 @@ Library
   Exposed-Modules:
     ClickHaskell
     ClickHaskell.Protocol
+    ClickHaskell.Internal
   Other-Modules:
     ClickHaskell.Connection
     ClickHaskell.Protocol.Client

library/ClickHaskell/Internal.hs

@@ -0,0 +1,8 @@
+module ClickHaskell.Internal (
+  Buffer(..),
+  mkBuffer,
+  defaultMkBufferArgs,
+) where
+
+-- Internal
+import ClickHaskell.Connection