Create a first pab-based chain client

hydra-node/hydra-node.cabal

@@ -55,6 +55,7 @@ common project-config
     ScopedTypeVariables
     StandaloneDeriving
     TupleSections
+    TypeApplications
     TypeFamilies
     TypeSynonymInstances
     ViewPatterns
@@ -77,6 +78,7 @@ library
   exposed-modules:
     Hydra.API.Server
     Hydra.Chain
+    Hydra.Chain.ExternalPAB
     Hydra.Chain.ZeroMQ
     Hydra.Network
     Hydra.Network.BroadcastToSelf
@@ -121,6 +123,7 @@ library
     , optparse-applicative
     , ouroboros-network-framework
     , prometheus
+    , req
     , shelley-spec-ledger
     , shelley-spec-ledger-test
     , stm
@@ -163,6 +166,7 @@ test-suite tests
   import: project-config
   hs-source-dirs: test
   other-modules:
+    Hydra.Chain.ExternalPABSpec
     Hydra.Chain.ZeroMQSpec
     Hydra.FireForgetSpec
     Hydra.BehaviorSpec
@@ -192,7 +196,6 @@ test-suite tests
     , QuickCheck
     , quickcheck-instances
     , typed-protocols-examples
-    , HUnit
   build-tool-depends:
     hspec-discover:hspec-discover
   ghc-options:

hydra-node/src/Hydra/Chain/ExternalPAB.hs

@@ -0,0 +1,40 @@
+module Hydra.Chain.ExternalPAB where
+
+import Cardano.Prelude
+import Hydra.Chain (Chain (Chain, postTx))
+import Hydra.HeadLogic (OnChainTx (InitTx))
+import Hydra.Ledger (Tx)
+import Hydra.Logging (Tracer)
+import Network.HTTP.Req (POST (..), ReqBodyJson (..), defaultHttpConfig, http, jsonResponse, port, req, responseBody, responseStatusCode, runReq, (/:))
+
+data ExternalPABLog
+
+withExternalPAB ::
+  Tx tx =>
+  Tracer IO ExternalPABLog ->
+  (OnChainTx tx -> IO ()) ->
+  (Chain tx IO -> IO a) ->
+  IO a
+withExternalPAB _tracer _callback action = do
+  action $ Chain{postTx}
+ where
+  postTx = \case
+    InitTx _ -> loadCid >>= postInitTx
+    tx -> panic $ "should post " <> show tx
+
+  loadCid = readFile "/tmp/W1.cid"
+
+-- TODO(SN): use MonadHttp, but clashes with MonadThrow
+postInitTx :: Text -> IO ()
+postInitTx cid = do
+  runReq defaultHttpConfig $ do
+    res <-
+      req
+        POST
+        (http "127.0.0.1" /: "api" /: "new" /: "contract" /: "instance" /: cid /: "endpoint" /: "init")
+        (ReqBodyJson ())
+        jsonResponse
+        (port 8080)
+    when (responseStatusCode res /= 200) $
+      panic "failed to postInitTx"
+    pure $ responseBody res

hydra-node/test/Hydra/Chain/ExternalPABSpec.hs

@@ -0,0 +1,17 @@
+module Hydra.Chain.ExternalPABSpec where
+
+import Cardano.Prelude
+import Hydra.Chain (Chain (..))
+import Hydra.Chain.ExternalPAB (withExternalPAB)
+import Hydra.HeadLogic (OnChainTx (..))
+import Hydra.Ledger.Mock (MockTx)
+import Hydra.Logging (nullTracer)
+import Test.Hspec.Core.Spec (Spec, describe, it)
+
+spec :: Spec
+spec =
+  describe "ExternalPAB" $ do
+    it "publishes init tx using wallet 1" $ do
+      -- TODO(SN): launch hydra-pab as process
+      withExternalPAB nullTracer (panic "called back") $ \Chain{postTx} ->
+        postTx $ InitTx @MockTx (panic "unused")

hydra-plutus/exe/hydra-pab/Main.hs

@@ -54,7 +54,7 @@ main = void $
 
   activateWallets = forM [alice, bob] $ \w -> do
     (ContractInstanceId cid) <- Simulator.activateContract w HydraContract
-    let fn = 'W' : show (getWallet w) <> ".cid"
+    let fn = "/tmp/W" <> show (getWallet w) <> ".cid"
     liftIO $ writeFile fn $ show cid
     pure fn