expose prometheus metrics in testnet

Author: carbolymer

cardano-testnet/src/Testnet/Defaults.hs

@@ -85,16 +85,19 @@ import qualified Data.Aeson.Key as Aeson
 import qualified Data.Aeson.KeyMap as Aeson
 import           Data.Bifunctor (bimap)
 import qualified Data.Default.Class as DefaultClass
+import           Data.IORef
 import           Data.Proxy
 import           Data.Ratio
 import           Data.Scientific
+import           Data.String
 import           Data.Text (Text)
 import qualified Data.Text as Text
 import           Data.Time (UTCTime)
 import           Data.Word (Word64)
 import           Lens.Micro
 import           Numeric.Natural
 import           System.FilePath ((</>))
+import           System.IO.Unsafe
 
 import           Test.Cardano.Ledger.Core.Rational
 import           Testnet.Start.Types
@@ -174,6 +177,11 @@ defaultConwayGenesis = do
       , cgInitialDReps = mempty
       }
 
+-- TODO REMOVE
+nCounter :: IORef Int
+nCounter = unsafePerformIO $ newIORef 0
+{-# NOINLINE nCounter #-}
+
 -- | The only era supported by cardano-testnet for the moment.
 -- It's important to keep the era parameterization everywhere, for ease of development
 -- when new eras roll out.
@@ -186,7 +194,7 @@ defaultYamlHardforkViaConfig :: ShelleyBasedEra era -> Aeson.KeyMap Aeson.Value
 defaultYamlHardforkViaConfig sbe =
   defaultYamlConfig
     <> tracers
-    <> [("TraceOptions", Aeson.Object mempty)]
+    <> [("TraceOptions", traceOptions)]
     <> protocolVersions sbe
     <> hardforkViaConfig sbe
  where
@@ -300,6 +308,19 @@ defaultYamlHardforkViaConfig sbe =
     , (proxyName (Proxy @TraceTxSubmissionProtocol), False)
     ]
 
+  traceOptions = do
+    let n = unsafePerformIO . atomicModifyIORef nCounter $ \n' -> (n'+1, n')
+    Aeson.object
+      [ "" .= Aeson.object
+        [ "backends" .= Aeson.Array
+          [ "EKGBackend"
+          , "Forwarder"
+          , fromString $ "PrometheusSimple suffix 0.0.0.0 " <> show (12798 + n - 1)
+          , "Stdout HumanFormatColoured"
+          ]
+        ]
+      ]
+
 defaultYamlConfig :: Aeson.KeyMap Aeson.Value
 defaultYamlConfig =
   Aeson.fromList