Little typeclass to run two IOs in parallel

ktonga · May 15, 2018 · 824c234 · 824c234
1 parent 40c06f6
commit 824c234
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Showing 4 changed files with 21 additions and 4 deletions.
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
@@ -6,7 +6,7 @@ object Dependencies {
 
   lazy val compile = Seq(
     dep("org.scalaz", "7.2.21", "scalaz-core"),
-    dep("org.scalaz", "2.1.0", "scalaz-ioeffect", "scalaz-ioeffect-cats"),
+    dep("org.scalaz", "2.2.0", "scalaz-ioeffect", "scalaz-ioeffect-cats"),
     dep("com.codecommit", "1.2.1", "shims"),
     dep("co.fs2", "0.10.3", "fs2-core"),
     dep("eu.timepit", "0.8.7", "refined-scalaz"),

diff --git a/src/main/scala/com/brickx/Par.scala b/src/main/scala/com/brickx/Par.scala
@@ -0,0 +1,16 @@
+package com.brickx
+
+import std._
+
+trait Par[F[_]] {
+  def apply2[A, B, C](fa: F[A], fb: F[B])(ff: (A, B) => C): F[C]
+}
+
+object Par {
+  @inline def apply[F[_]](implicit F: Par[F]): Par[F] = F
+
+  implicit def ioPar[E]: Par[IO[E, ?]] = new Par[IO[E, ?]] {
+    override def apply2[A, B, C](fa: IO[E, A], fb: IO[E, B])(ff: (A, B) => C): IO[E, C] =
+      fa.par(fb).map(ff.tupled)
+  }
+}
diff --git a/src/main/scala/com/brickx/autoinvest/Program.scala b/src/main/scala/com/brickx/autoinvest/Program.scala
@@ -22,13 +22,13 @@ object Program {
 
   type ComputeAutoInvest = TradingData => Result[CreateOrderRequest]
 
-  def default[F[_]: Sync](events: Events[F],
+  def default[F[_]: Sync: Par](events: Events[F],
                           trading: Trading[F],
                           db: Db[F],
                           computeAutoInvest: ComputeAutoInvest)(implicit clock: Clock): Program[F] =
     new DefaultProgram(events, trading, db, computeAutoInvest)
 
-  class DefaultProgram[F[_]: Sync](events: Events[F],
+  class DefaultProgram[F[_]: Sync: Par](events: Events[F],
                                    trading: Trading[F],
                                    db: Db[F],
                                    computeAutoInvest: ComputeAutoInvest)(implicit clock: Clock)
@@ -48,7 +48,7 @@ object Program {
     }
 
     private def fetchTradingData(accountId: AccountId): F[(AccountId, Result[TradingData])] =
-      ^(
+      Par[F].apply2(
         trading.getPortfolio(accountId, "today".just),
         trading.getOrderBook("some-prop")
       )(TradingData.apply).attemptR.map((accountId, _))

diff --git a/src/test/scala/com/brickx/autoinvest/ProgramSpec.scala b/src/test/scala/com/brickx/autoinvest/ProgramSpec.scala
@@ -117,4 +117,5 @@ trait Fakes {
     override def savePending(pending: Pending): Task[Unit] =
       IO.point(pendings = pendings :+ pending).toUnit
   }
+
 }