fix: add WithLock to limit concurrency

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

context/readerioeither/bracket.go

@@ -0,0 +1,37 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package readerioeither
+
+import (
+	G "github.com/IBM/fp-go/context/readerioeither/generic"
+	E "github.com/IBM/fp-go/either"
+)
+
+// Bracket makes sure that a resource is cleaned up in the event of an error. The release action is called regardless of
+// whether the body action returns and error or not.
+func Bracket[
+	A, B, ANY any](
+
+	acquire ReaderIOEither[A],
+	use func(A) ReaderIOEither[B],
+	release func(A, E.Either[error, B]) ReaderIOEither[ANY],
+) ReaderIOEither[B] {
+	return G.Bracket[ReaderIOEither[A], ReaderIOEither[B], ReaderIOEither[ANY]](
+		acquire,
+		use,
+		release,
+	)
+}

context/readerioeither/generic/bracket.go

@@ -0,0 +1,53 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package generic
+
+import (
+	"context"
+
+	E "github.com/IBM/fp-go/either"
+	G "github.com/IBM/fp-go/internal/bracket"
+	I "github.com/IBM/fp-go/readerio/generic"
+)
+
+// Bracket makes sure that a resource is cleaned up in the event of an error. The release action is called regardless of
+// whether the body action returns and error or not.
+func Bracket[
+	GA ~func(context.Context) TA,
+	GB ~func(context.Context) TB,
+	GANY ~func(context.Context) TANY,
+
+	TA ~func() E.Either[error, A],
+	TB ~func() E.Either[error, B],
+	TANY ~func() E.Either[error, ANY],
+
+	A, B, ANY any](
+
+	acquire GA,
+	use func(A) GB,
+	release func(A, E.Either[error, B]) GANY,
+) GB {
+	return G.Bracket[GA, GB, GANY, E.Either[error, B], A, B](
+		I.Of[GB, TB, context.Context, E.Either[error, B]],
+		MonadChain[GA, GB, TA, TB, A, B],
+		I.MonadChain[GB, GB, TB, TB, context.Context, E.Either[error, B], E.Either[error, B]],
+		MonadChain[GANY, GB, TANY, TB, ANY, B],
+
+		acquire,
+		use,
+		release,
+	)
+}

context/readerioeither/generic/reader.go

@@ -432,10 +432,10 @@ func FromIOEither[
 
 func FromIO[
 	GRA ~func(context.Context) GIOA,
-	GIOA ~func() E.Either[error, A],
-
 	GIOB ~func() A,
 
+	GIOA ~func() E.Either[error, A],
+
 	A any](t GIOB) GRA {
 	return RIE.FromIO[GRA](t)
 }
@@ -571,7 +571,7 @@ func Timer[
 ](delay time.Duration) GRA {
 	return F.Pipe2(
 		IO.Now[func() time.Time](),
-		FromIO[GRA, GIOA, func() time.Time],
+		FromIO[GRA, func() time.Time],
 		Delay[GRA](delay),
 	)
 }

context/readerioeither/generic/sync.go

@@ -0,0 +1,44 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package generic
+
+import (
+	"context"
+
+	E "github.com/IBM/fp-go/either"
+	F "github.com/IBM/fp-go/function"
+	IO "github.com/IBM/fp-go/io/generic"
+)
+
+// WithLock executes the provided IO operation in the scope of a lock
+func WithLock[
+	GRA ~func(context.Context) GIOA,
+	GIOA ~func() E.Either[error, A],
+	GRCANCEL ~func(context.Context) GIOCANCEL,
+	GIOCANCEL ~func() E.Either[error, context.CancelFunc],
+	A any](lock GRCANCEL) func(fa GRA) GRA {
+
+	type GRANY func(ctx context.Context) func() E.Either[error, any]
+	type IOANY func() any
+
+	return F.Flow2(
+		F.Constant1[context.CancelFunc, GRA],
+		WithResource[GRA, GRCANCEL, GRANY](lock, F.Flow2(
+			IO.FromImpure[IOANY, context.CancelFunc],
+			FromIO[GRANY, IOANY],
+		)),
+	)
+}

context/readerioeither/sync.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2023 IBM Corp.
+// All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package readerioeither
+
+import (
+	"context"
+
+	G "github.com/IBM/fp-go/context/readerioeither/generic"
+)
+
+// WithLock executes the provided IO operation in the scope of a lock
+func WithLock[A any](lock ReaderIOEither[context.CancelFunc]) func(fa ReaderIOEither[A]) ReaderIOEither[A] {
+	return G.WithLock[ReaderIOEither[A]](lock)
+}