Merge pull request #293 from profunktor/feature/logging-stdout-docs

Stdout logging + docs

README.md

@@ -15,7 +15,7 @@ Redis client built on top of [Cats Effect](https://typelevel.org/cats-effect/),
 import cats.effect._
 import cats.implicits._
 import dev.profunktor.redis4cats.Redis
-import dev.profunktor.redis4cats.effect.Log.noop
+import dev.profunktor.redis4cats.effect.Log.Stdout._
 
 object QuickStart extends IOApp {
 

modules/core/src/main/scala/dev/profunktor/redis4cats/effect/Log.scala

@@ -16,12 +16,26 @@
 
 package dev.profunktor.redis4cats.effect
 
-import cats.effect.IO
+import cats.Applicative
+import cats.effect.Sync
 
 /**
   * Typeclass used for internal logging such as acquiring and releasing connections.
   *
-  * You should provide an instance. It is recommended to use `log4cats`.
+  * It is recommended to use `log4cats` for production usage but if you do not want
+  * the extra dependency, you can opt to use either of the simple instances provided.
+  *
+  * If you don't need logging at all, you can use [[Log.NoOp]]
+  *
+  * {{{
+  * import dev.profunktor.redis4cats.effect.Log.NoOp._
+  * }}}
+  *
+  * If you need simple logging to STDOUT for quick debugging, you can use [[Log.Stdout]]
+  *
+  * {{{
+  * import dev.profunktor.redis4cats.effect.Log.Stdout._
+  * }}}
   * */
 trait Log[F[_]] {
   def info(msg: => String): F[Unit]
@@ -31,9 +45,22 @@ trait Log[F[_]] {
 object Log {
   def apply[F[_]](implicit ev: Log[F]): Log[F] = ev
 
-  implicit object noop extends Log[IO] {
-    def info(msg: => String): IO[Unit]  = IO.unit
-    def error(msg: => String): IO[Unit] = IO.unit
+  object NoOp {
+    implicit def instance[F[_]: Applicative]: Log[F] =
+      new Log[F] {
+        def info(msg: => String): F[Unit]  = F.unit
+        def error(msg: => String): F[Unit] = F.unit
+      }
+  }
+
+  object Stdout {
+    implicit def instance[F[_]: Sync]: Log[F] =
+      new Log[F] {
+        def info(msg: => String): F[Unit] =
+          F.delay(Console.out.println(msg))
+        def error(msg: => String): F[Unit] =
+          F.delay(Console.err.println(msg))
+      }
   }
 
 }

modules/tests/src/test/scala/dev/profunktor/redis4cats/Redis4CatsFunSuite.scala

@@ -20,7 +20,7 @@ import cats.effect._
 import cats.implicits._
 import dev.profunktor.redis4cats.connection._
 import dev.profunktor.redis4cats.data.RedisCodec
-import dev.profunktor.redis4cats.effect.Log.noop
+import dev.profunktor.redis4cats.effect.Log.NoOp._
 import munit.FunSuite
 import scala.concurrent.{ Await, ExecutionContext, Future }
 import scala.concurrent.duration.Duration

modules/tests/src/test/scala/dev/profunktor/redis4cats/TestScenarios.scala

@@ -20,7 +20,7 @@ import java.time.Instant
 
 import cats.effect._
 import cats.implicits._
-import dev.profunktor.redis4cats.effect.Log.noop
+import dev.profunktor.redis4cats.effect.Log.NoOp._
 import dev.profunktor.redis4cats.effects._
 import dev.profunktor.redis4cats.hlist._
 import dev.profunktor.redis4cats.pipeline.RedisPipeline

site/docs/effects/index.md

@@ -29,10 +29,26 @@ def apply[F[_]](uri: RedisURI): Resource[F, RedisClient]
 
 ### Logger
 
-In order to create a client and/or connection you must provide a `Log` instance that the library uses for internal logging. You could either create your own or use `log4cats` (recommended). `redis4cats` can derive an instance of `Log[F]` if there is an instance of `Logger[F]` in scope, just need to add the extra dependency `redis4cats-log4cats` and `import dev.profunktor.redis4cats.log4cats._`.
+In order to create a client and/or connection you must provide a `Log` instance that the library uses for internal logging. You could either use `log4cats` (recommended), one of the simpler instances such as `NoOp` and `Stdout`, or roll your own. `redis4cats` can derive an instance of `Log[F]` if there is an instance of `Logger[F]` in scope, just need to add the extra dependency `redis4cats-log4cats` and `import dev.profunktor.redis4cats.log4cats._`.
 
 Take a look at the [examples](https://github.com/profunktor/redis4cats/blob/master/modules/examples/src/main/scala/dev/profunktor/redis4cats/LoggerIOApp.scala) to find out more.
 
+#### Disable logging
+
+If you don't need logging at all, use the following import wherever a `Log` instance is required:
+
+```scala
+// Available for any `Applicative[F]`
+import dev.profunktor.redis4cats.effect.Log.NoOp._
+```
+
+If you need simple logging to STDOUT for quick debugging, you can use the following one:
+
+```scala
+// Available for any `Sync[F]`
+import dev.profunktor.redis4cats.effect.Log.Stdout._
+```
+
 ### Establishing connection
 
 Here's an example of acquiring a client and a connection to the `Strings API`:

site/docs/quickstart.md

@@ -11,7 +11,7 @@ position: 1
 import cats.effect._
 import cats.implicits._
 import dev.profunktor.redis4cats.Redis
-import dev.profunktor.redis4cats.effect.Log.noop // disable logging
+import dev.profunktor.redis4cats.effect.Log.Stdout._
 
 object QuickStart extends IOApp {