Support multiple databases

README.md

@@ -158,7 +158,7 @@ import io.github.gaelrenoux.tranzactio.doobie._
 import javax.sql.DataSource
 import zio._
 
-val dbLayer: ZLayer[Has[DataSource], Nothing, Database] = Database.fromDatasource
+val dbLayer: ZLayer[DataSource, Nothing, Database] = Database.fromDatasource
 ```
 
 
@@ -290,7 +290,7 @@ Database.transaction(???) // es is passed implicitly to the method
 
 ```scala
 val es: ErrorStrategies = ErrorStrategies.retryForeverFixed(10.seconds)
-val dbLayerFromDatasource: ZLayer[Has[DataSource], Nothing, Database] = Database.fromDatasource(es)
+val dbLayerFromDatasource: ZLayer[DataSource, Nothing, Database] = Database.fromDatasource(es)
 ```
 
 #### Defining an ErrorStrategies instance
@@ -329,6 +329,36 @@ val es: ErrorStrategies =
 
 
 
+### Multiple Databases
+
+Some applications use multiple databases.
+In that case, it is necessary to have them be different types in the ZIO environment.
+
+Tranzactio offers a typed database class, called `DatabaseT[_]`.
+You only need to provide a different marker type for each database you use.
+
+```scala
+import io.github.gaelrenoux.tranzactio.doobie._
+import javax.sql.DataSource
+import zio._
+
+trait Db1
+trait Db2
+
+val db1Layer: ZLayer[Any, Nothing, DatabaseT[Db1]] = datasource1Layer >>> Database[Db1].fromDatasource
+val db2Layer: ZLayer[Any, Nothing, DatabaseT[Db2]] = datasource2Layer >>> Database[Db2].fromDatasource
+
+val queries1: ZIO[Connection, DbException, List[String]] = ???
+val zio1: ZIO[DatabaseT[Db1], DbException, List[Person]] = DatabaseT[Db1].transactionOrWiden(queries1)
+val zio2: ZIO[DatabaseT[Db2], DbException, List[Person]] = DatabaseT[Db2].transactionOrWiden(queries1)
+```
+
+When creating the layers for the datasources, don't forget to use `.fresh` when you have sub-layers of the same type on both sides!
+
+You can see a full example in the `examples` submodule (in `LayeredAppMultipleDatabases`).
+
+
+
 ### Single-connection Database
 
 In some cases, you might want to have a `Database` module representing a single connection.
@@ -382,7 +412,7 @@ import zio._
 import zio.interop.catz._
 
 implicit val doobieContext: DbContext = DbContext(logHandler = LogHandler.jdkLogHandler[Task])
-val dbLayer: ZLayer[Has[DataSource], Nothing, Database] = Database.fromDatasource
+val dbLayer: ZLayer[DataSource, Nothing, Database] = Database.fromDatasource
 ```
 
 
@@ -403,7 +433,7 @@ See https://github.com/zio/interop-cats/issues/669 for more details about this i
 
 
 
-### When will tranzactio work with <insert DB library here>?
+### When will tranzactio work with …?
 
 I want to add wrappers around more database access libraries.
 Anorm was the second one I did, next should probably be Quill (based on the popularity of the project on GitHub),

anorm/src/main/scala/io/github/gaelrenoux/tranzactio/anorm/package.scala

@@ -41,4 +41,10 @@ package object anorm extends Wrapper {
     override final def connectionFromJdbc(connection: => JdbcConnection)(implicit trace: Trace): ZIO[Any, Nothing, Connection] =
       ZIO.succeed(connection)
   }
+
+  override final type DatabaseT[M] = DatabaseTBase[M, Connection]
+
+  object DatabaseT extends DatabaseTBase.Companion[Connection, DbContext] {
+    def apply[M: Tag]: Module[M] = new Module[M](Database)
+  }
 }

core/src/main/scala/io/github/gaelrenoux/tranzactio/DatabaseTBase.scala

@@ -0,0 +1,34 @@
+package io.github.gaelrenoux.tranzactio
+
+import zio.{Trace, ZEnvironment, ZIO, ZLayer, Tag}
+
+/**
+ * This is a typed database, to use when you have multiple databases in your application. Simply provide a marker type,
+ * and ZIO will be able to differentiate between multiple DatabaseT[_] types in your environment.
+ * @tparam M Marker type, no instances. */
+class DatabaseTBase[M: Tag, Connection](underlying: DatabaseOps.ServiceOps[Connection]) extends DatabaseOps.ServiceOps[Connection] {
+
+  override def transaction[R, E, A](task: => ZIO[Connection with R, E, A], commitOnFailure: => Boolean)
+    (implicit errorStrategies: ErrorStrategiesRef, trace: Trace): ZIO[R with Any, Either[DbException, E], A] =
+    underlying.transaction[R, E, A](task, commitOnFailure = commitOnFailure)
+
+
+  override def autoCommit[R, E, A](task: => ZIO[Connection with R, E, A])
+    (implicit errorStrategies: ErrorStrategiesRef, trace: Trace): ZIO[R with Any, Either[DbException, E], A] =
+    underlying.autoCommit[R, E, A](task)
+
+}
+
+object DatabaseTBase {
+  trait Companion[Connection, DbContext] {
+    type Module[M] = DatabaseTBase.Module[M, Connection, DbContext]
+
+    def apply[M: Tag]: Module[M]
+  }
+
+  class Module[M: Tag, Connection: Tag, DbContext](underlying: DatabaseModuleBase[Connection, DatabaseOps.ServiceOps[Connection], DbContext])
+    extends DatabaseModuleBase[Connection, DatabaseTBase[M, Connection], DbContext] {
+    override def fromConnectionSource(implicit dbContext: DbContext, trace: Trace): ZLayer[ConnectionSource, Nothing, DatabaseTBase[M, Connection]] =
+      underlying.fromConnectionSource.map(env => ZEnvironment(new DatabaseTBase[M, Connection](env.get)))
+  }
+}

core/src/main/scala/io/github/gaelrenoux/tranzactio/Wrapper.scala

@@ -1,6 +1,6 @@
 package io.github.gaelrenoux.tranzactio
 
-import zio.Trace
+import zio.{Tag, Trace}
 
 
 /** A specific wrapper package for one specific library (e.g. Doobie). */
@@ -31,4 +31,10 @@ trait Wrapper {
   /** Wraps a library-specific query into a TranzactIO. */
   def tzio[A](q: => Query[A])(implicit trace: Trace): TranzactIO[A]
 
+  /** Parameterized type for databases, allowing for multiple databases to be handled */
+  type DatabaseT[M]
+
+  val DatabaseT: DatabaseTBase.Companion[Connection, DbContext] // scalastyle:ignore field.name
+
+
 }

doobie/src/main/scala/io/github/gaelrenoux/tranzactio/doobie/package.scala

@@ -1,11 +1,10 @@
 package io.github.gaelrenoux.tranzactio
 
-import _root_.doobie.free.KleisliInterpreter
 import _root_.doobie.LogHandler
+import _root_.doobie.free.KleisliInterpreter
 import _root_.doobie.util.transactor.{Strategy, Transactor}
 import cats.effect.Resource
-import io.github.gaelrenoux.tranzactio.test.DatabaseModuleTestOps
-import io.github.gaelrenoux.tranzactio.test.NoopJdbcConnection
+import io.github.gaelrenoux.tranzactio.test.{DatabaseModuleTestOps, NoopJdbcConnection}
 import zio.interop.catz._
 import zio.stream.ZStream
 import zio.stream.interop.fs2z._
@@ -76,4 +75,10 @@ package object doobie extends Wrapper {
     implicit val Default: DbContext = DbContext(LogHandler.noop[Task])
   }
 
+  override final type DatabaseT[M] = DatabaseTBase[M, Connection]
+
+  object DatabaseT extends DatabaseTBase.Companion[Connection, DbContext] {
+    def apply[M: Tag]: Module[M] = new Module[M](Database)
+  }
+
 }

examples/src/test/scala/samples/SamplesSpec.scala

@@ -13,12 +13,14 @@ object SamplesSpec extends ZIOSpecDefault {
     suite("SamplesSpec")(
       testApp("Doobie", doobie.LayeredApp),
       testApp("Doobie-Streaming", doobie.LayeredAppStreaming),
-      testApp("Anorm", anorm.LayeredApp)
+      testAppMultipleDatabases("Doobie", doobie.LayeredAppMultipleDatabases),
+      testApp("Anorm", anorm.LayeredApp),
+      testAppMultipleDatabases("Anorm", anorm.LayeredAppMultipleDatabases)
     )
 
   private def testApp(name: String, app: ZIOAppDefault): MySpec =
 
-    test(s"$name LayeredApp prints its progress then the trio") {
+    test(s"$name App prints its progress then the trio") {
       for {
         _ <- app.run.provide(ignoredAppArgs ++ Scope.default)
         output <- TestConsole.output
@@ -31,4 +33,22 @@ object SamplesSpec extends ZIOSpecDefault {
       ))
     }
 
+  private def testAppMultipleDatabases(name: String, app: ZIOAppDefault): MySpec =
+
+    test(s"$name App prints its progress for the trio, then its progress for the mentor, then prints the full team") {
+      for {
+        _ <- app.run.provide(ignoredAppArgs ++ Scope.default)
+        output <- TestConsole.output
+      } yield assertTrue(output == Vector(
+        "Starting the app\n",
+        "Creating the table\n",
+        "Inserting the trio\n",
+        "Reading the trio\n",
+        "Creating the table\n",
+        "Inserting the mentor\n",
+        "Reading the mentor\n",
+        "Buffy Summers, Willow Rosenberg, Alexander Harris, Rupert Giles\n"
+      ))
+    }
+
 }

examples/src/test/scala/samples/anorm/LayeredAppMultipleDatabases.scala

@@ -0,0 +1,79 @@
+package samples.anorm
+
+import io.github.gaelrenoux.tranzactio.{DbException, ErrorStrategies}
+import io.github.gaelrenoux.tranzactio.anorm._
+import samples.{Conf, ConnectionPool, Person}
+import zio._
+
+import javax.sql.DataSource
+
+/** A sample app where all modules are linked through ZLayer. Should run as is (make sure you have com.h2database:h2 in
+ * your dependencies). */
+object LayeredAppMultipleDatabases extends zio.ZIOAppDefault {
+
+  /** Marker trait for the first DB */
+  trait Db1
+
+  /** Marker trait for the second DB */
+  trait Db2
+
+  private val database1: ZLayer[Any, Throwable, DatabaseT[Db1]] = {
+    // Fresh calls are required so that the confs and datasource aren't conflated with the other layer's
+    val conf = Conf.live("samble-anorm-app-1").fresh
+    val dbRecoveryConf: ZLayer[Any, Nothing, ErrorStrategies] = conf >>> ZLayer.fromFunction((_: Conf).dbRecovery).fresh
+    val datasource: ZLayer[Any, Throwable, DataSource] = conf >>> ConnectionPool.live.fresh
+    (datasource ++ dbRecoveryConf) >>> DatabaseT[Db1].fromDatasourceAndErrorStrategies
+  }
+
+  private val database2: ZLayer[Any, Throwable, DatabaseT[Db2]] = {
+    // Fresh calls are required so that the confs and datasource aren't conflated with the other layer's
+    val conf = Conf.live("samble-anorm-app-2").fresh
+    val dbRecoveryConf: ZLayer[Any, Nothing, ErrorStrategies] = conf >>> ZLayer.fromFunction((_: Conf).dbRecovery).fresh
+    val datasource: ZLayer[Any, Throwable, DataSource] = conf >>> ConnectionPool.live.fresh
+    (datasource ++ dbRecoveryConf) >>> DatabaseT[Db2].fromDatasourceAndErrorStrategies
+  }
+
+  private val personQueries = PersonQueries.live
+
+  type AppEnv = DatabaseT[Db1] with DatabaseT[Db2] with PersonQueries
+  private val appEnv = database1 ++ database2 ++ personQueries
+
+  override def run: ZIO[ZIOAppArgs with Scope, Any, Any] =
+    for {
+      _ <- Console.printLine("Starting the app")
+      team <- myApp().provideLayer(appEnv)
+      _ <- Console.printLine(team.mkString(", "))
+    } yield ExitCode(0)
+
+  /** Main code for the application. Results in a big ZIO depending on the AppEnv. */
+  def myApp(): ZIO[PersonQueries with DatabaseT[Db2] with DatabaseT[Db1], DbException, List[Person]] = {
+    val queries1: ZIO[PersonQueries with Connection, DbException, List[Person]] = for {
+      _ <- Console.printLine("Creating the table").orDie
+      _ <- PersonQueries.setup
+      _ <- Console.printLine("Inserting the trio").orDie
+      _ <- PersonQueries.insert(Person("Buffy", "Summers"))
+      _ <- PersonQueries.insert(Person("Willow", "Rosenberg"))
+      _ <- PersonQueries.insert(Person("Alexander", "Harris"))
+      _ <- Console.printLine("Reading the trio").orDie
+      trio <- PersonQueries.list
+    } yield trio
+
+    val queries2: ZIO[PersonQueries with Connection, DbException, List[Person]] = for {
+      _ <- Console.printLine("Creating the table").orDie
+      _ <- PersonQueries.setup
+      _ <- Console.printLine("Inserting the mentor").orDie
+      _ <- PersonQueries.insert(Person("Rupert", "Giles"))
+      _ <- Console.printLine("Reading the mentor").orDie
+      mentor <- PersonQueries.list
+    } yield mentor
+
+    val zTrio: ZIO[PersonQueries with DatabaseT[Db1], DbException, List[Person]] = DatabaseT[Db1].transactionOrWiden(queries1)
+    val zMentor: ZIO[PersonQueries with DatabaseT[Db2], DbException, List[Person]] = DatabaseT[Db2].transactionOrWiden(queries2)
+
+    for {
+      trio <- zTrio
+      mentor <- zMentor
+    } yield trio ++ mentor
+  }
+
+}

examples/src/test/scala/samples/doobie/LayeredAppMultipleDatabases.scala

@@ -0,0 +1,78 @@
+package samples.doobie
+
+import io.github.gaelrenoux.tranzactio.{DbException, ErrorStrategies}
+import io.github.gaelrenoux.tranzactio.doobie._
+import samples.{Conf, ConnectionPool, Person}
+import zio._
+
+import javax.sql.DataSource
+
+/** A sample app with two databases for different set of queries. */
+object LayeredAppMultipleDatabases extends zio.ZIOAppDefault {
+
+  /** Marker trait for the first DB */
+  trait Db1
+
+  /** Marker trait for the second DB */
+  trait Db2
+
+  private val database1: ZLayer[Any, Throwable, DatabaseT[Db1]] = {
+    // Fresh calls are required so that the confs and datasource aren't conflated with the other layer's
+    val conf = Conf.live("samble-doobie-app-1").fresh
+    val dbRecoveryConf: ZLayer[Any, Nothing, ErrorStrategies] = conf >>> ZLayer.fromFunction((_: Conf).dbRecovery).fresh
+    val datasource: ZLayer[Any, Throwable, DataSource] = conf >>> ConnectionPool.live.fresh
+    (datasource ++ dbRecoveryConf) >>> DatabaseT[Db1].fromDatasourceAndErrorStrategies
+  }
+
+  private val database2: ZLayer[Any, Throwable, DatabaseT[Db2]] = {
+    // Fresh calls are required so that the confs and datasource aren't conflated with the other layer's
+    val conf = Conf.live("samble-doobie-app-2").fresh
+    val dbRecoveryConf: ZLayer[Any, Nothing, ErrorStrategies] = conf >>> ZLayer.fromFunction((_: Conf).dbRecovery).fresh
+    val datasource: ZLayer[Any, Throwable, DataSource] = conf >>> ConnectionPool.live.fresh
+    (datasource ++ dbRecoveryConf) >>> DatabaseT[Db2].fromDatasourceAndErrorStrategies
+  }
+
+  private val personQueries = PersonQueries.live
+
+  type AppEnv = DatabaseT[Db1] with DatabaseT[Db2] with PersonQueries
+  private val appEnv = database1 ++ database2 ++ personQueries
+
+  override def run: ZIO[ZIOAppArgs with Scope, Any, Any] =
+    for {
+      _ <- Console.printLine("Starting the app")
+      team <- myApp().provideLayer(appEnv)
+      _ <- Console.printLine(team.mkString(", "))
+    } yield ExitCode(0)
+
+  /** Main code for the application. Results in a big ZIO depending on the AppEnv. */
+  def myApp(): ZIO[PersonQueries with DatabaseT[Db2] with DatabaseT[Db1], DbException, List[Person]] = {
+    val queries1: ZIO[PersonQueries with Connection, DbException, List[Person]] = for {
+      _ <- Console.printLine("Creating the table").orDie
+      _ <- PersonQueries.setup
+      _ <- Console.printLine("Inserting the trio").orDie
+      _ <- PersonQueries.insert(Person("Buffy", "Summers"))
+      _ <- PersonQueries.insert(Person("Willow", "Rosenberg"))
+      _ <- PersonQueries.insert(Person("Alexander", "Harris"))
+      _ <- Console.printLine("Reading the trio").orDie
+      trio <- PersonQueries.list
+    } yield trio
+
+    val queries2: ZIO[PersonQueries with Connection, DbException, List[Person]] = for {
+      _ <- Console.printLine("Creating the table").orDie
+      _ <- PersonQueries.setup
+      _ <- Console.printLine("Inserting the mentor").orDie
+      _ <- PersonQueries.insert(Person("Rupert", "Giles"))
+      _ <- Console.printLine("Reading the mentor").orDie
+      mentor <- PersonQueries.list
+    } yield mentor
+
+    val zTrio: ZIO[PersonQueries with DatabaseT[Db1], DbException, List[Person]] = DatabaseT[Db1].transactionOrWiden(queries1)
+    val zMentor: ZIO[PersonQueries with DatabaseT[Db2], DbException, List[Person]] = DatabaseT[Db2].transactionOrWiden(queries2)
+
+    for {
+      trio <- zTrio
+      mentor <- zMentor
+    } yield trio ++ mentor
+  }
+
+}