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add serviceName field to ConsulDiscoverable typeclass #322

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Merged
bpholt merged 1 commit into from
Dec 18, 2025
Merged

add serviceName field to ConsulDiscoverable typeclass #322

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3 changes: 3 additions & 0 deletions ...s/src/test/scala-2/com/dwolla/consul/smithy4s/ConsulDiscoverableSpecPerScalaVersion.scala
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
package some_other_package

import com.dwolla.consul.ServiceName
import com.dwolla.consul.smithy4s._
import com.dwolla.test.HelloService
import munit.FunSuite
Expand All @@ -10,11 +11,13 @@ trait ConsulDiscoverableSpecPerScalaVersion { self: FunSuite =>
val serviceUri: Uri = UriFromService(HelloService)
private val serviceHost: Host = HostFromService(HelloService)
private val serviceUriAuthority: Uri.Authority = UriAuthorityFromService(HelloService)
private val serviceName: ServiceName = ServiceNameFromService(HelloService)

test("ConsulDiscoverable typeclass macro constructs a working instance of the typeclass") {
assertEquals(ConsulDiscoverable[HelloService].host, serviceHost)
assertEquals(ConsulDiscoverable[HelloService].uriAuthority, serviceUriAuthority)
assertEquals(ConsulDiscoverable[HelloService].uri, serviceUri)
assertEquals(ConsulDiscoverable[HelloService].serviceName, serviceName)
}

test("ConsulDiscoverable typeclass macro returns no instance when the type parameter isn't a Smithy Service") {
Expand Down
19 changes: 13 additions & 6 deletions smithy4s-tests/src/test/scala-2/com/dwolla/consul/smithy4s/UriFromServiceSpec.scala
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@@ -1,25 +1,32 @@
package com.dwolla.consul.smithy4s

import com.comcast.ip4s._
import cats.syntax.all._
import com.dwolla.consul.ServiceName
import com.dwolla.consul.smithy.Discoverable
import com.dwolla.test.HelloService
import munit.FunSuite
import org.http4s.Uri
import org.http4s.syntax.all._

class UriFromServiceSpec extends FunSuite {
test("Service URI is derived from Smithy hint at compile time") {
import org.http4s.syntax.all._

val uri = UriFromService(com.dwolla.test.HelloService)
assertEquals(uri, uri"consul://hello-world")
assertEquals(uri.some, HelloService.hints.get[Discoverable].map(d => Uri(scheme = scheme"consul".some, authority = Uri.Authority(host = Uri.RegName(d.serviceName.value)).some)))
}

test("Service Host is derived from Smithy hint at compile time") {
val uri = HostFromService(com.dwolla.test.HelloService)
assertEquals(uri, Uri.Host.fromIp4sHost(host"hello-world"))
assertEquals(uri.some, HelloService.hints.get[Discoverable].map(d => Uri.RegName(d.serviceName.value)))
}

test("Service URI.Authority is derived from Smithy hint at compile time") {
val uri = UriAuthorityFromService(com.dwolla.test.HelloService)
assertEquals(uri, Uri.Authority(host = Uri.Host.fromIp4sHost(host"hello-world")))
assertEquals(uri.some, HelloService.hints.get[Discoverable].map(d => Uri.Authority(host = Uri.RegName(d.serviceName.value))))
}

test("ServiceName is derived from Smithy hint at compile time") {
val serviceName = ServiceNameFromService(com.dwolla.test.HelloService)
assertEquals(serviceName.some, HelloService.hints.get[Discoverable].map(d => ServiceName(d.serviceName.value)))
}

test("unannotated Smithy services are rejected at compile time") {
Expand Down
35 changes: 16 additions & 19 deletions smithy4s/src/main/scala-2/com/dwolla/consul/smithy4s/ConsulDiscoverablePlatform.scala
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@@ -1,8 +1,10 @@
package com.dwolla.consul.smithy4s

import cats.syntax.all._
import com.dwolla.consul.smithy._
import org.http4s.Uri.{Host, Scheme}
import com.dwolla.consul.ServiceName
import com.dwolla.consul.smithy
import com.dwolla.consul.smithy.{ServiceName => _, _}
import org.http4s.Uri
import org.typelevel.scalaccompat.annotation.nowarn212
import smithy4s.Hints

Expand All @@ -15,18 +17,16 @@ trait ConsulDiscoverablePlatform {
}

object ConsulDiscoverableMacros {
@nowarn212("msg=local val (liftableScheme|liftableHost) in method makeInstance is never used")
@nowarn212("msg=local val (liftableServiceName|liftableHost) in method makeInstance is never used")
def makeInstance[Alg[_[_]]](c: whitebox.Context): c.Expr[ConsulDiscoverable[Alg]] = {
import c.universe.{Try => _, _}

implicit val liftableScheme: Liftable[Scheme] = Liftable { scheme: Scheme =>
q"""_root_.org.http4s.Uri.Scheme.unsafeFromString(${scheme.value})"""
}
implicit val liftableHost: Liftable[Host] = Liftable { host: Host =>
implicit val liftableHost: Liftable[Uri.Host] = Liftable { host: Uri.Host =>
q"""_root_.org.http4s.Uri.Host.unsafeFromString(${host.value})"""
}

val consulScheme = DiscoveryMacros.consulScheme.some
implicit val liftableServiceName: Liftable[ServiceName] = Liftable { serviceName: ServiceName =>
q"""_root_.com.dwolla.consul.ServiceName(${serviceName.value})"""
}

def findHintsInTree(tpe: Tree): Either[String, Hints] =
Try {
Expand All @@ -45,28 +45,25 @@ object ConsulDiscoverableMacros {
_.get(Discoverable.tagInstance)
.toRight(s"could not find Discoverable hint for $tpe")

val getHostFromDiscoverable: PartialFunction[Discoverable, Either[String, Host]] = {
case Discoverable(ServiceName(serviceName)) =>
Host.fromString(serviceName)
val getHostFromDiscoverable: PartialFunction[Discoverable, Either[String, (ServiceName, Uri.Host)]] = {
case Discoverable(smithy.ServiceName(serviceName)) =>
Uri.Host.fromString(serviceName)
.leftMap(_.message)
.tupleLeft(ServiceName(serviceName))
}

def hostToConsulDiscoverableExpr(tpe: Tree): Host => c.Expr[ConsulDiscoverable[Alg]] = host =>
def hostToConsulDiscoverableExpr(tpe: Tree): (ServiceName, Uri.Host) => c.Expr[ConsulDiscoverable[Alg]] = (serviceName, host) =>
c.Expr[ConsulDiscoverable[Alg]](
q"""
new _root_.com.dwolla.consul.smithy4s.ConsulDiscoverable[$tpe] {
override def host: _root_.org.http4s.Uri.Host = $host
override def uriAuthority: _root_.org.http4s.Uri.Authority = _root_.org.http4s.Uri.Authority(host = host)
override def uri: _root_.org.http4s.Uri = _root_.org.http4s.Uri(scheme = $consulScheme, authority = _root_.scala.Option(uriAuthority))
}
_root_.com.dwolla.consul.smithy4s.ConsulDiscoverable.make[$tpe]($serviceName, $host)
""")

c.macroApplication match {
case TypeApply(_, List(tpe)) if tpe.symbol.companion != NoSymbol =>
val maybeExpr = findHintsInTree(tpe)
.flatMap(getDiscoverableFromHints(tpe))
.flatMap(getHostFromDiscoverable)
.map(hostToConsulDiscoverableExpr(tpe))
.map(hostToConsulDiscoverableExpr(tpe).tupled)

maybeExpr.fold(c.abort(c.enclosingPosition, _), identity)
case TypeApply(_, List(tpe)) if tpe.symbol.companion == NoSymbol =>
Expand Down
35 changes: 33 additions & 2 deletions smithy4s/src/main/scala-2/com/dwolla/consul/smithy4s/UriFromService.scala
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Original file line number Diff line number Diff line change
@@ -1,11 +1,14 @@
package com.dwolla.consul.smithy4s

import com.dwolla.consul.smithy.{Discoverable, ServiceName}
import com.dwolla.consul.smithy.Discoverable
import com.dwolla.consul.smithy
import org.http4s.Uri
import smithy4s.{Hints, Service}
import cats.syntax.all._
import com.dwolla.consul.ServiceName
import org.http4s.Uri.{Host, Scheme}
import org.http4s.syntax.all._
import org.typelevel.scalaccompat.annotation.nowarn212

import scala.reflect.macros.blackbox

Expand Down Expand Up @@ -36,7 +39,7 @@ object DiscoveryMacros {
.get(Discoverable.tagInstance)
.toRight(s"could not find Discoverable hint for ${cleanService.symbol.fullName}")
.flatMap {
case Discoverable(ServiceName(serviceName)) =>
case Discoverable(smithy.ServiceName(serviceName)) =>
Host.fromString(serviceName)
.leftMap(_.message)
}
Expand All @@ -45,6 +48,29 @@ object DiscoveryMacros {
}
.fold(c.abort(c.enclosingPosition, _), identity)
}

@nowarn212("msg=local val liftableServiceName in method makeServiceName is never used")
def makeServiceName[Alg[_[_, _, _, _, _]]](c: blackbox.Context)
(service: c.Expr[smithy4s.Service[Alg]]): c.Expr[ServiceName] = {
import c.universe.{Try => _, _}

implicit val liftableServiceName: Liftable[ServiceName] = Liftable { serviceName: ServiceName =>
q"""_root_.com.dwolla.consul.ServiceName(${serviceName.value})"""
}

val cleanService = c.untypecheck(service.tree.duplicate)

c.eval(c.Expr[Hints](q"$cleanService.hints"))
.get(Discoverable.tagInstance)
.toRight(s"could not find Discoverable hint for ${cleanService.symbol.fullName}")
.map {
case Discoverable(serviceName) => ServiceName(serviceName.value)
}
.map { serviceName =>
c.Expr[ServiceName](q"$serviceName")
}
.fold(c.abort(c.enclosingPosition, _), identity)
}
}

object UriAuthorityFromService {
Expand All @@ -61,3 +87,8 @@ object UriFromService {
def apply[Alg[_[_, _, _, _, _]]](service: Service[Alg]): Uri =
macro DiscoveryMacros.makeUri[Alg]
}

object ServiceNameFromService {
def apply[Alg[_[_, _, _, _, _]]](service: Service[Alg]): ServiceName =
macro DiscoveryMacros.makeServiceName[Alg]
}
16 changes: 13 additions & 3 deletions smithy4s/src/main/scala/com/dwolla/consul/smithy4s/ConsulDiscoverable.scala
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Original file line number Diff line number Diff line change
@@ -1,17 +1,27 @@
package com.dwolla.consul.smithy4s

import cats.syntax.all._
import com.dwolla.consul.ServiceName
import org.http4s.Uri
import org.http4s.Uri.Host
import org.http4s.syntax.all._

import scala.annotation.implicitNotFound

@implicitNotFound("Instances are only available for Smithy4s Services annotated with @discoverable")
trait ConsulDiscoverable[Alg[_[_]]] {
def host: Host
sealed trait ConsulDiscoverable[Alg[_[_]]] {
def host: Uri.Host
def uriAuthority: Uri.Authority
def uri: Uri
def serviceName: ServiceName = ServiceName(host.value) // default implementation for MiMa compatibility, but it's never used in practice
}

object ConsulDiscoverable extends ConsulDiscoverablePlatform {
def apply[Alg[_[_]] : ConsulDiscoverable]: ConsulDiscoverable[Alg] = implicitly

def make[Alg[_[_]]](name: ServiceName, dest: Uri.Host): ConsulDiscoverable[Alg] = new ConsulDiscoverable[Alg] {
override def host: Uri.Host = dest
override def uriAuthority: Uri.Authority = Uri.Authority(host = host)
override def uri: Uri = Uri(scheme = scheme"consul".some, authority = uriAuthority.some)
override def serviceName: ServiceName = name
}
}