Add BuildInfo so the Akka gRPC version becomes available for specifying dependencies

[ennru]

eg for

    libraryDependencies += "com.lightbend.play" %% "play-grpc-runtime" % "$project.version$",
    libraryDependencies += "com.lightbend.play" %% "lagom-javadsl-grpc-testkit" % "$project.version$" % Test

[raboof]

👍

In akka-grpc this BuildInfo lives in the codegen subproject, so that it's available for all plugins (not just sbt)

For the runtime library in sbt, we could even pull it in automatically via the code generator (we do the same in akka-grpc)

[ennru]

Added #306, not sure if you had something smarter in mind.

[ignasi35]

After reviewing the code in #306 I think we're taking the wrong approach.

I think Play and Lagom users should extract the version of Akka and Akka-HTTP from their main framework (lagom/play) and not play-grpc. This leaves only the versions of akka-grpc and grpc itself which may already be extractred from Akka-gRPC's BuildInfo.

So, instead of adding BuildInfo in play-grpc (like we did in #306) I would add akkaHttpVersion on Play's PlayVersion.

Usage would look like this: (taken from https://github.com/playframework/play-samples/tree/2.8.x/play-scala-grpc-example)

// plugins.sbt
enablePlugins(BuildInfoPlugin)
val playGrpcV = "0.9.1
buildInfoKeys := Seq[BuildInfoKey]("playGrpcVersion" -> playGrpcV)
buildInfoPackage := "play.scala.grpc.sample"

// build.sbt
val CompileDeps = Seq(
  guice,
  // play-grpc from this build (see plugins.sbt)
  "com.lightbend.play"      %% "play-grpc-runtime"   % BuildInfo.playGrpcVersion, 
  "com.typesafe.akka"       %% "akka-discovery"      % PlayVersion.akkaVersion,
  "com.typesafe.akka"       %% "akka-http"           % PlayVersion.akkaHttpVersion,
  // Test Database
  "com.h2database" % "h2" % "1.4.199"
)

val TestDeps = Seq(
  "com.lightbend.play"      %% "play-grpc-scalatest" % BuildInfo.playGrpcVersion % Test, 
  "com.lightbend.play"      %% "play-grpc-specs2"    % BuildInfo.playGrpcVersion % Test, 
  "com.typesafe.play"       %% "play-test"           % PlayVersion.current     % Test,
  "com.typesafe.play"       %% "play-specs2"         % PlayVersion.current     % Test,
  "org.scalatestplus.play"  %% "scalatestplus-play"  % "5.0.0" % Test, 
)

[ignasi35]

Raised playframework/playframework#10519

[ennru]

@ignasi35 The important bit was to communicate the Akka gRPC version. You are right that the other versions should come from more relevant sources.

[raboof]

I think Play and Lagom users should extract the version of Akka and Akka-HTTP from their main framework (lagom/play) and not play-grpc

Why? Since we're currently actively working on akka-grpc, I think there is a good likelyhood that akka-grpc will use newer akka-http features, and thus require a newer akka-http version than play/lagom currently requires. Since Akka HTTP generally maintains binary compatibility that should work fine, right? (unless exceptional cases where play used internal API's or we dropped the ball in Akka HTTP)

[ignasi35]

Why? Since we're currently actively working on akka-grpc, I think there is a good likelyhood that akka-grpc will use newer akka-http features, and thus require a newer akka-http version than play/lagom currently requires. Since Akka HTTP generally maintains binary compatibility that should work fine, right? (unless exceptional cases where play used internal API's or we dropped the ball in Akka HTTP)

Correct. An I'm not against akka-grpc having a BuildInfo that includes the Akka-HTTP versions used to compile that akka-grpc version. My point is that a play/lagom user opting into using play-grpc should not get yet another set of versions to choose from (the proposed PlayGrpcBuildInfo discussed here).

I agree that akka-grpc is more actively maintained and I like the idea of allowing the user to choose between AkkaGrpcBuildInfo.akkaHttpVersion and PlayVersion.akkaHttpVersion as long as they are aware of the risks.

My comment was only about PlayGrpcBuildInfo introducing what looks like an alias of AkkaGrpcBuildInfo.

[raboof]

I like the idea of allowing the user to choose between AkkaGrpcBuildInfo.akkaHttpVersion and PlayVersion.akkaHttpVersion as long as they are aware of the risks.

Aah, yeah. That makes sense to me, PlayGrpcBuildInfo.akkaHttpVersion would be redundant 👍

[ignasi35]

(this is a slightly different discussion)

I was even thinking the play-grpc build could reuse the versions from akka-grpc or play using something lilke:

    val akka     = AkkaGrpcBuildInfo.akkaVersion
    val akkaHttp = AkkaGrpcBuildInfo.akkaHttpVersion

or

    val akka     = PlayVersion.akkaVersion
    val akkaHttp = PlayVersion.akkaHttpVersion

in

play-grpc/project/Dependencies.scala

Lines 13 to 14 in b40b32c

	val akka = "2.6.5"
	val akkaHttp = "10.1.12"

So we lock versions a bit more. I'm not sure it is a good idea, though.