Generate file descriptor set (.desc) with scalapb - scalapb

I am using scalapb in a project that needs to have access to the FileDescriptorSet. Is there a way to have scalapb generate the .desc file in addition to all other class files? Or is there some programatic way of obtaining a FileDescriptorSet from what is already generated?

Yes, to both questions.
If you are using sbt-protoc, you can have the following definition in your SBT file:
PB.protocOptions in Compile := Seq(
"--descriptor_set_out=" +
(baseDirectory in Compile).value.getParentFile / "src" / "main" / "resources" /"out.desc"
)
One caveat is that you would have to create src/main/resources yourself, otherwise you would get an error. It would probably be better to generate into resourceManaged (that would also require creating a directory ahead of time, since protoc doesn't do that)
You can also build a FileDescriptorSet at run time. For each proto file, ScalaPB generates a Scala object with scalaDescriptor (and also javaDescriptor if that's more convenient). The descriptors contains a list of their dependencies which are also FileDesciptors - you can traverse that tree structure and build a list of FileDescriptors which is essentially a FileDescriptorSet.

Related

How can I get the build output directory inside tests run by sbt?

I need to create directories and files for some tests. My project uses sbt as the build tool, and common practice is to use File.createTempFile or similar APIs, but I abhor that practice. I want all files created by my tests to reside somewhere inside the output directory (<module>/target/), so that they'll be removed when I run clean, but otherwise preserved if I have need of them to figure out test failures.
The test framework is not relevant: if your solution requires a particular framework, I'll happily adopt it or figure out how it does the trick and use that.
In short, I need the answer to one of these two questions:
How can I create a file inside the build output directory from a test run by sbt?
How can I find out what is the build output directory for the current project from a test run by sbt?
In ScalaTest, try passing target
settingKey[File]("Main directory for files generated by the build.")
to config map as -Dkey=value. For example, in build.sbt specify
Test / testOptions += Tests.Argument(s"-DtargetDir=${target.value}")
and then define test like so
import org.scalatest._
class ExampleSpec extends fixture.FlatSpec with fixture.ConfigMapFixture with Matchers {
"The config map" should "contain target directory used by sbt" in { configMap =>
configMap should contain key "targetDir"
}

Scala.js compilation destination

I'm working on a Scala.js cross project where the jvm folder represents my server application and jsrepresents my scala.js code.
Whenever i compile my scala.js code via sbt crossJS/fastOptJS the compiled JS ends up in ./js/target/scala-2.11/web-fastopt.js.
I need to have this compiled JS file accessible in the resources of the server project in the jvm folder, so i can server it through my web application. I think i have to do something with artifactPath but i can't seem to get any results from my experiments thus far.
You can simply set the artifactPath of the fastOptJS task (or the fullOptJS task) to the (managed) resources directory of your JVM project:
// In the JS project's settings
artifactPath in fastOptJS in Compile :=
(resourceManaged in jvm in Compile).value /
((moduleName in fastOptJS).value + "-fastopt.js"))
This will put it in the directory, if the you run the fastOptJS task. However, it will not be included in sbt's resources task and it will not automatically be triggered, if you launch your server. Therefore:
// In the JVM project's settings
resources in Compile += (fastOptJS in js).value.data
A couple of notes:
The first step is only necessary, if your web-server does only serve specific directories. Otherwise the second one is enough, as this adds the file to the resources already; where it lies is secondary.
Setting the crossTarget, as in #ochrons' answer will also output all the .class and .sjsir files in the resource directory.
Have a look at Vincent Munier's sbt-play-scalajs for out-of-the-box sbt-web / Scala.js integration (it follows a slightly different approach: It copies the file from the js project, rather than directly placing it in the JVM project. Useful if you have multiple JVM projects).
You can configure the Scala.js SBT plugin to output the JavaScript file in folder of your choosing. For example like this:
// configure a specific directory for scalajs output
val scalajsOutputDir = Def.settingKey[File]("directory for javascript files output by scalajs")
// make all JS builds use the output dir defined later
lazy val js2jvmSettings = Seq(fastOptJS, fullOptJS, packageJSDependencies) map { packageJSKey =>
crossTarget in(js, Compile, packageJSKey) := scalajsOutputDir.value
}
// instantiate the JVM project for SBT with some additional settings
lazy val jvm: Project = sharedProject.jvm.settings(js2jvmSettings: _*).settings(
// scala.js output is directed under "web/js" dir in the jvm project
scalajsOutputDir := (classDirectory in Compile).value / "web" / "js",
This will also store -jsdeps.js and .js.map files in the same folder, in case you want to use those in your web app.
For a more complete example, check out this tutorial which addresses many other issues of creating a more complex Scala.js application.

Include generated resources in a jar (SBT)

I've been writing an SBT plugin that generates resources into resource_managed. I'm now looking to include these generated resources in the generated jar as the SBT docs detail:
Generating resources:
By default, generated resources are not included in the packaged source artifact. To do so, add them as you would other mappings. See Adding files to a package
I've read the docs but honestly how to do this I can't figure out. Can anyone explain it or point me to another project that does this so I can see how they do it?
First just to clarify, they are included in jars containing compiled classes. They are not included in jars containing sources.
By default, generated resources are not included in the packaged
source artifact.
For packageBin the generated files should already be included - just make sure you return all generated files from the generator method. Assuming you want to package them in the sources artifact, this is what you have to do.
Let's assume you have a generator that generates a property file.
lazy val generatePropertiesTask = Def.task {
val file = (Compile / resourceManaged).value / "stack-overflow" / "res.properties"
val contents = s"name=${name.value}\nversion=${version.value}"
IO.write(file, contents)
Seq(file)
}
resourceGenerators in Compile += generatePropertiesTask.taskValue
To include that in the generated sources you have to tell sbt to where the res.properties must be copied in the generated sources artefact. The task, which generates the packaged sources is called packageSrc, therefore you have to set mappings scoped to that task.
mappings in (Compile, packageSrc) += {
((resourceManaged in Compile).value / "stack-overflow" / "res.properties") -> "path/in/jar/res.properties"
}
Because your generator can generate many tasks, and mapping each by hand would be a tedious task, sbt gives you an utility to map multiple paths at once.
mappings in (Compile, packageSrc) ++= {
val allGeneratedFiles = ((resourceManaged in Compile).value ** "*") filter { _.isFile }
allGeneratedFiles.get pair relativeTo((resourceManaged in Compile).value)
}
The first line finds all generated files using path finders and second line maps them to their path in the target jar.

How to create a custom package task to jar a subset of classes in SBT

I am trying to define a separate package task without modifying the original task in compile configuration. This new task will package only a subset of classes conforming an API which we need to be able to share with other teams so they can write plugins for our application. So the end result will be two jars, one with the full application and a second one with a subset of the classes.
I approached this problem by creating a different configuration which I called pluginApi and would redefine the packageBin task within this new configuration so it does not change the original definition of packageBin. This idea was taken from here:
How to create custom "package" task to jar up only specific package in SBT?
In my build.stb I have:
lazy val PluginApi = config("pluginApi") extend(Compile) describedAs("Custom plugin api configuration")
lazy val root = project in file(".") overrideConfigs (PluginApi)
This effectively creates my new configuration and I can call
sbt pluginApi:packageBin
Which generates the complete jar in the same way as compile:packageBin would do. I then try to modify the mappings in the new packageBin task with:
mappings in (PluginApi, packageBin) ~= { (ms: Seq[(File, String)]) =>
ms filter { case (file, toPath) =>
toPath.startsWith("some/path/defining/api")
}
}
but this has no effect. I think the reason is because the call to pluginApi:packageBin is delegated to compile:packageBin rather than it being a cloned task.
I can redefine a new packageBin within the new scope like:
packageBin in PluginApi := {
}
However I would have to rewrite all packageBin functionality instead of reusing existing code. Also, in case that rewriting is unavoidable I am not sure how that implementation would be.
Could somebody provide an example about how to achieve this?
You could have it done as follows
lazy val PluginApi = config("pluginApi").extend(Compile)
inConfig(PluginApi)(Defaults.compileSettings) // you have to have standard
mappings in (PluginApi, packageBin) := {
val original = (mappings in (PluginApi, packageBin)).value
original.filter { case (file, toPath) => toPath.startsWith("some/path/defining/api") }
}
unmanagedSourceDirectories in PluginApi := (unmanagedSourceDirectories in Compile).value
Note that, if you keep your sources in src/main/scala you'll have to override unmanagedSourceDirectories in the newly created configuration.
Normally the unmanagedSourceDirectories contains the configuration name. E.g. src/pluginApi/scala or src/pluginApi/java.
I have had similar problems (with more than one jar per project). Our project uses ant - here you can do it, you just will repeat yourself a lot.
However, I have come to the conclusion that this scenario (2 JARs for one project) actually can be simplified by splitting the project - i.e. making 2 modules out of it.
This way, I don't have to "fight" tools which assume project==artifact (like sbt, maybe maven?, IDEA's default setting,...).
As a bonus point the compiler helps me to verify that my dependencies are correct, i.e. that I did not accidentally make my API package depend on the implementation package - when compiling everything together and only splitting classes apart in the JAR step, you do run the risk of getting an invalid dependency in your setup which you would only see when testing, because during compile time everything is compiled together.

How can I download and add static files to a project using SBT

I want to add some files to test a library that I am writing.
The tests are available in a compressed file in a URI and I just want to download that file and uncompress its contents to a folder before testing.
I was reading the documentation on SBT and there is a Generate sources/resources task.
Also, it seems easy to uncompress a zip file in Scala (see this question).
So I think, I could glue those 2 pieces together, but I wonder if there is some simpler solution.
How about this (syntax for Sbt 0.13.2), in your build.sbt:
resourceGenerators in Test += Def.task {
val location = url("http://path/to/your/zip-file.zip")
IO.unzipURL(location, resourceManaged.value / "my-custom-files").toSeq
}.taskValue