DAML assistant codegen command (digital-asset#2800)

* DAML assistant codegen command, codegen config reader and docs
axman6 · Sep 12, 2019 · 4a9fb1c · 4a9fb1c
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diff --git a/docs/source/index.rst b/docs/source/index.rst
@@ -58,6 +58,7 @@ DAML SDK documentation
    tools/sandbox
    tools/visual
    tools/navigator/index
+   tools/codegen
 
 .. toctree::
    :titlesonly:

diff --git a/docs/source/tools/assistant.rst b/docs/source/tools/assistant.rst
@@ -25,6 +25,7 @@ DAML Assistant (``daml``)
   - Launch the HTTP JSON API: ``daml json-api``
     You can find more information in the
     `README <https://github.com/digital-asset/daml/blob/master/ledger-service/http-json/README.md>`_.
+  - Run :doc:`DAML codegen </tools/codegen>`: ``daml codegen``
 
 - Install new SDK versions manually: ``daml install <version>``
 

diff --git a/docs/source/tools/codegen.rst b/docs/source/tools/codegen.rst
@@ -0,0 +1,98 @@
+.. Copyright (c) 2019 The DAML Authors. All rights reserved.
+.. SPDX-License-Identifier: Apache-2.0
+
+DAML codegen
+############
+
+Introduction
+============
+
+You can use the DAML codegen to generate Java and Scala classes representing DAML contract templates. These classes incorporate all boilerplate code for constructing corresponding ledger :ref:`com.digitalasset.ledger.api.v1.CreateCommand` and :ref:`com.digitalasset.ledger.api.v1.ExerciseCommand`.
+
+Running the DAML codegen
+========================
+
+The basic command to run the DAML codegen is::
+
+  $ daml codegen [java|scala] [options]
+
+There are two modes:
+
+- command line configuration, specifying **all** settings in the command line
+
+- project file configuration, specifying **all** settings in the ``daml.yaml``
+
+Command line configuration
+--------------------------
+
+Help for **DAML to Java** codegen::
+
+  $ daml codegen java --help
+
+Help for **DAML to Scala** codegen::
+
+  $ daml codegen scala --help
+
+Both **DAML to Java** and **DAML to Scala** take the same set of configuration settings::
+
+    Usage: codegen [options] <DAR-file[=package-prefix]>...
+
+    Code generator for the DAML ledger bindings.
+
+      <DAR-file[=package-prefix]>...
+                               DAR file to use as input of the codegen with an optional, but recommend, package prefix for the generated sources.
+      -o, --output-directory <value>
+                               Output directory for the generated sources
+      -d, --decoderClass <value>
+                               Fully Qualified Class Name of the optional Decoder utility
+      -V, --verbosity <value>  Verbosity between 0 (only show errors) and 4 (show all messages) -- defaults to 0
+      -r, --root <value>       Regular expression for fully-qualified names of templates to generate -- defaults to .*
+      --help                   This help text
+
+Project file configuration
+--------------------------
+
+The above settings can be configured in the ``codegen`` element of the DAML project file ``daml.yaml``. Here is an example::
+
+    sdk-version: 0.0.0
+    name: quickstart
+    source: daml
+    scenario: Main:setup
+    parties:
+      - Alice
+      - Bob
+      - USD_Bank
+      - EUR_Bank
+    version: 0.0.1
+    exposed-modules:
+      - Main
+    dependencies:
+      - daml-prim
+      - daml-stdlib
+    codegen:
+      java:
+        package-prefix: com.digitalasset.quickstart.iou
+        output-directory: java-codegen/src/main/java
+        verbosity: 2
+      scala:
+        package-prefix: com.digitalasset.quickstart.iou
+        output-directory: scala-codegen/src/main/scala
+        verbosity: 2
+
+You can run the above configuration to generate **Java** code::
+
+    $ daml codegen java
+
+and to generate **Scala** code::
+
+    $ daml codegen scala
+
+The equivalent **DAML to Java** command line configuration::
+
+    $ daml codegen java ./.daml/dist/quickstart-0.0.1.dar=com.digitalasset.quickstart.iou --output-directory=java-codegen/src/main/java --verbosity=2
+
+and **DAML to Scala** command line configuration::
+
+    $ daml codegen scala ./.daml/dist/quickstart-0.0.1.dar=com.digitalasset.quickstart.iou --output-directory=scala-codegen/src/main/scala --verbosity=2
+
+
diff --git a/language-support/codegen-common/BUILD.bazel b/language-support/codegen-common/BUILD.bazel
@@ -7,24 +7,25 @@ load(
     "da_scala_test",
 )
 
+codegen_common_deps = [
+    "//3rdparty/jvm/ch/qos/logback:logback_classic",
+    "//3rdparty/jvm/com/github/scopt",
+    "//3rdparty/jvm/com/typesafe/scala_logging",
+    "//3rdparty/jvm/io/circe:circe_core",
+    "//daml-assistant/scala-daml-project-config",
+]
+
 da_scala_library(
     name = "codegen-common",
     srcs = glob(["src/main/**/*.scala"]),
     tags = ["maven_coordinates=com.daml:codegen-common:__VERSION__"],
     visibility = ["//visibility:public"],
-    deps = [
-        "//3rdparty/jvm/ch/qos/logback:logback_classic",
-        "//3rdparty/jvm/com/github/scopt",
-    ],
+    deps = codegen_common_deps,
 )
 
 da_scala_test(
     name = "test",
     srcs = glob(["src/test/**/*.scala"]),
     resources = glob(["src/test/resources/**/*"]),
-    deps = [
-        ":codegen-common",
-        "//3rdparty/jvm/com/github/scopt",
-        "//3rdparty/jvm/org/scalatest",
-    ],
+    deps = [":codegen-common"] + codegen_common_deps,
 )
diff --git a/...gen-common/src/main/scala/com/digitalasset/daml/lf/codegen/conf/CodegenConfigReader.scala b/...gen-common/src/main/scala/com/digitalasset/daml/lf/codegen/conf/CodegenConfigReader.scala
@@ -0,0 +1,151 @@
+// Copyright (c) 2019 The DAML Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package com.digitalasset.daml.lf.codegen.conf
+
+import java.io.File
+import java.nio.file.Path
+
+import ch.qos.logback.classic.Level
+import com.digitalasset.assistant.config._
+import io.circe.ACursor
+
+import scala.util.Try
+
+object CodegenConfigReader {
+
+  sealed trait CodegenDest
+  object Java extends CodegenDest
+  object Scala extends CodegenDest
+
+  type Result[A] = Either[ConfigLoadingError, A]
+
+  def readFromEnv(dest: CodegenDest): Result[Conf] =
+    for {
+      sdkConf <- ProjectConfig.loadFromEnv()
+      codegenConf <- codegenConf(sdkConf, dest)
+    } yield codegenConf
+
+  def codegenConf(sdkConf: ProjectConfig, dest: CodegenDest): Result[Conf] =
+    for {
+      dar <- darPath(sdkConf)
+      packagePrefix <- packagePrefix(sdkConf, dest)
+      outputDirectory <- outputDirectory(sdkConf, dest)
+      decoderPkgAndClass <- decoderPkgAndClass(sdkConf, dest)
+      verbosity <- verbosity(sdkConf, dest): Result[Option[Int]]
+      logLevel <- logLevel(verbosity, Level.ERROR)
+      root <- root(sdkConf, dest): Result[Option[List[String]]]
+    } yield
+      Conf(
+        darFiles = Map(dar -> packagePrefix),
+        outputDirectory = outputDirectory,
+        decoderPkgAndClass = decoderPkgAndClass,
+        verbosity = logLevel,
+        roots = root.getOrElse(Nil)
+      )
+
+  private def darPath(sdkConf: ProjectConfig): Result[Path] =
+    for {
+      name <- name(sdkConf)
+      version <- version(sdkConf)
+      dar <- darPath(name, version)
+    } yield dar
+
+  private def name(sdkConf: ProjectConfig): Result[String] =
+    sdkConf.name.flatMap {
+      case Some(a) => Right(a)
+      case None => Left(ConfigMissing("name"))
+    }
+
+  private def version(sdkConf: ProjectConfig): Result[String] =
+    sdkConf.version.flatMap {
+      case Some(a) => Right(a)
+      case None => Left(ConfigMissing("version"))
+    }
+
+  private def darPath(name: String, version: String): Result[Path] =
+    for {
+      darFile <- result(new File(darDirectory, s"$name-$version.dar"))
+      darPath <- result(darFile.toPath)
+    } yield darPath
+
+  private val darDirectory = new File(".daml/dist")
+
+  private def packagePrefix(sdkConf: ProjectConfig, mode: CodegenDest): Result[Option[String]] =
+    codegen(sdkConf, mode)
+      .downField("package-prefix")
+      .as[Option[String]]
+      .left
+      .map(configParseError)
+
+  private def outputDirectory(sdkConf: ProjectConfig, mode: CodegenDest): Result[Path] =
+    codegen(sdkConf, mode)
+      .downField("output-directory")
+      .as[String]
+      .left
+      .map(configParseError)
+      .flatMap(path)
+
+  private def decoderPkgAndClass(
+      sdkConf: ProjectConfig,
+      mode: CodegenDest): Result[Option[(String, String)]] =
+    codegen(sdkConf, mode)
+      .downField("decoderClass")
+      .as[Option[String]]
+      .left
+      .map(configParseError)
+      .flatMap(decoderClass)
+
+  private def decoderClass(fa: Option[String]): Result[Option[(String, String)]] =
+    fa match {
+      case Some(a) => decoderClass(a).map(Some(_))
+      case None => resultR(None)
+    }
+
+  private def decoderClass(s: String): Result[(String, String)] =
+    result(Conf.readClassName.reads(s))
+
+  private def verbosity(sdkConf: ProjectConfig, mode: CodegenDest): Result[Option[Int]] =
+    codegen(sdkConf, mode)
+      .downField("verbosity")
+      .as[Option[Int]]
+      .left
+      .map(configParseError)
+
+  private def logLevel(fa: Option[Int], default: Level): Result[Level] =
+    fa.fold(resultR(default))(readVerbosity)
+
+  private def readVerbosity(a: Int): Result[Level] =
+    result(Conf.readVerbosity.reads(a.toString))
+
+  private def root(sdkConf: ProjectConfig, mode: CodegenDest): Result[Option[List[String]]] =
+    codegen(sdkConf, mode)
+      .downField("root")
+      .as[Option[List[String]]]
+      .left
+      .map(configParseError)
+
+  private def codegen(sdkConf: ProjectConfig, mode: CodegenDest): ACursor =
+    sdkConf.content.hcursor
+      .downField("codegen")
+      .downField(dest(mode))
+
+  private def dest(a: CodegenDest): String = a match {
+    case Java => "java"
+    case Scala => "scala"
+  }
+
+  private def path(a: String): Result[Path] =
+    result(new File(a).toPath)
+
+  private def configParseError(e: Exception): ConfigParseError = ConfigParseError(e.getMessage)
+
+  private def result[A](a: => A): Result[A] =
+    result(Try(a))
+
+  private def result[A](fa: Try[A]): Result[A] =
+    fa.toEither.left.map(e => ConfigLoadError(e.getMessage))
+
+  private def resultR[A](a: A): Result[A] =
+    Right(a): Result[A]
+}
diff --git a/...ge-support/codegen-common/src/main/scala/com/digitalasset/daml/lf/codegen/conf/Conf.scala b/...ge-support/codegen-common/src/main/scala/com/digitalasset/daml/lf/codegen/conf/Conf.scala
@@ -70,13 +70,13 @@ object Conf {
 
   private[conf] val readPath: scopt.Read[Path] = scopt.Read.stringRead.map(s => Paths.get(s))
 
-  private[conf] val readClassName: scopt.Read[(String, String)] = scopt.Read.stringRead.map {
+  val readClassName: scopt.Read[(String, String)] = scopt.Read.stringRead.map {
     case PackageAndClassRegex(p, c) => (p, c)
     case _ =>
       throw new IllegalArgumentException("Expected a Full Qualified Class Name")
   }
 
-  private[conf] val readVerbosity: scopt.Read[Level] = scopt.Read.stringRead.map {
+  val readVerbosity: scopt.Read[Level] = scopt.Read.stringRead.map {
     case "0" => Level.ERROR
     case "1" => Level.WARN
     case "2" => Level.INFO