Add Scala buildpack

repo2docker/app.py

@@ -32,6 +32,7 @@
     DockerBuildPack,
     JuliaProjectTomlBuildPack,
     JuliaRequireBuildPack,
+    ScalaBuildPack,
     LegacyBinderDockerBuildPack,
     NixBuildPack,
     PipfileBuildPack,
@@ -94,6 +95,7 @@ def _default_log_level(self):
             DockerBuildPack,
             JuliaProjectTomlBuildPack,
             JuliaRequireBuildPack,
+            ScalaBuildPack,
             NixBuildPack,
             RBuildPack,
             CondaBuildPack,

repo2docker/buildpacks/__init__.py

@@ -4,6 +4,7 @@
 from .conda import CondaBuildPack
 from .julia import JuliaProjectTomlBuildPack
 from .julia import JuliaRequireBuildPack
+from .scala import ScalaBuildPack
 from .docker import DockerBuildPack
 from .legacy import LegacyBinderDockerBuildPack
 from .r import RBuildPack

repo2docker/buildpacks/scala/__init__.py

@@ -0,0 +1 @@
+from .scala_project import ScalaBuildPack

repo2docker/buildpacks/scala/scala_project.py

@@ -0,0 +1,150 @@
+"""Generates a Dockerfile based on an input matrix for Scala"""
+import os
+import toml
+from ..python import PythonBuildPack
+from ..base import BuildPack, BaseImage
+
+class ScalaBuildPack(PythonBuildPack):
+    """
+    Scala build pack which uses conda.
+    """
+
+    # ALL EXISTING SCALA VERSIONS
+    # Note that these must remain ordered, in order for the find_semver_match()
+    # function to behave correctly.
+    all_scalas = [
+        "2.12.12",
+        "2.13.4"
+    ]
+
+    @property
+    def scala_version(self):
+        default_scala_version = self.all_scalas[-1]
+        return default_scala_version
+
+    def get_build_env(self):
+        """Get additional environment settings for Scala and Jupyter
+
+        Returns:
+            an ordered list of environment setting tuples
+
+            The tuples contain a string of the environment variable name and
+            a string of the environment setting:
+            - `SCALA_PATH`: base path where all Scala Binaries and libraries
+                will be installed
+            - `SCALA_DEPOT_PATH`: path where Scala libraries are installed.
+            - `SCALA_VERSION`: default version of scala to be installed
+            - `JUPYTER`: environment variable required by IScala to point to
+                the `jupyter` executable
+
+            For example, a tuple may be `('SCALA_VERSION', '2.13.5')`.
+
+        """
+        return super().get_build_env() + [
+            ("SCALA_PATH", "${APP_BASE}/scala"),
+            ("SCALA_BIN", "${SCALA_PATH}/bin"),
+            ("COURSIER_CACHE", "${SCALA_PATH}/pkg"),
+            ("COURSIER_BIN_DIR", "${SCALA_BIN}"),
+            ("ALMOND_VERSION", "0.11.0"),
+            ("SCALA_VERSION", self.scala_version),
+            #("SCALA_VERSION_MAJOR_TRIMMED", self.scala_version.split),
+            ("SCALA_MAJOR_VERSION_TRIMMED", "2.13"),
+            ("JUPYTER", "${NB_PYTHON_PREFIX}/bin/jupyter"),
+            ("JUPYTER_DATA_DIR", "${NB_PYTHON_PREFIX}/share/jupyter"),
+        ]
+
+    def get_env(self):
+        return super().get_env() + [("SCALA_PROJECT", "${REPO_DIR}")]
+
+    def get_path(self):
+        """Adds path to Scala binaries to user's PATH.
+
+        Returns:
+            an ordered list of path strings. The path to the Scala
+            executable is added to the list.
+
+        """
+        return super().get_path() + ["${SCALA_BIN}"]
+
+    def get_build_scripts(self):
+        """
+        Return series of build-steps common to "ALL" Scala repositories
+
+        All scripts found here should be independent of contents of a
+        particular repository.
+
+        This creates a directory with permissions for installing scala packages
+        (from get_assemble_scripts).
+
+        """
+        return super().get_build_scripts() + [
+            (
+                "root",
+                r"""
+                mkdir -p ${SCALA_BIN} && \
+
+                apt-get -y update && \
+                    apt-get install --no-install-recommends -y \
+                    curl \
+                    openjdk-8-jre-headless \
+                    ca-certificates-java && \
+                    apt-get clean && \
+                    rm -rf /var/lib/apt/lists/*
+                """
+            ),
+            (
+                "root",
+                r"""
+                curl -Lo ${SCALA_BIN}/coursier https://github.com/coursier/coursier/releases/download/v2.0.12/coursier && \
+                chmod +x ${SCALA_BIN}/coursier && \
+                mkdir -p ${COURSIER_CACHE} && \
+                chown ${NB_USER}:${NB_USER} ${COURSIER_CACHE}
+                """
+            ),
+            (
+                "${NB_USER}",
+                r"""
+                coursier launch almond --scala 2.13.4 -- --install --log info --metabrowse --id scala213 --display-name "Scala 2.13" --jupyter-path ${NB_PYTHON_PREFIX}/share/jupyter/kernels/ && \
+                coursier launch almond --scala 2.12.12 -- --install --log info --metabrowse --id scala212 --display-name "Scala 2.12" --jupyter-path ${NB_PYTHON_PREFIX}/share/jupyter/kernels/
+                """,
+            )
+        ]
+
+    def get_assemble_scripts(self):
+        """
+        Return series of build-steps specific to "this" Scala repository
+
+        We make sure that the IScala package gets installed into the default
+        environment, and not the project specific one, by running the
+        IScala install command with SCALA_PROJECT="".
+
+        Instantiate and then precompile all packages in the repos scala
+        environment.
+
+        The parent, CondaBuildPack, will add the build steps for
+        any needed Python packages found in environment.yml.
+        """
+        return super().get_assemble_scripts() + [
+            (
+                "${NB_USER}",
+                r"""
+                echo Implement me
+                """,
+            )
+        ]
+
+    def detect(self):
+        """
+        Check if current repo should be built with the Scala Build pack
+
+        super().detect() is not called in this function - it would return
+        false unless an `environment.yml` is present and we do not want to
+        require the presence of a `environment.yml` to use Scala.
+
+        Instead we just check if the path to `Project.toml` or
+        `ScalaProject.toml` exists.
+
+        """
+        return os.path.exists(self.binder_path("build.sc")) or os.path.exists(
+            self.binder_path("build.sbt")
+        )

tests/scala/scala-2.12.12/build.sbt

@@ -0,0 +1 @@
+scalaVersion := "2.12.12"