[DOCKER] UC server container displays welcome message (unitycatalog#392)

This PR changes how the UC server docker image is built (uses the faster
`sbt server/package`) and copies the jars required to start it (to
`jars` directory).

After
unitycatalog@4b7aaa3,
I thought I'd work on changes that would make the behaviour of the UC
server when started consistent regardless whether it's in or outside
Docker container (namely the welcome message at the start and no
warnings).

A Dockerized UC runs in the foreground and containers are removed once
stopped.

Author: jaceklaskowski

Dockerfile

@@ -14,21 +14,18 @@ ARG unitycatalog_user_basedir="${unitycatalog_home}/${unitycatalog_user_home}"
 # and will cause the process to fail when attempting to compile
 # and generate the Uber-Jar. Therefore it is important to choose
 # a size large enough for the compiler to run. 
-ARG sbt_args="-J-Xmx5G"
+ARG sbt_args="-J-Xmx2G"
 # FIXME Pass it from the outside
 ARG unitycatalog_version="0.2.0-SNAPSHOT"
-ARG server_assembly_jar="${unitycatalog_repo}/${unitycatalog_jar}/unitycatalog-server-assembly-${unitycatalog_version}.jar"
+ARG jars_directory="server/target/jars"
 
-# ###### STAGE 1 ###### #
-# Building the Uber-Jar #
-#########################
-
-FROM eclipse-temurin:22-jdk-alpine AS assemble_server
+FROM eclipse-temurin:17-jdk-alpine AS package_server
 
 ARG unitycatalog_repo
 ARG sbt_args
+ARG jars_directory
 
-# Install any required packages
+# Install required packages
 RUN <<EOF
     set -ex;
     apk update;
@@ -37,20 +34,19 @@ RUN <<EOF
     rm -R /var/cache/apk/*;
 EOF
 
-# If the WORKDIR doesn't exist, it will be created
-# https://docs.docker.com/reference/dockerfile/#workdir
 WORKDIR "${unitycatalog_repo}"
 
 COPY . .
 
-# Builds server/target/unitycatalog-server-assembly-0.2.0-SNAPSHOT.jar
-RUN build/sbt ${sbt_args} server/assembly
+# Builds server/target/unitycatalog-server-0.2.0-SNAPSHOT.jar
+RUN build/sbt ${sbt_args} server/package
 
-# ###### STAGE 2 ###### #
-# Running the UC server #
-#########################
+# As a side effect all the required jars to build the UC server
+# are listed in server/target/classpath that is generated at build time
+# Copy the jar files into a single directory
+RUN ./docker/copy_jars_from_classpath.sh ${jars_directory}
 
-FROM eclipse-temurin:22-jre-alpine AS build_uc
+FROM eclipse-temurin:17-jdk-alpine AS build_uc
 
 ARG unitycatalog_uid
 ARG unitycatalog_home
@@ -63,8 +59,8 @@ ARG unitycatalog_user_name
 ARG unitycatalog_user_home
 ARG unitycatalog_user_basedir
 ARG sbt_args
-ARG server_assembly_jar
 ARG unitycatalog_version
+ARG jars_directory
 
 EXPOSE 8081
 
@@ -79,21 +75,18 @@ EOF
 # Define the shell used within the container
 SHELL ["/bin/bash", "-i", "-c", "-o", "pipefail"]
 
-ENV SERVER_ASSEMBLY_JAR="${unitycatalog_jars}/unitycatalog-server-assembly-${unitycatalog_version}.jar"
 ENV UC_SERVER_BIN="${unitycatalog_home}/${unitycatalog_bin}/start-uc-server"
 
-# Create the UC directories
-RUN <<-EOF 
+RUN <<-EOF
     set -ex;
     mkdir -p "${unitycatalog_jars}";
     mkdir -p "${unitycatalog_home}/${unitycatalog_etc}";
     mkdir -p "${unitycatalog_home}/${unitycatalog_bin}";
     mkdir -p "${unitycatalog_home}/${unitycatalog_user_home}";
 EOF
 
-
 # Create system group and user for Unity Catalog
-# ENsure the user created has their HOME pointing to the volume
+# Ensure the user created has their HOME pointing to the volume
 # created to persist user data and the sbt cached files that 
 # are created as a result of compiling the unity catalog.
 # This also ensures that the container can run independently from
@@ -115,11 +108,12 @@ VOLUME  "${unitycatalog_home}"
 
 WORKDIR "$unitycatalog_home"
 
-# Copy the Uber-Jar from the previous stage
-COPY --from=assemble_server "${server_assembly_jar}" "${unitycatalog_jars}/"
+COPY --from=package_server "${server_jar}" "${unitycatalog_jars}/"
 
 # Copy the etc folder which contains the config files and the data folder
-COPY --from=assemble_server "${unitycatalog_repo}/${unitycatalog_etc}" "${unitycatalog_home}/${unitycatalog_etc}/"
+COPY --from=package_server "${unitycatalog_repo}/${unitycatalog_etc}" "${unitycatalog_home}/${unitycatalog_etc}/"
+
+COPY --from=package_server "${unitycatalog_repo}/${jars_directory}" "${unitycatalog_jars}/"
 
 # Create the script that executes the server
 # FIXME It could be already created and simply copied over
@@ -129,27 +123,16 @@ COPY <<-"EOF" "${UC_SERVER_BIN}"
     SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
     ROOT_DIR="$(dirname "$SCRIPT_DIR")"
 
-    if [ -z "$SERVER_ASSEMBLY_JAR" ]; then
-        echo "Server jar '${SERVER_JAR}' not found. Exiting..."
-        exit 1
-    fi
-
-    # Create relative path to jar so that it is able to find the 
-    # configuration files in etc/conf/...
-    relative_path_to_jar="${SERVER_ASSEMBLY_JAR//"$ROOT_DIR/"/}"
-
-    # FIXME Use cp until mainClass in build.sbt is merged to main
-    #   from which this Dockerfile clones the sources from to build the Docker image
-    # SERVER_JAVA_COMMAND="java -jar $relative_path_to_jar $@"
     SERVER_CLASS_NAME="io.unitycatalog.server.UnityCatalogServer"
-    SERVER_JAVA_COMMAND="java -cp $relative_path_to_jar ${SERVER_CLASS_NAME} $@"
+    # A classpath entry consisting simply of * expands to a list of all the jar files in the current directory.
+    # A class path entry that contains * will not match class files.
+    SERVER_JAVA_COMMAND="java -cp "jars/classes:jars/*" ${SERVER_CLASS_NAME} $@"
 
     cd ${ROOT_DIR}
 
     exec ${SERVER_JAVA_COMMAND}
 EOF
 
-
 # Set ownership of directories and Unity Catalog home directory to a less
 # priviledged user
 RUN <<-"EOF"

docker/README.md

@@ -11,6 +11,14 @@ Before you can build the Docker image, install the following tools:
 
 ## Building Unity Catalog Server Image
 
+> [!NOTE]
+>
+> On [Mac computers with Apple silicon](https://support.apple.com/en-us/116943), you may want to change [DOCKER_DEFAULT_PLATFORM](https://docs.docker.com/reference/cli/docker/#environment-variables) environment variable before building the images as follows:
+>
+> ```bash
+> export DOCKER_DEFAULT_PLATFORM=linux/amd64
+> ```
+
 [build-uc-server-docker](./bin/build-uc-server-docker) builds the Docker image of Unity Catalog Localhost Reference Server.
 
 ```bash
@@ -19,7 +27,8 @@ Before you can build the Docker image, install the following tools:
 
 > [!NOTE]
 >
-> `build-uc-server-docker` runs the entire sbt build while creating the Docker image. 
+> `build-uc-server-docker` runs `sbt server/package` build while creating the Docker image.
+> That gives all the required jars files part of the image.
 
 `build-uc-server-docker` creates an image named `unitycatalog` with the version from [version.sbt](../version.sbt).
 
@@ -28,8 +37,8 @@ docker images unitycatalog
 ```
 
 ```text
-REPOSITORY     TAG              IMAGE ID       CREATED              SIZE
-unitycatalog   0.2.0-SNAPSHOT   8b68b233813b   About a minute ago   427MB
+REPOSITORY     TAG              IMAGE ID       CREATED         SIZE
+unitycatalog   0.2.0-SNAPSHOT   5771da356693   7 minutes ago   2.58GB
 ```
 
 ## Running Unity Catalog Server Container
@@ -41,36 +50,31 @@ Once the Docker image of Unity Catalog's Localhost Reference Server is built, yo
 ```
 
 ```text
-Container unitycatalog does not exist. Creating it...
-fbf8a0d2fc6a82f81134c4c50fb4c777399e7095706cb65ff6fe0c158ec43ef4
-The container unitycatalog is running with the following parameters:
-{
-  "Command": "\"/bin/bash bin/start…\"",
-  "CreatedAt": "2024-08-26 18:10:48 +0200 CEST",
-  "ID": "fbf8a0d2fc6a",
-  "Image": "unitycatalog:0.2.0-SNAPSHOT",
-  "Labels": "",
-  "LocalVolumes": "1",
-  "Mounts": "3e4bcb63d68a91…",
-  "Names": "unitycatalog",
-  "Networks": "bridge",
-  "Ports": "0.0.0.0:8081->8081/tcp",
-  "RunningFor": "Less than a second ago",
-  "Size": "32.8kB (virtual 427MB)",
-  "State": "running",
-  "Status": "Up Less than a second"
-}
+❤️ Starting unitycatalog:0.2.0-SNAPSHOT.
+💡 Use Ctrl+C to stop and remove the container.
+###################################################################
+#  _    _       _ _            _____      _        _              #
+# | |  | |     (_) |          / ____|    | |      | |             #
+# | |  | |_ __  _| |_ _   _  | |     __ _| |_ __ _| | ___   __ _  #
+# | |  | | '_ \| | __| | | | | |    / _` | __/ _` | |/ _ \ / _` | #
+# | |__| | | | | | |_| |_| | | |___| (_| | || (_| | | (_) | (_| | #
+#  \____/|_| |_|_|\__|\__, |  \_____\__,_|\__\__,_|_|\___/ \__, | #
+#                      __/ |                                __/ | #
+#                     |___/               v0.2.0-SNAPSHOT  |___/  #
+###################################################################
 ```
 
 `start-uc-server-docker` starts the Unity Catalog server to listen to `8081`.
 
+In another terminal, execute the following command to learn more about the container.
+
 ```bash
 docker container ls --filter name=unitycatalog --no-trunc --format 'table {{.ID}}\t{{.Image}}\t{{.Command}}\t{{.Ports}}'
 ```
 
 ```text
 CONTAINER ID                                                       IMAGE                         COMMAND                           PORTS
-fbf8a0d2fc6a82f81134c4c50fb4c777399e7095706cb65ff6fe0c158ec43ef4   unitycatalog:0.2.0-SNAPSHOT   "/bin/bash bin/start-uc-server"   0.0.0.0:8081->8081/tcp
+1e15b648d6c2669eb83ac12991323ca288e27d9201c4ecbc8dc15ea2bfa6c389   unitycatalog:0.2.0-SNAPSHOT   "/bin/bash bin/start-uc-server"   0.0.0.0:8081->8081/tcp
 ```
 
 Use the regular non-dockerized Unity Catalog CLI to access the server and list the catalogs.
@@ -102,21 +106,11 @@ docker images unitycatalog-cli
 ```
 
 ```text
-REPOSITORY         TAG              IMAGE ID       CREATED              SIZE
-unitycatalog-cli   0.2.0-SNAPSHOT   52502d16934f   About a minute ago   1.48GB
+REPOSITORY         TAG              IMAGE ID       CREATED          SIZE
+unitycatalog-cli   0.2.0-SNAPSHOT   c13a37c4e91e   13 seconds ago   1.62GB
 ```
 
-> [!NOTE]
-> In case you run into the following build exception, restart the CLI docker image build.
-> ```text
-> ❯ ./docker/bin/build-uc-cli-docker
-> ...
-> [error] java.lang.RuntimeException: Failed to find name hashes for io.unitycatalog.cli.utils.CliUtils
-> ...
-> [error] (cli / Compile / compileIncremental) Failed to find name hashes for io.unitycatalog.cli.utils.CliUtils
-> ```
-
-## Access Unity Catalog Localhost Reference Server
+## Access Unity Catalog Server
 
 [start-uc-cli-docker](./bin/start-uc-cli-docker) uses the `unitycatalog-cli` image to run Unity Catalog CLI in a Docker container.
 

docker/bin/build-uc-cli-docker

@@ -12,7 +12,7 @@ echo "Changing directory to $project_dir"
 cd "$project_dir" || exit
 
 if [[ -r "$docker_file" ]]; then
-    echo "Building $image_tag from Dockerfile $docker_file"
+    echo "Building $image_tag using the build definition from $docker_file"
     docker buildx build \
       --progress=plain \
       --no-cache \

docker/bin/build-uc-server-docker

@@ -5,14 +5,14 @@ script_dir=$(dirname "$0")
 project_dir=$(dirname "$(dirname "$(realpath "$script_dir")")")
 docker_file="Dockerfile"
 container_name="unitycatalog"
-container_version=$(< "$project_dir/version.sbt" cut -d '"' -f2)
+container_version=$(cut -d '"' -f2 "$project_dir/version.sbt")
 image_tag=$container_name:$container_version
 
 echo "Changing directory to $project_dir"
 cd "$project_dir" || exit
 
 if [[ -r "$docker_file" ]]; then
-    echo "Building $image_tag from Dockerfile $docker_file"
+    echo "Building $image_tag using the build definition from $docker_file"
     docker buildx build \
       --progress=plain \
       --no-cache \

docker/bin/start-uc-server-docker

@@ -3,27 +3,13 @@
 script_dir=$(dirname "$0")
 project_dir=$(dirname "$(dirname "$(realpath "$script_dir")")")
 container_name="unitycatalog"
-container_version=$(< "$project_dir/version.sbt" cut -d '"' -f2)
-
-container_details=$(docker container ls -a -q --filter "name=$container_name")
-container_running=$(docker ps -q --filter "name=$container_name")
-
-if [ -z "$container_details" ]; then
-    echo "Container $container_name does not exist. Creating it..."
-    docker run \
-       --tty \
-       --publish 8081:8081 \
-       --detach \
-       --name "$container_name" \
-       "$container_name:$container_version"
-else
-    if [ -n "$container_running" ]; then
-        echo "Container $container_name already running, skipping."
-    else
-        echo "Container $container_name already exists, starting it."
-        docker start $container_name
-    fi
-fi
-
-echo "The container $container_name is running with the following parameters:"
-docker ps --format '{{json .}}' | jq -r --arg CONTAINER_NAME "$container_name" 'select(.Names == $CONTAINER_NAME)'
+container_version=$(cut -d '"' -f2 "$project_dir/version.sbt")
+
+echo "❤️ Starting $container_name:$container_version."
+echo "💡 Use Ctrl+C to stop and remove the container."
+docker run \
+   --rm \
+   --tty \
+   --publish 8081:8081 \
+   --name "$container_name" \
+   "$container_name:$container_version"

docker/copy_jars_from_classpath.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+JARS_DIR="server/target/jars"
+if [ "$1" != "" ]; then
+  JARS_DIR="$1"
+fi
+
+echo "Creating $JARS_DIR directory"
+mkdir -p "$JARS_DIR"
+
+ONE_SINGLE_CLASSPATH_LINE=$(< server/target/classpath)
+
+IFS=':' read -ra JARS <<< "$ONE_SINGLE_CLASSPATH_LINE"
+for jar_file in "${JARS[@]}"
+do
+  # -R recursively copies two classes directories into one classes output directory
+  # happily, -R works with files too
+  cp -R "$jar_file" "$JARS_DIR"
+done

uc-cli.dockerfile

@@ -23,7 +23,7 @@ ARG cli_assembly_jar="${unitycatalog_repo}/${unitycatalog_jar}/unitycatalog-cli-
 # Building the Uber-Jar #
 #########################
 
-FROM eclipse-temurin:22-jdk-alpine AS assemble_cli
+FROM eclipse-temurin:17-jdk-alpine AS assemble_cli
 
 ARG unitycatalog_repo
 ARG sbt_args
@@ -50,7 +50,7 @@ RUN build/sbt ${sbt_args} cli/assembly
 # Running the UC server #
 #########################
 
-FROM eclipse-temurin:22-jre-alpine AS build_cli
+FROM eclipse-temurin:17-jdk-alpine AS build_cli
 
 ARG unitycatalog_uid
 ARG unitycatalog_home