Set max.workers for Gradle to fit for the selected workspace class

chunks/lang-java/99-gradle.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+
+# This script calculates the optimal number of Gradle workers for a Gitpod workspace.
+# It uses `gp top` to detect the number of available virtual CPUs, as Gitpod workspaces run in containers
+# and only a subset of the CPU cores known to the Linux kernel are usable.
+
+# Gitpod Cloud:
+# If a workspace is described as "up to X cores", dynamic CPU limiting is active.
+# The script takes the number of cores from the description and divides it by two, since .resources.cpu.limit
+# represents the current limit and depends on CPU utilization.
+
+# Gitpod Enterprise:
+# The script uses the value of .resources.cpu.limit, which represents the static CPU limit.
+
+# In any case, the number of workers is set to (core - 2) to leave some capacity for IDE backend processes.
+
+json=$(gp top --json)
+description=$(echo "$json" | jq -r '.workspace_class.description')
+upto=$(echo "$description" | grep -oP '(?<=Up to )\d+(?= cores)' || echo "")
+limit=$(echo "$json" | jq '.resources.cpu.limit / 1000')
+
+if [[ -z "$upto" ]]; then
+	vcpus=$((limit))
+else
+	vcpus=$((upto / 2))
+fi
+
+# Leave 2 vCPUs for other processes, such as IDE backends
+workers=$((vcpus - 2))
+
+# Ensure at least one worker, even in small workspaces
+workers=$((workers < 1 ? 1 : workers))
+
+# Set an environment variable to configure Gradle
+export GRADLE_OPTS="-Dorg.gradle.workers.max=$workers"
+
+# Output the configuration details
+# printf "upto: $upto\nlimit: $limit\nvcpu: $vcpus\nworkers: $workers\nGRADLE_OPTS=$GRADLE_OPTS\n"

chunks/lang-java/Dockerfile

@@ -25,3 +25,4 @@ RUN curl -fsSL "https://get.sdkman.io" | bash \
              && echo '[[ -s \"/home/gitpod/.sdkman/bin/sdkman-init.sh\" ]] && source \"/home/gitpod/.sdkman/bin/sdkman-init.sh\"' >> /home/gitpod/.bashrc.d/99-java"
 # above, we are adding the sdkman init to .bashrc (executing sdkman-init.sh does that), because one is executed on interactive shells, the other for non-interactive shells (e.g. plugin-host)
 ENV GRADLE_USER_HOME=/workspace/.gradle/
+COPY --chown=gitpod:gitpod 99-gradle.sh /home/gitpod/.bashrc.d/99-gradle.sh