[ALT] Refactor concourse script to be more modular and fix custom java_home corner case with CLIs

concourse-server/scripts/.env

@@ -92,7 +92,81 @@ cd "$(dirname "$0")"
 APP_HOME="`pwd -P`/.."
 cd $APP_HOME
 
+
+# Parse the java_home value from configuration sources.
+# Checks in priority order (lowest to highest):
+#   1. concourse.prefs (file)
+#   2. concourse.yaml (file)
+#   3. concourse.prefs.dev (file)
+#   4. concourse.yaml.dev (file)
+#   5. CONCOURSE_JAVA_HOME (environment variable) - highest priority
+# Supports both prefs format (key = value) and YAML format (key: value).
+# Matches key names case-insensitively: java_home, javaHome, java-home
+#
+# @return the configured java_home value, or empty string if not configured
+parse_java_home_from_config() {
+    # NOTE: This is a brittle approximation of how the more robust config CLI
+    # parses this value for the concourse script. Here, we cannot use the
+    # config CLI because it sources this file. So, this is a rudimentary
+    # attempt to bootstrap the right java configuration in as similar a way
+    # as possible as concourse does it
+    local config_dir="$APP_HOME/conf"
+    local java_home_value=""
+
+    # Config files in priority order (lowest to highest)
+    local config_files=(
+        "concourse.prefs"
+        "concourse.yaml"
+        "concourse.prefs.dev"
+        "concourse.yaml.dev"
+    )
+
+    # Pattern to match java_home, javaHome, or java-home (case-insensitive)
+    local key_pattern='^(java_home|javaHome|java-home)\s*'
+
+    for file in "${config_files[@]}"; do
+        local filepath="$config_dir/$file"
+        if [ -f "$filepath" ]; then
+            local value=""
+            if [[ "$file" == *.yaml ]]; then
+                # YAML format: key: /path/to/java
+                value=$(grep -iE "${key_pattern}:" "$filepath" 2>/dev/null | head -n1 | sed 's/^[^:]*:[[:space:]]*//' | xargs)
+            else
+                # Prefs format: key = /path/to/java
+                value=$(grep -iE "${key_pattern}=" "$filepath" 2>/dev/null | head -n1 | sed 's/^[^=]*=[[:space:]]*//' | xargs)
+            fi
+            # Only update if we found a non-empty value (higher priority overrides)
+            if [ -n "$value" ]; then
+                java_home_value="$value"
+            fi
+        fi
+    done
+
+    # Environment variable has highest priority (matches config CLI behavior)
+    if [ -n "$CONCOURSE_JAVA_HOME" ]; then
+        java_home_value="$CONCOURSE_JAVA_HOME"
+    fi
+
+    echo "$java_home_value"
+}
+
+
 # Determine the Java command to use to start the JVM.
+# First check for configured java_home, then fall back to detection.
+JAVA_HOME_PREF=$(parse_java_home_from_config)
+
+if [ -n "$JAVA_HOME_PREF" ]; then
+    # Use configured java_home
+    if [ -d "$JAVA_HOME_PREF" ]; then
+        JAVA_HOME="$JAVA_HOME_PREF"; export JAVA_HOME
+    else
+        die "ERROR: java_home is set to an invalid directory: $JAVA_HOME_PREF
+
+Please verify the path exists and contains a valid Java installation."
+    fi
+fi
+
+# Set JAVACMD based on JAVA_HOME (configured or from environment)
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables

concourse-server/scripts/concourse

@@ -289,7 +289,10 @@ CLASSPATH="$APP_HOME/lib/*"
 configure(){
   echo "Loading Concourse Server configuration..."
   CONFIG_SCRIPT=$BIN_DIR"/config"
-  CONFIG=`exec $CONFIG_SCRIPT view -k jmx_port -k remote_debugger_port -k heap_size -k log_level -k force_g1gc -k java_home`
+  CONFIG=$(exec $CONFIG_SCRIPT view -k jmx_port -k remote_debugger_port -k heap_size -k log_level -k force_g1gc -k java_home 2>&1) || {
+    echo "$CONFIG" >&2
+    exit 1
+  }
 
   #jmx_port
   JMX_PREF=`echo "$CONFIG"  | grep -e '^jmx_port\s*=\s*[0-9]\{1,\}$' | head -n1 | cut -d'=' -f2 | tr -d ' '`