build: Symlink to the latest build

With numerous build options, it is not always easy to guess/remember the
output directory for the most recent build. Have the scripts add a
symlink with the name latest-[build type] (latest-kernel,
latest-selftests, latest-perf) pointing to the last successful build in
the $CI_OUTPUT directory.  This makes it very easy to refer to artifacts
from the most recent build.

Author: rnav

build/scripts/build.sh

@@ -164,7 +164,8 @@ if [[ -n $TARGETS ]]; then
     cmd+="-e TARGETS=$TARGETS "
 fi
 
-output_dir=$(get_output_dir "$script_base" "$subarch" "$distro" "$version" "$task" "$DEFCONFIG" "$TARGETS" "$CLANG")
+output_dir=$(get_output_dir "$script_base" "$subarch" "$distro" "$version" "$task" "$DEFCONFIG" "$TARGETS" "$CLANG" "")
+output_symlink=$(get_output_dir "$script_base" "$subarch" "$distro" "$version" "$task" "$DEFCONFIG" "$TARGETS" "$CLANG" "symlink")
 mkdir -p "$output_dir" || exit 1
 
 cmd+="-v $output_dir:/output:rw "
@@ -202,4 +203,10 @@ cmd+="/bin/container-build.sh $task"
 
 (set -x; $cmd)
 
-exit $?
+ret=$?
+if [[ $ret -eq 0  && -n "$output_symlink" ]]; then
+    rm -f $output_symlink
+    ln -s $output_dir $output_symlink
+fi
+
+exit $ret

build/scripts/clean.sh

@@ -11,6 +11,6 @@ script_base="$(realpath "$dir")"
 
 IFS=@ read -r task subarch distro version <<< "$1"
 
-output_dir=$(get_output_dir "$script_base" "$subarch" "$distro" "$version" "$task" "$DEFCONFIG" "$TARGETS" "$CLANG")
+output_dir=$(get_output_dir "$script_base" "$subarch" "$distro" "$version" "$task" "$DEFCONFIG" "$TARGETS" "$CLANG" "")
 
 (set -x ; rm -rf "$output_dir")

build/scripts/lib.sh

@@ -25,6 +25,7 @@ function get_output_dir()
     local defconfig="$6"
     local targets="$7"
     local clang="$8"
+    local symlink="$9"
     local d
 
     if [[ -z "$script_base" || -z "$subarch" || -z "$distro" ]]; then
@@ -41,6 +42,10 @@ function get_output_dir()
     case "$task" in
         kernel) ;&
         clean-kernel)
+	    if [[ -n "$symlink" ]]; then
+		echo "$d/latest-kernel"
+		return 0
+	    fi
             if [[ -n "$defconfig" ]]; then
                 defconfig="${defconfig//\//_}"
                 d="$d/$defconfig"
@@ -49,6 +54,10 @@ function get_output_dir()
         ppctests) ;&
         selftests) ;&
         clean-selftests)
+	    if [[ -n "$symlink" ]]; then
+		echo "$d/latest-selftests"
+		return 0
+	    fi
             if [[ -n "$targets" ]]; then
                 targets=${targets// /_}
                 targets=${targets//\//_}
@@ -59,6 +68,10 @@ function get_output_dir()
             ;;
         perf) ;&
         clean-perf)
+	    if [[ -n "$symlink" ]]; then
+		echo "$d/latest-perf"
+		return 0
+	    fi
             d="$d/perf"
             ;;
     esac