new: [compose-core] add ``memory.limit`` metadata value to limit container's memory

bin/compose-core

@@ -108,6 +108,50 @@ quick_cat_stdin() { local IFS=''; while read -r line; do echo "$line"; done ; }
 export -f quick_cat_file quick_cat_stdin md5_compat
 
 
+read-0-err() {
+    local ret="$1" eof="" idx=0 last=
+    read -r -- "${ret?}" <<<"0"
+    shift
+    while [ "$1" ]; do
+        last=$idx
+        read -r -d '' -- "$1" || {
+            ## Put this last value in ${!ret}
+            eof="$1"
+            read -r -- "$ret" <<<"${!eof}"
+            break
+        }
+        ((idx++))
+        shift
+    done
+    [ -z "$eof" ] || {
+        if [ "$last" != 0 ]; then
+            echo "Error: read-0-err couldn't fill all value" >&2
+            read -r -- "$ret" <<<"127"
+        else
+            if [ -z "${!ret}" ]; then
+                echo "Error: last value is not a number, did you finish with an errorlevel ?" >&2
+                read -r -- "$ret" <<<"126"
+            fi
+        fi
+        false
+    }
+}
+
+
+wyq() {
+    local exp="$1"
+    yq e -e -0 "$1"
+    printf "%s" "$?"
+}
+
+
+wyq-r() {
+    local exp="$1"
+    yq e -e -0 -r=false "$1"
+    printf "%s" "$?"
+}
+
+
 clean_cache() {
     local i=0
     for f in $(ls -t "$CACHEDIR/"*.cache.* 2>/dev/null | tail -n +500); do
@@ -3187,7 +3231,8 @@ _get_docker_compose_mixin_from_metadata_cached() {
     local service="$1" charm="$2" metadata="$3" \
           has_build_dir="$4" \
           cache_file="$CACHEDIR/$FUNCNAME.cache.$(echo "$*" | md5_compat)" \
-          metadata_file metadata volumes docker_compose subordinate image mixin mixins
+          metadata_file metadata volumes docker_compose subordinate image \
+          mixin mixins tmemory memory limit docker_memory
 
     if [ -e "$cache_file" ]; then
         #debug "$FUNCNAME: STATIC cache hit $1"
@@ -3260,6 +3305,54 @@ _get_docker_compose_mixin_from_metadata_cached() {
         fi
         mixins+=("build: $(charm.get_dir "$charm")/build")
     fi
+    limit=$(e "$metadata" | yq '.limit' 2>/dev/null) || return 1
+    [ "$limit" == "null" ] && limit=""
+    if [ -n "$limit" ]; then
+        if ! read-0-err E tmemory memory < <(e "$limit" | wyq ".memory | type, .memory") ||
+           [ "$E" != 0 ]; then
+            err "Unexpected error in ${DARKPINK}$charm${NORMAL}'s metadata when parsing ${WHITE}.limit${NORMAL}"
+            return 1
+        fi
+        case "$tmemory" in
+            '!!str'|'!!int')
+                docker_memory="$(e "$memory" | numfmt --from iec)" || {
+                    err "Invalid format specified for .limit.memory: '$memory'."
+                    return 1
+                }
+                ;;
+            '!!float')
+                err "Unexpected value in ${DARKPINK}$charm${NORMAL}'s metadata for ${WHITE}.limit.memory${NORMAL}."
+                echo "  You need to specify a unit (like 'K', 'M', 'G' ...)." >&2
+                return 1
+                ;;
+            '!!null')
+                :
+                ;;
+            *)
+                err "Unexpected type '${tmemory#!!}' in ${DARKPINK}$charm${NORMAL}'s metadata" \
+                    "for ${WHITE}.limit.memory${NORMAL}."
+                echo "  You need to check ${DARKPINK}$charm${NORMAL}'s metadata " \
+                     "for ${WHITE}.limit.memory${NORMAL} and provide a valid value" >&2
+                echo "  Example values: '1.5G', '252M', ..." >&2
+                return 1
+                ;;
+        esac
+        if [ -n "$docker_memory" ]; then
+            if [[ "$docker_memory" -lt 6291456 ]]; then
+                err "Can't limit service to lower than 6M."
+                echo "  Specified limit of $memory (=$docker_memory) is lower than docker's min limit of 6M (=6291456)." >&2
+                echo "  The provided limit to memory is lower than minimum memory for a container." >&2
+                echo "  Please remove memory limit in ${DARKPINK}$charm${NORMAL}'s metadata or raise it." >&2
+                return 1
+            fi
+            mixins+=(
+                "mem_limit: $docker_memory"
+                "memswap_limit: $docker_memory"
+            )
+        fi
+    fi
+    ## Final merging
+
     mixin=$(merge_yaml_str "${mixins[@]}") || {
         err "Failed to merge mixins from ${DARKPINK}${charm}${NORMAL} metadata."
         return 1